ARTICLE ABSTRACT. PEDIATRICS Volume 118, Number 5, November peds doi: /peds.

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1 ARTICLE Comprison of the Immunogenicity nd Rectogenicity of Prophylctic Qudrivlent Humn Ppillomvirus (Types 6, 11, 16, nd 18) L1 Virus-Like Prticle Vccine in Mle nd Femle Adolescents nd Young Adult Women Stn L. Block, MD, Terry Noln, PhD, MBBS b, Crlos Sttler, MD c, Eliv Brr, MD c, Ktherine E. D. Gicoletti, MStt c, Colin D. Mrchnt, MD d, Xvier Cstellsgué, MD, PhD, MPH e, Steven A. Rusche, MS c, Suznne Lukc, BS c, Jnine T. Bryn, PhD c, Pul F. Cvnugh, Jr, PhD c, Keith S. Reisinger, MD, MPH f, for the Protocol 016 Study Group Kentucky Peditric Reserch, Inc, Brdstown, Kentucky; b Murdoch Children s Reserch Institute nd School of Popultion Helth, University of Melbourne, Melbourne, Austrli; c Merck Reserch Lbortories, Wyne, West Point, nd Blue Bell, Pennsylvni, nd Rhwy, New Jersey; d Deprtment of Peditrics, Boston University School of Medicine, Boston, Msschusetts; e Institut Ctlà d Oncologi, Servei d Epidemiologi i Registre del Càncer, L Hospitlet de Llobregt, Brcelon, Spin; f Primry Physicins Reserch, Pittsburgh, Pennsylvni Finncil Disclosure: Dr Block hs received reserch support from nd served s consultnt for Merck & Co, Inc. Dr Noln hs received trvel funding for scientific presenttion from Merck & Co, Inc. Dr Mrchnt hs received reserch support from Merck & Co, Inc. Dr Cstellsgué hs served s consultnt for Snofi Psteur MSD. Dr Reisinger receives reserch support from nd serves s scientific dvisory bord member nd speker for Merck & Co, Inc. Drs Sttler, Brr, Gicoletti, Bryn, nd Cvnugh nd Mr Rusche nd Ms Lukc re employees of Merck & Co, Inc, nd own stock nd/or hold stock options in the compny. ABSTRACT OBJECTIVE. Prophylctic vccintion of 16- to 23-yer-old femles with qudrivlent humn ppillomvirus (types 6, 11, 16, 18) L1 virus-like prticle vccine hs been shown to prevent type-specific humn ppillomvirus infection nd ssocited clinicl disese. We conducted noninferiority immunogenicity study to bridge the efficcy findings in young women to predolescent nd dolescent girls nd boys, who represent primry trget for humn ppillomvirus vccintion. METHODS. We enrolled 506 girls nd 510 boys (10 15 yers of ge) nd 513 femles (16 23 yers of ge). Prticipnts were vccinted on dy 1, t month 2, nd t month 6, nd serology testing ws performed on dy 1 nd t months 3 nd 7 on blinded smples. Neutrlizing ntibody concentrtions were determined using type-specific immunossys nd summrized s geometric men titers nd seroconversion rtes. Vccine tolerbility lso ws ssessed. RESULTS. By month 7, seroconversion rtes were 99% for ll 4 humn ppillomvirus types in ech group. By month 7, compred with women, nti humn ppillom virus geometric men titers in girls or boys were noninferior nd were 1.7- to 2.7-fold higher. Most ( 97%) injection-site dverse events were mild to moderte in intensity. Significntly more boys (13.8%) nd girls (12.8%) thn women (7.3%) reported fevers 37.8 C within 5 dys of vccintion. Most (96.4%) fevers were mild ( 39 C). CONCLUSIONS. Noninferior immunogenic responses to ll 4 humn ppillomvirus types in the qudrivlent vccine permit the bridging of efficcy dt tht were generted in young women to girls. The results in boys lend support for the implementtion of gender-neutrl humn ppillomvirus vccintion progrms. This vccine generlly ws well tolerted. peds doi: /peds Key Words HPV, vccine, immunogenicity, rectogenicity, peditric, noninferiority Abbrevitions HPV humn ppillomvirus VLP virus-like prticle PCR polymerse chin rection clia competitive Luminex xmap-bsed immunossy mmu millimerck unit VRC vccintion report crd AE dverse event GMT geometric men titer PPI per-protocol immunogenicity CI confidence intervl SIL squmous intrepithelil lesion Accepted for publiction Jul 28, 2006 Address correspondence to Stn L. Block, MD, Kentucky Peditric Reserch, Inc, 201 S 5th St, Brdstown, KY E-mil: slblock@pol.net PEDIATRICS (ISSN Numbers: Print, ; Online, ). Copyright 2006 by the Americn Acdemy of Peditrics PEDIATRICS Volume 118, Number 5, November

2 ANOGENITAL HUMAN PAPILLOMAVIRUS (HPV) infection is the most common virl infection of the nogenitl trct worldwide, with cumultive lifetime risk for infection pproching 70%. 1 HPV infection in the nogenitl trct is often clered spontneously without clinicl sequele; however, if not clered, infection cn led to clinicl disese tht rnges from erly mild dysplsi or genitl wrts to severe dysplsi nd cervicl cncer. 2,3 Worldwide, cses of cervicl nd other genitl cncers re cused by HPV infection nnully with deths ttributble to cervicl cncer. 4 The lifetime risk for cquired genitl wrts exceeds 10%. 5 The HPV fmily includes 100 types, 35 to 40 of which infect the epithelium of the nogenitl trct. All genitl HPV types cn cuse dysplsi nd visible lesions. However, only subgroup of HPV types cuse dysplsi tht cn led to cncer. HPVs 16 nd 18 cuse 70% of cervicl nd other HPV-relted genitl cncers. They lso re the custive gents for 25% to 35% nd 50% to 70%, respectively, of low-grde nd high-grde cervicl dysplstic lesions. 1 HPVs 6 nd 11 cuse 90% of ll cses of clssic condylom cumint (genitl wrts) s well s 10% to 15% of low-grde cervicl dysplstic lesions, both of which rrely cuse cncer, 6 nd 90% of juvenile onset recurrent respirtory ppillomtosis. 7 Recombinnt synthesis of the HPV L1 protein, the mjor constituent of the virl cpsid, results in ssembly of virus-like prticles (VLPs), which, when dministered with djuvnt, re potent immunogens, inducing immune responses tht re higher thn tht seen fter nturl infection. 8 In recent plcebo-controlled study of to 23-yer-old femles, prophylctic (ie, before infection) 3-dose regimen of qudrivlent HPV (types 6, 11, 16, nd 18) VLP L1 vccine resulted in robust nti HPV specific neutrlizing ntibody responses tht led to 90% reduction in the combined incidence of HPV type specific persistent infection or cervicl or externl genitl disese. 9 In subsequent study of this vccine in women ged 16 to 26 yers, similr robust immune responses were observed, leding to 100% prevention of HPV 16 nd HPV 18 relted cervicl intrepithelil neoplsi grdes 2/3 nd denocrcinom in situ nd pre- or noninvsive cervicl cncer, compred with plcebo. 10 These findings suggested tht vccintion of individuls who re not yet infected with HPV will reduce substntilly their risk for developing cervicl cncer nd genitl wrts lter in life. The highest risk for cquiring HPV infection is within the first 5 yers fter sexul debut. Therefore, n HPV vccine idelly should be dministered to children who re ged 15 or younger, t time before the high-risk period fter sexul debut Studies to demonstrte the efficcy of prophylctic HPV vccines in predolescents nd dolescents re not fesible given legl nd ethicl issues regrding evlutions of sexul ctivity in this popultion nd the reltively low rte of exposure t this ge. Therefore, efficcy studies of these vccines hve not been conducted in dolescents who re younger thn 16 yers. To bridge the demonstrted vccine efficcy findings in 16- to 23-yer-old femles to predolescents nd dolescents, who represent primry trget for HPV vccintion, we conducted n immunogenicity substudy within lrger dose-response study (for gthering vccine product expirtion dting informtion). The objective of this immunogenicity substudy ws to determine whether HPV L1 VLP vccine-induced nti-hpv neutrlizing ntibody responses in 10- to 15-yer-old girls nd boys re comprble to responses in 16- to 23-yer-old femles. 9,15 METHODS Prticipnts Sixty-one clinicl centers (cdemic medicl centers nd privte prctice bsed reserch centers) in Asi, Austrli, Europe, Ltin Americ, nd North Americ prticipted in this clinicl study between December 7, 2002, nd September 20, The institutionl review bord or locl ethics committee of ech study center pproved this protocol. Prents of ll study prticipnts who were younger thn 18 yers provided written informed consent, nd, when required, these study prticipnts lso provided written informed ssent. All dult study prticipnts provided written informed consent before their prticiption in the study. The study ws designed to enroll 3 popultions: 10- to 15-yer-old girls, 10- to 15-yer-old boys, nd 16- to 23-yer-old femles. For the 2 younger popultions, prticipnts were required to be sexully nïve t enrollment nd throughout the study nd to be generlly helthy. For the older popultion, prticipnts were required to be generlly helthy nd hve n intct uterus, no evidence of gross purulent cervicitis, no history of genitl wrts, no previous bnorml Ppnicolou tests, no history of cervicl intrepithelil neoplsi, nd lifetime history of no more thn 4 sexul prtners. Individuls were excluded from prticiption when they were pregnnt (determined by urine or serum -humn chorionic gondotropin testing), were llergic to ny vccine component, hd received ny blood product or component in the previous 6 months, hd ny known immune or cogultion disorder, or hd received ny inctivted vccine product within 14 dys before enrollment or ny live vccine product within 21 dys before enrollment. Vccine Preprtion nd Administrtion A description of the qudrivlent HPV (types 6, 11, 16, nd 18) L1 VLP vccine ws reported previously. 9 Briefly, the vccine consists of mixture of 4 recombinnt HPV type specific VLPs (Merck Reserch Lborto BLOCK et l

3 ries, West Point, PA) tht consist of the L1 mjor cpsid proteins of HPVs 6, 11, 16, nd 18, ech of which were synthesized in Scchromyces cerevisie The 4 VLP types were dsorbed onto morphous luminum hydroxyphosphte sulfte djuvnt fter purifiction. In ddition to contining 225 g of luminum djuvnt, ech 0.5-mL dose of the vccine test product contined the following mounts of L1 VLP: 20 g of HPV 6, 40 g of HPV 11, 40 g of HPV 16, nd 20 g of HPV 18. The pproprite concentrtions of HPV type specific L1 VLP ntigens were determined from the results of previous study. 9 The vccine ws dministered by intrmusculr injection (0.5 ml) into the upper rm or thigh. Study Design The tril (sponsor protocol no. V ) ws n gend gender-strtified noninferiority immunogenicity study with trget enrollment of 500 prticipnts in ech study cohort. It ws designed to compre the immune response to ech HPV type fter 3-injection regimen of full dose of qudrivlent HPV L1 VLP vccine through month 7. The 10- to 15-yer-old prticipnts lso were followed for 1 yer fter the initil vccintion visit to collect dditionl sfety-relted dt. This study ws substudy within rndomized, doubleblinded, multi-dose study tht ws designed to obtin dt tht were needed to determine specifictions for vccine product expirtion dting. It exmined the immunogenic response of lower vccine doses (20%, 40%, nd 60%) in girls nd women compred with the full dose (100%) reported here (Merck & Co, Inc, dt on file). Rndomiztion ws with respect to the multidose study. With respect to the noninferiority comprison of immunogenic responses between dults nd dolescents reported here, the study ws not blinded or rndomized; however, ll biologicl smples were coded to mintin nlyst blinding. All prticipnts in this noninferiority immunogenicity study received the full dose of vccine. Prticipnts received full dose of vccine on dy 1, t month 2 ( 3 weeks), nd t month 6 ( 3 weeks). All prticipnts were required to be febrile (orl temperture 37.8 C) within 24 hours before ech injection. All femle prticipnts underwent pregnncy testing tht ws bsed on urine or serum nlyses for -humn chorionic gondotropin before ech vccintion. Prticipnts who were found to be pregnnt were not vccinted. The older femle group ws instructed to use effective contrception through month 7 of the study nd refrin from sexul ctivity or use of vginl medictions or clensing products within 48 hours of ny scheduled clinic visit tht included pelvic exmintion. Only femle prticipnts in the older ge group underwent Ppnicolou testing. Prticipnts with bnorml Ppnicolou tests t dy 1 were followed up s per the locl stndrd of cre. Externl genitl nd cervicl swbs were obtined for polymerse chin rection (PCR) detection of HPVs 6, 11, 16, or 18 DNA, indictive of infection, in the 16- to 23-yer-old prticipnts on dy 1 nd t month 7. HPVs 6, 11, 16, nd 18 DNA were detected using fluorescence-bsed multiplex PCR ssys tht were designed to detect DNA from the L1, E6, nd E7 genes of ech virus. Immunogenicity Serum smples were obtined t dy 1, t month 3, nd t month 7 in ll prticipnts. Smples were stored t 20 C or below until testing. Anti-HPV levels were determined using n HPV type specific competitive Luminex xmap-bsed immunossy (clia), s previously described. 18,19 This ssy mesures only neutrlizing nti- HPV ntibodies, rther thn the brod ssortment of vccine-induced nti-hpv ntibodies (some of which re not neutrlizing). Antibody levels were expressed s millimerck units (mmu) per milliliter. The scles for ech type-specific ssy were set using stndrds from vccinted primtes. Ech scle ws set seprtely; therefore, cross-ssy comprisons of nti-hpv levels re not vlid. The lower limits of detection for the nti-hpv 6, 11, 16, nd 18 clias were 4.1 mmu6/ml, 3.0 mmu11/ ml, 10.2 mmu16/ml, nd 2.9 mmu18/ml, respectively. Assy precision ws estimted to be 21.7%, 20.4%, 23.0%, nd 15.9% for the nti-hpv 6, 11, 16, nd 18 clias respectively. Prticipnts were considered nti-hpv 6, 11, 16, or 18 seropositive when their nti-hpv ntibody titers were 20 mmu6/ml, 16 mmu11/ml, 20 mmu16/ml, or 24 mmu18/ml, respectively. Rectogenicity nd Overll Vccine Sfety All prticipnts were observed for t lest 30 minutes fter ech vccintion for ny immedite rection, with prticulr ttention to ny evidence of hypersensitivity rection. Adult prticipnts recorded their orl tempertures 4 hours fter ech vccine injection nd dily for the next 4 dys on vccintion report crd (VRC). The VRCs for 10- to 15-yer-olds were completed by prent or legl gurdin. Any systemic or locl dverse events (AEs) tht occurred within 14 dys of vccine injection were recorded on ech prticipnt s VRC. Prticipntreported AEs lso were collected t months 2, 3, nd 7 using n interview process. Investigtors were instructed to ssign cuslity to AEs on the bsis of exposure, time course, likely cuse, nd consistency with the test vccine s known profile. Vccine-relted AEs were those tht were determined by the investigtor to be possibly, probbly, or definitely vccine relted. For ech AE, prticipnts were sked to rte the symptom s mild (wreness of sign or symptom but esily tolerted), moderte (discomfort enough to cuse interference with usul ctivities), or severe (incpcitting with inbility to work or do usul ctivity). Serious AEs were predefined s ny AEs tht resulted in deth, were deemed PEDIATRICS Volume 118, Number 5, November

4 by the investigtor to be life-thretening, or resulted in persistent or significnt disbility or incpcity. An independent sfety monitor ws put in plce to monitor prticipnt sfety continuously becuse this ws the first study of this qudrivlent vccine in 10- to 15-yer-olds. Sttisticl Anlysis Immunogenicity The primry hypothesis of this study ws tht the immune responses to the qudrivlent HPV (types 6, 11 16, nd 18) L1 VLP vccine in 10- to 15-yer-old boys or girls re noninferior to the immune responses tht re observed in 16- to 23-yer-old femles. The end points of the study were the geometric men titers (GMTs) of neutrlizing ntibodies for ech HPV type t week 4 postdose 3 (month 7) nd the percentges of prticipnts who seroconverted to ech HPV type by month 7. To demonstrte noninferiority of the qudrivlent HPV L1 VLP vccine s immunogenicity in either boys or girls compred with young dult women, noninferiority hd to be met for both primry end points nd for ech of the 4 HPV vccine types. The smple size for the study ws chosen to provide 99% power to declre noninferiority in immunogenic responses nd seroconversion rtes for t lest 1 of the popultions (girls or boys compred with women). A step-up multiplicity procedure ws used to control the overll type I error rte.025 (1 sided) with respect to the 2 demogrphic group comprisons. The primry nlysis pproch ws per-protocol. To be included in the per-protocol immunogenicity (PPI) popultion for ech HPV type, prticipnts were required to hve received 3 pproprite doses of vccine within prespecified visit intervls, to hve hd the month 7 serum smple drwn within prespecified intervl reltive to dose 3, not to hve violted the protocol in wys tht potentilly would interfere with the vccine s immunogenicity, nd to be seronegtive to the respective HPV type t dy 1. Becuse the L1 proteins for HPV 6 nd HPV 11 re 92% homologous t the mino cid level, ll prticipnts were required to be both nti HPV 6 nd nti HPV 11 seronegtive to be included in either of the HPV 6 nd HPV 11 PPI popultions. Note tht becuse there were differing numbers of prticipnts who were seropositive to the different HPV types t dy 1, the numbers of prticipnts in the per-protocol study popultions re type specific. Only 16- to 23-yer-olds were required to undergo genitl smpling for PCR detection of HPV. They were required to be PCR negtive to the respective vccine types throughout the course of the study. Confirmtory nlyses of ntibody responses in prticipnts who were nïve to ll HPV types nd hd immunogenicity dt lso were conducted. This popultion included prticipnts who were not included in the per-protocol nlysis (eg, becuse of protocol violtions). Confirmtory nlyses of ntibody responses in prticipnts who were nïve to the respective HPV types nd hd immunogenicity dt lso were conducted. This popultion included prticipnts, regrdless of generl protocol violtions, who received 3 pproprite doses of vccine nd remined PCR negtive to the respective vccine types throughout the course of the study. To ddress the primry hypothesis of noninferiority, the immune responses of girls nd boys were compred seprtely with those of women. Noninferiority with respect to nti-hpv GMTs ws ddressed by 4 1-sided tests of noninferiority (1 for ech HPV vccine type) conducted t the level (multiplicity djusted). Ech test ws ddressed by nlysis of vrince, modeling the postdose 3 nturl log of the nti-hpv clia vlue s function of geogrphic region, demogrphic group (girls, boys, or women), nd interction of demogrphic group by geogrphic region (ll modeled s fixed effects). The fold difference in GMTs (girls/women, boys/ women) ws computed s the nti-log of the estimted group difference in the nlysis of vrince model long with its ssocited 95% confidence intervl (CI). For noninferiority of GMTs to be declred in girls or boys versus women, the lower bound of the multiplicitydjusted 95% CIs for the GMT rtios (girls/women, boys/women) hd to be 0.5 for ll HPV types. This lower confidence bound ws chosen to be consistent with other trils in the qudrivlent HPV vccine progrm nd bsed on regultory guidnce nd clinicl judgment regrding cliniclly meningful differences in immune responses. To test for noninferiority of seroconversion rtes in boys or girls to those in women, we conducted 4 1-sided tests of noninferiority (1 corresponding to ech HPV type) t the level (multiplicity djusted). These tests were conducted using the method of Miettinen nd Nurminen, 20 which llows strtifiction by region. When the lower bounds of the multiplicity-djusted 95% CIs for the differences in seroconversion rtes (% boys or girls % women) were 5 percentge points or more for ll HPV types, noninferiority ws concluded. Sfety All prticipnts who received t lest 1 injection nd hd follow-up dt were included in the sfety nlysis. AEs were summrized descriptively s frequencies nd percentges by prticipnt group nd type of AE, by vccintion visit, nd cross ll vccintion visits. In ddition, risk differences nd ssocited 95% CIs were computed compring girls nd boys seprtely with women cross ll vccintion visits with respect to AEs with n incidence 1% in either group being compred. Elevted tempertures ( 37.8 C, orl equivlent) within 5 dys fter ech vccintion were summrized in similr 2138 BLOCK et l

5 mnner. P vlues were computed for group differences in elevted tempertures nd rectogenicity (injectionsite pin, swelling, nd redness). Pirwise comprisons of prespecified AEs nd elevted tempertures between boys nd women nd between girls nd women were mde using the method of Miettinen nd Nurminen 20 t 2-sided.05 significnce level. No djustments for multiple comprisons were mde for sfety nlyses. RESULTS Demogrphics A totl of 1529 prticipnts were enrolled in this bridging substudy (Fig 1), nd 1525 prticipnts received t lest 1 injection of the vccine. Of those prticipnts, 1450 (94.8%) completed the vccintion regimen. Loss to follow-up (2.4%) nd withdrwl of consent (1.9%) were the 2 most frequent resons for discontinution (Fig 1). Both dolescent groups generlly were well blnced with regrd to bseline demogrphic chrcteristics (ge, weight, nd rce/ethnicity) except for geogrphic region (Tble 1). As expected, the popultion of 16- to 23-yerolds on verge ws hevier nd hd somewht lrger BMIs thn the younger ge groups. Among the 16- to 23-yer-old femles, 88% were nonvirgins with men (SD) ge of first sexul intercourse of 17 (2) yers. The medin number of lifetime mle or femle sexul prtners in this older ge group ws 2, nd 19.5% of prticipnts reported previous pregnncy. Of 16- to 23-yerolds who hd Ppnicolou test result from dy 1 (n 509), 41 (8.1%) hd dignosis suggestive of squmous intrepithelil lesion (SIL), which included 19 (3.8%) typicl squmous cells of undetermined significnce; 3 (0.6%) typicl squmous cells of undetermined significnce, cnnot rule out high-grde SIL; nd 19 (3.8%) low-grde SIL. All 3 groups were well blnced with respect to rce nd ethnicity. At enrollment, serum ntibody concentrtions for HPV 6, 11, 16, or 18 tht were greter thn the predefined seropositive threshold vlues for 1 or more HPV type, indictive of previous exposure to the respective FIGURE 1 Prticipnt disposition flowchrt. Nine girls nd 3 boys were lost to follow-up fter month 7. Two boys nd 8 women discontinued the vccintions but completed the study. PEDIATRICS Volume 118, Number 5, November

6 TABLE 1 Bseline Demogrphics of Enrolled Study Prticipnts Girls (10 15 y old; N 506) Boys (10 15 y old; N 510) Women (16 23 y old; N 513) Age, men (SD), y 12.6 (1.6) 12.6 (1.6) 20.0 (2.1) Weight, men (SD), kg 50.8 (15.3) 53.1 (17.1) 60.6 (12.9) BMI, men (SD), kg/m (4.8) 20.8 (4.5) 23.0 (4.6) Rce/ethnicity, n (%) Asin 59 (11.7) 86 (16.9) 59 (11.5) Blck 30 (5.9) 23 (4.5) 33 (6.4) Hispnic Americn 85 (16.8) 49 (9.6) 58 (11.3) Ntive Americn 0 (0) 5 (1.0) 0 (0) White 321 (63.4) 341 (66.9) 354 (69.0) Other 11 (2.2) 6 (1.2) 9 (1.8) Geogrphic region, n (%) United Sttes nd Cnd 168 (33.2) 222 (43.5) 163 (31.8) Ltin Americ 154 (30.4) 80 (15.7) 85 (16.6) Asi-Pcific 95 (18.8) 147 (28.8) 112 (21.8) Europe 89 (17.6) 61 (12.0) 153 (29.8) vccine HPV types, were detected in 3.8% (19 of 506), 1.4% (7 of 508), nd 13.7% (70 of 511) of girls, boys, nd women, respectively. Prticipnts in the 16- to 23- yer-old ge group underwent HPV DNA testing t dy 1. Among these prticipnts, 9.6% were positive for t lest 1 vccine HPV type, indicting the possibility of ongoing HPV infection. Overll, 19.4% (97 of 501) of prticipnts in the 16- to 23-yer-old ge group were positive for HPV 6, 11, 16, or 18 by serology or PCR detection of HPV DNA t dy 1. Dy 1 nti-hpv GMTs in 16- to 23-yer-olds who were serology positive on dy 1 nd PCR negtive through month 7 were 54.8 mmu/ ml, 52.5 mmu/ml, 61.2 mmu/ml, nd 51.5 mmu/ml for HPVs 6, 11, 16, nd 18, respectively. Anti-HPV Neutrlizing Antibody Responses Tble 2 displys the results of the sttisticl nlyses of noninferiority of month 7 nti-hpv GMTs compring 10- to 15-yer-old girls nd boys seprtely with 16- to 23-yer-old femles for ech vccine HPV type in the PPI popultion. Tble 2 displys the estimted GMTs (djusted for region) for ech group, long with the estimted fold difference in GMTs (younger group divided by older group) nd the corresponding 95% CIs. Becuse the lower bound of the 95% CI for the fold difference in GMTs exceeded 0.5 for ll HPV types, the sttisticl criterion for noninferiority for this end point ws met, supporting the conclusion tht nti-hpv GMTs in both 10- to 15-yer-old girls nd boys re noninferior to those in 16- to 23-yer-old femles. The observed postdose 3 nti-hpv GMTs in girls nd boys were observtionlly higher thn those tht were observed in women for ll 4 types. The 16- to 23-yer-old femles hd consistently lower GMTs thn the 10- to 15-yer-olds t ech time point for ll geogrphic regions. The GMT fold difference between 10- to 15-yer-olds nd 16- to 23-yer-old femles in Europe ws the smllest. More thn 99% of prticipnts seroconverted by month 7 to ll 4 HPV types (Tble 3), meeting the criterion for noninferior immune responses between popultions for this primry end point s well. Robust nti-hpv GMTs were observed by 1 month postdose 2 in ll 3 groups. The GMTs t 1 month postdose 2 (month 3) for ntibodies to HPVs 6, 11, 16, nd 18 in girls (636 mmu/ml, 776 mmu/ml, 2834 mmu/ml, nd 369 mmu/ml) nd boys (678 mmu/ml, 796 mmu/ ml, 3026 mmu/ml, nd 414 mmu/ml) were observtionlly higher thn those tht were observed in 16- to 23-yer-old femles (438 mmu/ml, 550 mmu/ml, 1698 mmu/ml, nd 215 mmu/ml). This is consistent with the higher immunogenicity response tht ws observed in girls nd boys thn in women t month 7. Seroconversion rtes to the 4 HPV types by 1 month TABLE 2 Noninferiority of GMTs in Girls nd Boys Versus Women t Month 7 in the PPI Popultion Assy (clia) Girls Boys Women GMT Rtio (95% CI) n GMT (mmu/ml) n GMT (mmu/ml) n GMT (mmu/ml) Girls/Women Boys/Women Anti HPV b ( ) 1.81 b ( ) Anti HPV b ( ) 1.87 b ( ) Anti HPV b ( ) 2.21 b ( ) Anti HPV b ( ) 2.68 b ( ) Bsed on sttisticl model djusting for region. b Noninferiority P BLOCK et l

7 TABLE 3 Noninferiority of Seroconversion Response t Month 7 in the PPI Popultion Assy (clia) Girls Boys Women Difference b Girls-Women (95% CI) n Seropositive, % n Seropositive, % n Seropositive, % Difference b Boys-Women (95% CI) Anti HPV ( 0.9 to 1.3) c 0.0 ( 1.0 to 1.3) c Anti HPV ( 0.9 to 1.3) c 0.0 ( 1.0 to 1.3) c Anti HPV ( 0.9 to 1.3) c 0.0 ( 1.0 to 1.4) c Anti HPV ( 0.2 to 2.5) c 0.6 ( 0.6 to 2.4) c Bsed on sttisticl model djusting for region. Seropositivity determined reltive to thresholds of 20, 16, 20, nd 24 mmu/ml for HPV 6, 11, 16, nd 18, respectively. b Percentge point difference. c Noninferiority P.001. postdose 2 exceeded 97.5% in ll groups for ll HPV types. Anlyses of type-specific immune responses in ll type-specific HPV-nïve (ie, seronegtive t dy 1 nd PCR-negtive from dy 1 through month 7) prticipnts with serology dt vilble from the study supported the conclusions of the per-protocol nlyses. A posthoc pooled nlysis tht included prticipnts from ll groups who were HPV seropositive on dy 1 reveled month 3 nti-hpv GMTs of 1071 mmu/ml, 4435 mmu/ ml, 3955 mmu/ml, nd 892 mmu/ml nd month 7 nti-hpv GMTs of 1138 mmu/ml, 3909 mmu/ml, 5256 mmu/ml, nd 1613 mmu/ml for HPVs 6, 11, 16, nd 18, respectively. These GMTs were numericlly higher thn those in the PPI popultion, suggesting type-specific nmnestic response in prticipnts who hd previous seroconversion s result of infection, similr to previous findings with monovlent HPV 16 L1 VLP vccine. 8 Sfety nd Rectogenicity The 3-dose regimen of the vccine generlly ws well tolerted in ech prticipnt group (Tble 4). Discontinutions s result of AEs were rre (3 totl), nd the incidence of serious AEs tht occurred within 14 dys of ny injection ws low. The most commonly reported systemic AEs were hedches (23.2%) nd fever (13.1%). The proportions of prticipnts with ny vccine-relted injection site or systemic AE cross the 3 groups were slightly higher fter vccintion visit 1 thn fter vccintion visit 2 or 3. The proportions of prticipnts who reported t lest 1 injection-site or systemic AE were lower mong girls nd boys thn mong 16- to 23-yer-old femles. The distributions of intensity rtings nd sizes of specific injection-site AEs fter ech vccintion visit were comprble to those tht were observed overll (ie, fter ny vccintion visit). There ws 1 deth in the study. A 15-yer-old boy died suddenly 27 dys fter receiving his second dose of the vccine. The likely cuse of deth ws ftl ventriculr rrhythmi. His utopsy ws negtive for ny clinicl findings. The investigtor deemed the deth unrelted to the study vccine becuse of the lck of ny plusible or temporl reltionship. Three prticipnts experienced nonftl serious AEs from which they ll recovered. A 15-yer-old girl experienced n intentionl overdose of chlorphenirmine tblets nd rsenicum homeopthic tblets 13 dys fter receiving dose 2 tht ws judged by the reporting physicin to not be vccine relted. A 15-yer-old boy experienced lower bdominl pin ccompnied by vomiting nd dirrhe 9 dys fter receiving dose 1 tht ws not vccine relted, s determined by the reporting physicin. The third serious AE ws vginl hemorrhge, which occurred 26 dys postdose 2 in 13-yer-old girl nd ws judged by the reporting physicin probbly to be vccine relted. After second episode of vginl bleed- TABLE 4 Clinicl AEs Reported During Dys 1 to 15 Postdose 1, 2, nd 3 nd Across All Vccintion Visits in All Prticipnts Who Received t Lest 1 Injection of Vccine Postdose 1 Postdose 2 Postdose 3 Across All Vccintions Girls Boys Women Girls Boys Women Girls Boys Women Girls Boys Women n % n % n % n % n % n % n % n % n % n % n % n % Prticipnts with follow-up Prticipnts with Vccine-relted AEs Vccine-relted injection-site AEs Vccine-relted systemic AEs Serious AEs b Percentges clculted bsed on the number of prticipnts with follow-up. b There ws 1 deth nd 1 nonftl serious AE outside the 15-dy postvccintion period, which re described in more detil in the text. PEDIATRICS Volume 118, Number 5, November

8 ing experienced by this prticipnt 42 dys fter receiving dose 3 of the vccine, the prticipnt improved nd bleeding stopped 1 dy fter initition of 7-dy course of tretment with estrdiol vlerte tblets, medroxyprogesterone cette tblets, nd ferric hydroxide polymltose complex tblets. Then 125 dys postdose 3, vginl bleeding ws experienced gin for 9 dys. On consulttion with 2 gynecologists, this AE ws considered to be ttributble to previous condition nd the lst bleeding episode ttributble to withdrwl of the hormonl medictions listed. The mjority of injection-site AEs were mild to moderte in intensity (Tble 5). Across the 3 groups, the proportion of prticipnts who reported injection-site pin ws highest fter the first dose, nd the proportion of prticipnts who reported swelling nd redness ws higher fter the second nd third doses. A sttisticlly significnt higher proportion of the 16- to 23-yer-olds reported injection-site erythem or pin compred with the other 2 groups (Tble 5). A significntly higher proportion of 10- to 15-yer-old girls nd boys experienced fever ( 37.8 C) within 5 dys of ny injection compred with the older popultion (12.8%, 13.8%, nd 7.3% respectively; Tble 6). Most (96.4%) of the fevers experienced were 39 C. However, 5 prticipnts (1 girl, 3 boys, nd 1 womn) experienced mximum orl temperture of between 39.9 C nd 40.9 C, nd 1 girl experienced fever of 40.9 C (postdose 1). A higher percentge (25.4%) of 16- to 23-yer-old prticipnts reported tking medictions such s ntirheumtic nd nti-inflmmtory drugs (eg, nonsteroidl nti-inflmmtory drugs) within 15 dys of ech injection com- TABLE 5 Summry of Injection-Site AEs Reported During Dys 1 to 5 Postdose 1, 2, nd 3 nd Across All Vccintions, in All Prticipnts Who Received t Lest 1 Injection of Vccine Injection Site AE Girls (10 15 y old), n (%) Boys (10 15 y old), n (%) Women (16 23 y old), n (%) Pin/tenderness/soreness No. of prticipnts who reported Postdose (59.9) 265 (53.0) 321 (64.6) Postdose (55.4) 211 (42.6) 296 (61.4) Postdose (58.8) 185 (38.1) 295 (63.6) Across ll vccintions 398 (79.4) 357 (71.4) 429 (86.3) P.004 b.001 b Totl no. of times this AE ws reported Intensity of AEs c Mild 712 (79.5) 576 (84.0) 736 (77.2) Moderte 166 (18.5) 104 (15.2) 206 (21.6) Severe 17 (1.9) 6 (0.9) 10 (1.0) Redness (erythem) No. of prticipnts who reported Postdose 1 34 (6.8) 31 (6.2) 48 (9.7) Postdose 2 52 (10.4) 35 (7.1) 50 (10.4) Postdose 3 63 (12.9) 50 (10.3) 69 (14.9) Across ll vccintions 101 (20.2) 93 (18.6) 130 (26.2) P.025 b.004 b Totl No. of times this AE ws reported Intensity of AEs c Mild 133 (89.3) 101 (85.6) 143 (84.1) Moderte 14 (9.4) 11 (9.3) 16 (9.4) Severe 2 (1.3) 4 (3.4) 5 (2.9) Injection-site swelling No. of prticipnts who reported Postdose 1 39 (7.8) 27 (5.4) 48 (9.7) Postdose 2 69 (13.9) 50 (10.1) 63 (13.1) Postdose 3 73 (14.9) 59 (12.1) 66 (14.2) Across ll vccintions 127 (25.3) 107 (21.4) 125 (25.2) P.943 b.161 b Totl No. of times this AE ws reported Intensity of AEs c Mild 136 (72.3) 103 (74.6) 151 (79.5) Moderte 43 (22.9) 23 (16.7) 24 (12.6) Severe 9 (4.8) 11 (8.0) 9 (4.7) Percentges were clculted on the bsis of the number of prticipnts with follow-up (see Tble 4 for denomintors). b P vlue for comprison with the proportion of 16- to 23-yer-old femles with the specific injection-site AE, undjusted for multiple comprisons. c Percentges were clculted s 100 (No. of AEs of specific intensity/totl AEs reported). Not ll column percentges dd up to 100% becuse the intensity rtings for some AEs were unknown BLOCK et l

9 TABLE 6 Mximum Reported Tempertures During Dys 1 to 5 Postdose 1, 2, nd 3 nd Across All Vccintions in All Prticipnts Who Received t Lest 1 Injection of Vccine nd Provided Sfety Follow-up Dt Postdose 1 Postdose 2 Postdose 3 Across All Vccintions Girls Boys Women Girls Boys Women Girls Boys Women Girls Boys Women n % n % n % n % n % n % n % n % n % n % n % n % Prticipnts with follow-up Prticipnts with fever b (temperture 37.8 C) Mximum temperture (orl) 37.8 C (100 F) C nd 38.9 C (102 F) C nd 39.9 C (103.8 F) C nd 40.9 C (105.6 F) C Percentges were clculted on the bsis of the number of prticipnts with follow-up. Prticipnts with multiple reported tempertures in given rnge were counted only once within tht rnge. b Significntly more boys (P.001) nd girls (P.004) experienced elevted tempertures 37.8 C (100 F) compred with women. pred with boys (15.4%) nd girls (18.6%). Whether this my hve contributed to the differences in the reported incidence of fever between ge groups is uncler. A totl of 11 prticipnts in the 16- to 23-yer-old group becme pregnnt during the course of the study. The outcomes of 8 pregnncies were known: 6 resulted in live birth of norml infnt, nd 2 resulted in fetl loss (1 spontneous bortion nd 1 elective bortion). DISCUSSION This is the first clinicl study to evlute the immunogenicity of qudrivlent HPV vccine in 10- to 15-yerold girls nd boys. The qudrivlent HPV (types 6, 11, 16, nd 18) L1 VLP vccine tht ws tested in this study is designed specificlly to prevent HPV infection nd relted nogenitl lesions, some of which my led to precncerous nd cncerous nogenitl lesions lter in life. One month fter 3-dose vccintion regimen, the type-specific immune responses to the vccine tht were mesured in this study were numericlly greter in both girls nd boys thn in 16- to 23-yer-old femles. Seroconversion for ech of the 4 vccine HPV types ws chieved in 99% of prticipnts in the study. Previous, plcebo-controlled studies demonstrted tht the 4 typespecific virus-neutrlizing ntibody responses tht re induced by this qudrivlent vccine re highly protective ginst persistent infection nd the development of HPV-relted genitl lesions in HPV-nïve women. 9 The results from our study support the bridging of the HPV vccine efficcy dt tht were generted in 16- to 23- yer-old femles who hd immune responses to the vccine, which were similr to those tht we observed in 10- to 15-yer-old girls. 9 HPV infects both femle nd mle individuls. The long-term clinicl sequele, including mortlity, from HPV infection is much more common in women thn it is in men. 3 However, HPV infection in men does cuse significnt morbidity in the form of genitl wrts nd nogenitl cncer. 3,13 Becuse men lso re vectors for trnsmission of HPV infection to women, the suggestion of gender-neutrl vccintion hs been rised. 21 Severl lines of evidence suggest tht this my be n pproprite strtegy. For exmple, previous public helth experience hs shown tht gender-restricted vccintion progrms for other virl diseses re substntilly less effective thn universl vccintion. 22 In ddition, estimtes tht were obtined using mthemticl modeling of the popultion impct of prophylctic HPV vccine indicte tht femle-only vccintion policy likely could be 35% to 40% less efficient thn vccintion of both genders. 23 The robust immune response in 10- to 15-yerold boys in our study supports the concept of genderneutrl vccintion. Studies to evlute the efficcy of this qudrivlent HPV vccine for prevention of infection, genitl wrts, nd nl precncers in men re ongoing. Administrtion of this qudrivlent HPV vccine generlly ws well tolerted in ech ge group, consistent with previous findings from studies in 16- to 23-yer-old femles. 9 Discontinutions nd serious AEs were rre. Although significntly more girls nd boys experienced fevers thn 16- to 23-yer-old femles, most (96.4%) fevers were low grde nd resolved rpidly. Whether the more frequent use of ntirheumtic nd nti-inflmmtory gents (eg, nonsteroidl nti-inflmmtory drugs) by women in the study my hve contributed to the difference in the incidence of fevers between ge groups is uncler. In previous study of monovlent HPV 16 VLP L1 vccine using the sme djuvnt system in 16- to 23-yer-old femles, the incidence of fever ws significntly higher in the vccine group (3.5%) thn in the djuvnt-only group (1.9%), with the highest percentge of subjects experiencing fever in the highest dosge (80 g) group. 8 The incidence of fever tht ws reported in this study seems to be slightly higher thn tht reported for recombinnt heptitis B vccine using similr luminum-contining djuvnt system. 24 The incidence of fever fter vccintion in 16- to 23-yer-old femles in our study ws lower thn reported (16.6%) in PEDIATRICS Volume 118, Number 5, November

10 15- to 25-yer-olds within 7 dys fter dministrtion of bivlent HPV L1 VLP vccine (types 16 nd 18) using different luminum-contining djuvnt (AS04). 25 The choice of the optiml ge rnge for implementtion of immuniztion progrms for new vccine should be bsed on the nturl history of the pthogen ginst which the vccine is trgeted. The pek incidence of HPV infection occurs soon fter sexul debut, nd risk for cquisition is strongly ssocited with the lifetime number of sexul prtners. 3,26 In the United Sttes, 47% of high school students hve engged in sexul intercourse. Of these, 38% nd 7.4% hve reported hving sex before the ge of 15 nd 13, respectively. 27 Erly preneoplstic disese tht is cused by oncogenic HPV types such s 16 nd 18 often presents s low-grde dysplsi. A study tht compred Ppnicolou smer dignoses from to 19-yer-old subjects from helth clinics in northern New Englnd with dignoses from Ppnicolou smers in older ge groups showed tht 10- to 19-yer-olds hve higher percentge of SIL dignoses nd infectious processes thn ny older decde grouping. 11 In our study, lmost 1 in 5 of the 16- to 23-yer-old prticipnts were HPV positive by serology or PCR t dy 1, reflective of sexul ctivity in this popultion. This suggests tht effective public helth progrms to prevent HPV infection nd relted diseses nd ultimtely cervicl cncer through prophylctic immuniztion idelly should trget 10- to 15-yer-old girls nd boys. Acceptnce of such vccine undoubtedly will require intensive eduction efforts on the prt of public helth uthorities, physicins, nd other helth cre providers to inform prents nd ptients of the benefit versus risk of HPV vccintion. 28,29 Combined with cervicl cncer screening progrms, effective vccintion ginst HPV would be expected to prevent infection, reduce virus trnsmission, nd led to dditionl significnt reductions in cervicl cncer incidence rtes nd mortlity A similr pproch to reduce heptocellulr crcinom incidence rtes through universl heptitis B vccintion hs been highly successful. 33 School-bsed immuniztion requirements hve hd mjor impct on driving the high rtes of heptitis B immuniztion in dolescents in the United Sttes. 34,35 Similr pproches my be highly effective for immuniztion of girls nd boys ginst HPV infection. With ny new vccine, the durtion of protection tht is fforded by immuniztion represents legitimte public helth question. This issue is prticulrly relevnt for HPV vccines, becuse women (nd men) remin t risk for HPV-relted disese throughout their lives. 36 In n erlier study, type-specific ntibody responses to this qudrivlent vccine in 16- to 23-yer-old femles were shown to persist through 3.5 yers fter vccintion. 37 Although n immune correlte of protective efficcy hs not been defined, the high postdose 3 nti-hpv responses in girls nd boys re highly suggestive tht long-term protection fter vccintion is likely. The robust immune responses in 16- to 23-yer-olds who were serologic or PCR positive t bseline for 1 or more of the vccine s trgeted HPV types is consistent with the nmnestic response to the HPV L1 ntigen tht ws observed in previous immunogenicity study. 8 This finding suggests tht, if needed, booster vccintions with this vccine lter in life would be highly effective. CONCLUSION Immuniztion of 10- to 15-yer-old girls nd boys with this qudrivlent HPV (types 6, 11, 16, nd 18) L1 VLP vccine resulted in robust nti-hpv type-specific virusneutrlizing ntibody responses. These neutrlizing ntibody responses were sttisticlly noninferior nd observtionlly higher (1.7- to 2.7-fold) thn those observed in popultion of 16- to 23-yer-old femles, group in which the vccine s 100% efficcy for the prevention of HPV-relted disese ws demonstrted previously. 9 Furthermore, these results support the bridging of efficcy dt in 16- to 23-yer-old femles from lrgescle studies which currently re under wy in 10- to 15-yer-old girls. Our findings in boys lend support for the implementtion of gender-neutrl immuniztion using this vccine for the purpose of preventing the widespred morbidity nd mortlity from nogenitl cncer, s well s dysplstic cervicl nd externl genitl lesions, in the generl popultion. Long-term follow-up studies of the qudrivlent HPV (types 6, 11, 16, nd 18) L1 VLP vccine in young dolescents re ongoing. ACKNOWLEDGMENTS Other investigtors who were members of the Protocol 016 Study Group included the following. Asi Pcific: Yuh-Cheng Yng, Tng-Yun Chu, Li-Min Hung, Ricrdo Mnlsts, Sorchi Nityphn, Peter Richmond, Gerrd Win, nd Edith Weisberg; Centrl nd South Americ: Miguel Brrios, Cesr Dm, Rosires Pereir De Andrde, Eugeni Elizondo, An Guzmn, Luis Lombrdi, João Mendonç, Jime Restrepo, Cludio Schvrtsmn, Regin Celi Succi, nd Alberto Vélez; Europe: Jose Mri Bys Rodriguez, Peter Bistoletti, Robert Brownlie, Sbine Cspers, George Cretss, Adrin Drrh, Jose De L Flor Bru, Jvier Diez Domingo, Dvid Dutchmn, Bengt Grnström, Gerd Gross, Thoms Grubert, Fritz Jenicke, Angel Gil de Miguel, Phil Mrzzi, Joseph Monsonego, José Moutinho, Dniel Silv, A. G. J. vn der Zee, nd Elizbeth White; Middle Est: Rchel Bchr nd Michel Feingold; North Americ: Dvid Bernstein, Michell D. Collins-Ogle, Frncisco Diz-Mitom, Mrc Dionne, Dron Ferris, Rolnd Gusprini, Milo Hilty, Mrco Lopez, Tillmn W. McDonld, Susn Nickel, Richrd Rupp, Vyt Seniks, Robert Verdonk, Emmnuel B. Wlter, Jr, nd Dvid M. Whitker. We thnk Frnk J. Tddeo, PhD, Mrk T. Esser, PhD, nd Hviling Li, PhD, who lso contributed to this work BLOCK et l

11 We thnk Hether Sings for ssistnce in the preprtion of this mnuscript. In ddition to the prticipnts who mde this study possible, we thnk the stff t prticipting institutions who were involved with the conduct of this clinicl tril for their dedicted efforts which were essentil for its successful completion. REFERENCES 1. Bosch FX, de Snjose S. Chpter 1: humn ppillomvirus nd cervicl cncer burden nd ssessment of cuslity. J Ntl Cncer Inst Monogr. 2003;31: Nobbenhuis MA, Wlboomers JM, Helmerhorst TJ, et l. Reltion of humn ppillom virus sttus to cervicl lesions nd consequences for cervicl-cncer screening: prospective study. Lncet. 1999;354: Bsemn JG, Koutsky LA. The epidemiology of humn ppillomvirus infections. J Clin Virol. 2005;32(suppl 1):S16 S24 4. Prkin DM, Bry F, Ferly J, Pisni P. Globl cncer sttistics, CA Cncer J Clin. 2005;55: Wiley DJ, Dougls J, Beutner K, et l. Externl genitl wrts: dignosis, tretment, nd prevention. Clin Infect Dis. 2002; 35(suppl 2):S210 S von Krogh G. Mngement of nogenitl wrts (condylomt cumint). Eur J Dermtol. 2001;11: Gbbott M, Cossrt YE, Kn A, Konopk M, Chn R, Rose BR. Humn ppillomvirus nd host vribles s predictors of clinicl course in ptients with juvenile-onset recurrent respirtory ppillomtosis. J Clin Microbiol. 1997;35: Polnd GA, Jcobson RM, Koutsky LA, et l. Immunogenicity nd rectogenicity of novel vccine for humn ppillomvirus 16: 2-yer rndomized controlled clinicl tril. Myo Clin Proc. 2005;80: Vill LL, Cost RL, Pett CA, et l. Prophylctic qudrivlent humn ppillomvirus (types 6, 11, 16, nd 18) L1 virus-like prticle vccine in young women: rndomised double-blind plcebo-controlled multicentre phse II efficcy tril. Lncet Oncol. 2005;6: Skjeldestd FE. Prophylctic qudrivlent humn ppillomvirus (HPV) (Types 6, 11, 16, 18) L1 virus-like prticle (VlP) vccine (Grdsil) reduces cervicl intrepithelil neoplsi (CIN) 2/3 risk [Abstrct LB-8]. In: Proceedings of the 43rd Annul Meeting of the Infectious Disese Society of Americ. Alexndri, VA: Infectious Disese Society of Americ; 2005: Mount SL, Ppillo JL. A study of peditric nd dolescent Ppnicolou smer dignoses in Northern New Englnd. Peditrics. 1999;103: Weinstock H, Bermn S, Ctes W Jr. Sexully trnsmitted diseses mong Americn youth: incidence nd prevlence estimtes, Perspect Sex Reprod Helth. 2004;36: Insing RP, Dsbch EJ, Myers ER. The helth nd economic burden of genitl wrts in set of privte helth plns in the United Sttes. Clin Infect Dis. 2003;36: Woodmn CB, Collins S, Winter H, et l. Nturl history of cervicl humn ppillomvirus infection in young women: longitudinl cohort study. Lncet. 2001;357: Koutsky LA, Ault KA, Wheeler CM, et l. A controlled tril of humn ppillomvirus type 16 vccine. N Engl J Med. 2002; 347: Ault KA, Giulino AR, Edwrds RP, et l. A phse I study to evlute humn ppillomvirus (HPV) type 18 L1 VLP vccine. Vccine. 2004;22: Lowe RS, Brown DR, Bryn JT, et l. Humn ppillomvirus type 11 (HPV-11) neutrlizing ntibodies in the serum nd genitl mucosl secretions of Africn green monkeys immunized with HPV-11 virus-like prticles expressed in yest. J Infect Dis. 1997;176: Oplk D, Lchmn CE, McMullen SA, et l. Simultneous quntittion of ntibodies to neutrlizing epitopes on virus-like prticles for humn ppillomvirus types 6, 11, 16, nd 18 by multiplexed luminex ssy. Clin Dign Lb Immunol. 2003;10: Dis D, Vn Doren J, Schlottmnn S, et l. Optimiztion nd vlidtion of multiplexed luminex ssy to quntify ntibodies to neutrlizing epitopes on humn ppillomviruses 6, 11, 16, nd 18. Clin Dign Lb Immunol. 2005;12: Miettinen O, Nurminen M. Comprtive nlysis of two rtes. Stt Med. 1985;4: Cstellsgue X, Bosch FX, Munoz N, et l. Mle circumcision, penile humn ppillomvirus infection, nd cervicl cncer in femle prtners. N Engl J Med. 2002;346: Bottiger M, Forsgren M. Twenty yers experience of rubell vccintion in Sweden: 10 yers of selective vccintion (of 12-yer-old girls nd of women postprtum) nd 13 yers of generl two-dose vccintion. Vccine. 1997;15: Hughes JP, Grnett GP, Koutsky L. The theoreticl popultionlevel impct of prophylctic humn ppillom virus vccine. Epidemiology. 2002;13: Mrsno LS, West DJ, Chn I, et l. A two-dose heptitis B vccine regimen: proof of priming nd memory responses in young dults. Vccine. 1998;16: Hrper DM, Frnco EL, Wheeler C, et l. Efficcy of bivlent L1 virus-like prticle vccine in prevention of infection with humn ppillomvirus types 16 nd 18 in young women: rndomised controlled tril. Lncet. 2004;364: Decon JM, Evns CD, Yule R, et l. Sexul behviour nd smoking s determinnts of cervicl HPV infection nd of CIN3 mong those infected: cse-control study nested within the Mnchester cohort. Br J Cncer. 2000;83: Grunbum JA, Knn L, Kinchen S, et l. Youth risk behvior surveillnce: United Sttes, MMWR Surveill Summ. 2004; 53: Dvis K, Dickmn ED, Ferris D, Dis JK. Humn ppillomvirus vccine cceptbility mong prents of 10- to 15-yer-old dolescents. J Low Genit Trct Dis. 2004;8: Olshen E, Woods ER, Austin SB, Luskin M, Buchner H. Prentl cceptnce of the humn ppillomvirus vccine. J Adolesc Helth. 2005;37: Snders GD, Tir AV. Cost-effectiveness of potentil vccine for humn ppillomvirus. Emerg Infect Dis. 2003;9: Kulsingm SL, Myers ER. Potentil helth nd economic impct of dding humn ppillomvirus vccine to screening progrms. JAMA. 2003;290: Goldie SJ, Kohli M, Grim D, et l. Projected clinicl benefits nd cost-effectiveness of humn ppillomvirus 16/18 vccine. J Ntl Cncer Inst. 2004;96: Lvnchy D. Heptitis B virus epidemiology, disese burden, tretment, nd current nd emerging prevention nd control mesures. J Virl Hept. 2004;11: Tung CS, Middlemn AB. An evlution of school-level fctors used in successful school-bsed heptitis B immuniztion inititive. J Adolesc Helth. 2005;37: Middlemn AB. Rce/ethnicity nd gender disprities in the utiliztion of school-bsed heptitis B immuniztion inititive. J Adolesc Helth. 2004;34: Rousseu MC, Pereir JS, Prdo JC, Vill LL, Rohn TE, Frnco EL. Cervicl coinfection with humn ppillomvirus (HPV) types s predictor of cquisition nd persistence of HPV infection. J Infect Dis. 2001;184: Mo C, Koutsky LA, Ault KA, et l. Efficcy of humn ppillomvirus-16 vccine to prevent cervicl intrepithelil neoplsi: rndomized controlled tril. Obstet Gynecol. 2006;107:18 27 PEDIATRICS Volume 118, Number 5, November