In this dcument: Summary Key Messages FluView Activity Update LAIV Effectiveness and Vaccinatin f Children H3N2 Match and Vaccinatin Vaccine Supply Summary Key Messages This week s FluView reprt indicates that seasnal influenza activity remains lw, thugh there are early signs that activity is increasing. Flu activity is expected t increase in the cming weeks. Surveillance shws that mst circulating viruses s far this seasn are influenza A (H3N2) and influenza B viruses. There is very little circulatin f influenza A (H1N1) s far. (See the FluView Activity Update belw.) While mst f the viruses analyzed in recent mnths are like the 2014-2015 vaccine viruses, there are sme influenza A (H3N2) viruses that are antigenically drifted frm the H3N2 virus cmpnent used in this seasn s vaccine. (See sectin "H3N2 Match and Vaccinatin.") CDC recmmends a three-prnged apprach t fighting flu: First, take time t get a flu vaccine. Secnd, take everyday preventive actins like cvering cughs and sneezes, staying away frm sick peple and washing yur hands ften t help stp the spread f respiratry viruses like flu, respiratry syncytial virus (RSV), rhinvirus and entervirus D68. Third, antivirals shuld be used as recmmended as a secnd line f defense t treat flu illness. Annual flu vaccinatin is the first and mst imprtant step in prtecting against flu and its ptentially serius cmplicatins. Getting vaccinated befre influenza activity begins helps prtect yu nce the flu seasn starts in yur cmmunity. It takes abut tw weeks after vaccinatin fr the bdy s immune system t fully respnd and fr yu t be prtected. Peple wh have nt been vaccinated yet this seasn shuld get vaccinated nw. 1
Patients shuld get immunized with whatever vaccine is immediately available and indicated. Influenza vaccinatin shuld nt be delayed t prcure a specific vaccine preparatin. The HealthMap Vaccine Finder can be used t lcate vaccine. Yu need this seasn s influenza vaccine fr ptimal prtectin against the flu. (Immunity frm vaccinatins declines ver time.) While hw well the flu vaccine wrks can vary, vaccinatin has been shwn t reduce flu illnesses, dctrs' visits, and missed wrk and schl due t influenza, as well as prevent flu-related hspitalizatins and deaths. Flu vaccinatin can help prtect peple wh are at greater risk f getting seriusly ill frm flu, like lder adults, peple with chrnic health cnditins and yung children (especially infants yunger than 6 mnths ld wh are t yung t get vaccinated). Seven influenza vaccine manufacturers have prjected that as many as 151 millin t 156 millin dses f influenza vaccine will be available fr use in the United States during the 2014-2015 influenza seasn. As f Octber 31, 132.2 millin dses f influenza vaccine had been distributed in the United States, which means that mre vaccine has been distributed than at this time last seasn. There are several flu vaccine ptins available fr the 2014-2015 flu seasn. Flu shts made t prtect against three different flu viruses (called trivalent vaccines) are available this seasn. There als are flu shts and nasal spray vaccines made t prtect against fur different flu viruses (called quadrivalent vaccines). Abut half f the ttal influenza vaccine supply will be quadrivalent, while the ther half will be trivalent. There is sme evidence t suggest that the nasal spray vaccine may nt prtect children against H1N1 viruses during the 2014-2015 seasn. (See the sectin LAIV Effectiveness and Vaccinatin f Children belw.) CDC recmmends that parents shuld get their children immunized with whatever vaccine is immediately available and indicated. Sme children 6 mnths thrugh 8 years f age getting vaccinated fr this first time will require tw dses f flu vaccine. The secnd dse shuld be given at least 28 days after the first dse. Yur child s dctr r ther health care prfessinal can tell yu whether tw dses are recmmended fr yur child.
And remember that influenza antiviral drugs are a secnd line f defense t treat flu illness. Antiviral drugs can treat flu illness and prevent serius flu cmplicatins. These drugs wrk best when started sn after influenza symptms begin (within 2 days), but persns with high-risk cnditins can benefit even when antiviral treatment is started after the first tw days f illness. A dctr r health care prfessinal can determine if a patient needs flu antiviral drugs. Influenza vaccinatin and rapid antiviral treatment are especially imprtant fr peple at high risk fr flu cmplicatins. Peple at high risk fr serius flu cmplicatins include: peple with underlying chrnic medical cnditins such as asthma, diabetes, heart disease, r neurlgical cnditins; pregnant wmen; thse yunger than 5 years r lder than 65 years f age; r anyne with a weakened immune system. A full list f high risk factrs is available at http://www.cdc.gv/flu/abut/disease/high_risk.htm. As always, peple wh are at high risk fr influenza cmplicatins shuld see a health care prfessinal prmptly if they get flu symptms, even if they have been vaccinated this seasn. Mre infrmatin abut everyday preventive actins that help fight flu is available at http://www.cdc.gv/flu/prtect/habits.htm. Flu symptms include fever, cugh, sre thrat, runny r stuffy nse, muscle r bdy aches, headache, chills and fatigue. FluView Activity Update Accrding t this week s FluView reprt, verall seasnal flu activity remains lw acrss the United States. Increases in flu activity are expected in the cming weeks. Belw is a summary f the key flu indicatrs fr the week ending Nvember 1, 2014: Fr the week ending Nvember 1, the prprtin f peple seeing their health care prvider fr influenza-like illness (ILI) was belw the natinal baseline. All 10 U.S. regins reprted ILI activity belw regin-specific baseline levels. Puert Ric experienced high ILI activity. One state (Luisiana) experienced lw ILI activity. New Yrk City and 49 states experienced
minimal ILI activity. The District f Clumbia did nt have sufficient data t calculate an activity level. ILI activity data indicate the amunt f flulike illness that is ccurring in each state. Guam reprted widespread gegraphic influenza activity. Tw states (Alaska and Flrida) reprted reginal influenza activity. Puert Ric and three states (Cnnecticut, Oregn, and Texas) reprted lcal activity. The District f Clumbia and 40 states reprted spradic influenza activity. Five states (Idah, Missuri, New Hampshire, Nrth Carlina, and Rhde Island) reprted n influenza activity. The U.S. Virgin Islands did nt reprt. Gegraphic spread data shw hw many areas within a state r territry are seeing flu activity. Data regarding influenza-assciated hspitalizatins fr the 2014-2015 influenza seasn is nt yet available fr this seasn. The prprtin f deaths attributed t pneumnia and influenza (P&I) based n the 122 Cities Mrtality Reprting System is belw the epidemic threshld. N influenza-assciated pediatric deaths were reprted t CDC during the week ending Nvember 1. One influenza-assciated pediatric death has been reprted fr the 2014-2015 seasn and ccurred during the week ending Octber 4, 2014. Natinally, the percentage f respiratry specimens testing psitive fr influenza viruses in the United States during the week ending Nvember 1 was 6.0%. Fr the mst recent three weeks, the reginal percentage f respiratry specimens testing psitive fr influenza viruses ranged frm 1.2% t 9.3%. Influenza A (H3N2), 2009 influenza A (H1N1), and influenza B viruses h have been identified mst cmmnly in the United States this seasn. Very few H1N1 viruses have been reprted. During the week ending Nvember 1, 394 (78.2%) f the 504 influenza-psitive tests reprted t CDC were influenza A viruses and 110 (21.8%) were influenza B viruses. Of the 121 influenza A viruses that were subtyped, 99.2% were H3 viruses and 0.8% were 2009 H1N1 viruses. CDC has antigenically characterized 10 influenza A (H3N2) viruses cllected in the United States since Octber 1, 2014. Seven (70%) f the 10 influenza A (H3N2) viruses tested have been characterized as A/Texas/50/2012-like. This is the influenza A (H3N2) cmpnent f the 2014-2015 Nrthern Hemisphere influenza vaccine. Three (30%) H3N2 viruses were antigenically
similar t A/Switzerland/9715293/2013, the H3N2 virus selected fr the 2015 Suthern Hemisphere influenza vaccine. Since Octber 1, 2014, CDC has tested six influenza A (H3N2) fr resistance t neuraminidase inhibitrs (seltamivir and zanamivir). All six influenza A (H3N2) viruses shwed susceptibility t bth seltamivir and zanamivir. The neuraminidase inhibitrs seltamivir and zanamivir are currently the nly recmmended influenza antiviral drugs. As in recent past seasns, high levels f resistance t the adamantanes (amantadine and rimantadine) cntinue t persist amng 2009 influenza A (H1N1) and A (H3N2) viruses. Adamantanes are nt effective against influenza B viruses. FluView is available and past issues are archived n the CDC website. Nte: Delays in reprting may mean that data changes ver time. The mst up t date data fr all weeks during the 2014-2015 seasn can be fund n the current FluView. LAIV Effectiveness Last Seasn and Vaccinatin f Children This Seasn Since 2008, ACIP and CDC have recmmended that all children 6 mnths and lder (with rare exceptins) receive influenza vaccine annually, using any licensed age-apprpriate vaccine. During the summer f 2014, ACIP and CDC recmmended that beginning during the 2014-2015 influenza seasn, live attenuated influenza vaccine (LAIV, r the "nasal spray vaccine") shuld be used fr healthy children 2 thrugh 8 years f age when immediately available and when there are n cntraindicatins r precautins against getting that vaccine. This decisin was based n previus data shwing that LAIV ffered superir prtectin against influenza virus infectin cmpared t IIV in yung children. Hwever recently available CDC analyses shwed that there was n measurable effectiveness fr LAIV against influenza A (H1N1) amng children enrlled in the study last seasn. There were nt enugh cases f infectin with H3N2 r B viruses t calculate vaccine effectiveness against thse viruses in children last seasn. The reasns behind the lack f effectiveness against H1N1infectins fr LAIV during the 2013-14 seasn are nt fully understd.
It is pssible that results may be specific t the H1N1 cmpnent f LAIV. Influenza H1N1 viruses predminated during the 2013-2014 seasn fr the first time since their emergence in 2009 when they caused a pandemic. It als is pssible thugh less likely that there is an unidentified issue with the study methds r analysis plan fr measuring LAIV vaccine effectiveness. The 2013-2014 seasn LAIV VE estimates against H1N1 fr children suggest that LAIV may nt prtect against H1N1 viruses during the 2014-2015 seasn because the same H1N1 vaccine virus frm the 2013-2014 vaccine is included in the 2014-2015 vaccine. Hwever, the nasal spray vaccine cntinues t be a recmmended ptin fr vaccinatin because: All LAIV is designed t prtect against fur different influenza viruses: Influenza A (H1N1), A (H3N2) and tw influenza B viruses. Surveillance shws that there is substantially mre circulatin f influenza A (H3N2) and B viruses and very little circulating H1N1 s far; LAIV has been shwn t ffer gd prtectin against influenza A (H3N2) and influenza B viruses in the past; LAIV may ffer better prtectin than IIV against antigenically drifted viruses that may circulate this seasn; and Vaccine prviders have received their vaccine fr the 2014-2015 seasn and have likely administered a gd prprtin f it. Peple wh have nt been vaccinated yet this seasn shuld get vaccinated nw. Parents shuld seek t get their children immunized with whatever vaccine is immediately available and indicated. Influenza vaccinatin shuld nt be delayed t prcure a specific vaccine preparatin. The HealthMap Vaccine Finder can be used t lcate vaccine. Children needing ne dse f vaccine this seasn wh gt the nasal spray vaccine are cnsidered fully vaccinated and d nt need t be revaccinated. Children needing tw dses f vaccine this seasn wh have nly gtten ne dse can get either the nasal spray vaccine r the flu sht as their secnd dse, whatever is immediately available.
See the CDC statement, CDC Statement n LAIV Effectiveness and Vaccinatin f Children, at: http://www.cdc.gv/flu/news/nasal-spray-effectiveness.htm. H3N2 Match and Vaccinatin Surveillance f influenza viruses shws that sme f the influenza A (H3N2) viruses cllected dmestically and internatinally in recent mnths are antigenically different ( drifted ) frm the H3N2 vaccine cmpnent. An Octber 3 Mrbidity and Mrtality Weekly Reprt "Influenza Update" reprted that f 141 influenza A (H3N2) viruses cllected glbally between May 18-September 20, 2014 and characterized by CDC, 69 (49%) were antigenically similar t A/Texas/50/2012, the influenza A (H3N2) cmpnent f the 2014-2015 influenza vaccine fr the Nrthern Hemisphere. Only 10 A (H3N2) viruses cllected in the United States since Octber 1, 2014 have been characterized s far this seasn. Seven f these (70%) are like the A (H3N2) vaccine virus, 3 (30%) have been characterized as A/Switzerland/9715293/2013, an antigenic variant virus which has been selected fr the 2015 Suthern Hemisphere influenza vaccine. A/Switzerland viruses were first cllected in March 2014, after the vaccine viruses fr the Nrthern Hemisphere vaccine had already been made in February. Initially, A/Switzerland viruses appeared nly spradically, but became mre cmmn ver the summer. Hw well the vaccine wrks depends in part n the match between vaccine viruses and circulating flu viruses. If the viruses are well-matched, vaccine effectiveness tends t be higher. If they are nt well-matched, vaccine effectiveness can be lwer. If drifted influenza A (H3N2) viruses circulate bradly in the United States this seasn, this culd translate int reduced vaccine effectiveness against circulating H3N2 viruses. Even when drifted viruses are fund t be circulating, CDC cntinues t recmmend influenza vaccinatin because: Studies have shwn evidence that seasnal influenza vaccinatin can smetimes induce antibdies and/r T cells capable f crss-reacting with antigenically distinct viruses. This is called crss-prtectin. While vaccine effectiveness may be reduced, the vaccine can still ffer prtectin.
Mre than ne type r subtype f influenza usually circulates during a single seasn and flu vaccines prtect against three r fur different influenza viruses, depending n which vaccine is given. Flu vaccinatin cntinues t ffer the best prtectin against influenza infectin, even when there are sme antigenically drifted viruses circulating in the cmmunity. Influenza antiviral treatment is an imprtant secnd line f defense t treat flu illness in the event f infectin. Visit the CDC website fr infrmatin abut hw antiviral medicatins can be used t prevent r treat influenza when influenza activity is present in yur cmmunity. Further, everyday actins like cvering yur cugh, staying away frm sick peple and washing yur hands ften can help prevent the spread f respiratry viruses like the flu. Vaccine Effectiveness, General Influenza viruses are cnstantly changing they can change frm ne seasn t the next r they can even change within the curse f the same seasn. This kind f gradual change is called antigenic drift. It is because f drift that the cmpsitin f the flu vaccine is reviewed annually and updated as needed t keep up with circulating viruses. Each year experts pick which viruses t include in the vaccine many mnths in advance (usually February) in rder fr vaccine t be prduced and delivered in time fr the upcming flu seasn. Because flu viruses are cnstantly changing and it takes a lng time t manufacture flu vaccine, there is always the pssibility f a sub-ptimal match between circulating viruses and the viruses in the vaccine. While a less than ptimal virus match can reduce the vaccine s effectiveness, vaccinatin can still prtect enugh t make illness milder and prevent flu-related cmplicatins. Such prtectin is pssible because antibdies created thrugh vaccinatin with ne strain f influenza viruses will ften crss-prtect against different influenza viruses.
Vaccine Supply Seven influenza vaccine manufacturers have prjected that as many as 151 millin t 156 millin dses f influenza vaccine will be available fr use in the United States during the 2014-2015 influenza seasn. This prjectin is similar t that prvided by manufacturers befre influenza vaccine distributin began fr this year, with the difference being that the high end f the range is reduced by apprximately 4 millin dses. Of the verall flu vaccine supply prjected fr the 2014-2015 seasn, manufacturers estimate that 76 millin dses will be available as quadrivalent flu vaccines. Of the ttal quadrivalent flu vaccine supply, as many as 18 millin dses f the nasal spray influenza vaccine (LAIV) have been prjected by the manufacturer t be available. During September, sme manufacturers, including thse wh develp flu vaccines apprved fr children in the United States, reprted delays in shipments that were riginally anticipated fr early fall. These early seasn shipping delays impacted certain vaccine prducts mre than thers, thus impacting sme prviders mre than thers. We understand that this can be very frustrating fr prviders and their patients wh experienced these delays. Despite these early seasn shipping delays, hwever, apprximately 85% f the ttal dses prjected fr the seasn were distributed by the end f Octber. Remaining flu vaccine dses are anticipated t be distributed during the mnth f Nvember. As f Octber 31, 2014, manufacturers reprted having shipped 132.2 millin dses f flu vaccine. Sme pints t keep in mind: All nasal spray flu vaccine ffered during the 2014-2015 seasn will be quadrivalent vaccine. Bth quadrivalent and trivalent flu shts will be available. Dn t delay getting a flu vaccine if yu want a quadrivalent vaccine and it is nt available. Mst f the flu vaccine ffered this year will be trivalent. The imprtant thing is t get vaccinated against the flu. Mre quadrivalent flu vaccine is expected t be available during future seasns.
Fr the latest infrmatin n flu vaccine supply, including prjectins and dses distributed, visit http://www.cdc.gv/flu/prfessinals/vaccinatin/vaccinesupply.htm.