Committee on Infectious Diseases. following administration of pertussis vaccine have led to some changes in recommendations

Transcription

1 Committee on Infectious Diseases Pertussis Vaccine The Red Book, as the Report of the Committee on Infectious Diseases has come to be known, is not a static document, but is subject to frequent revision. Not only does each edition contain new information available to the Committee, but between editions the Committee communicates further changes to the medical profession via Pediatrics. These communications constitute Updates to the Red Book. As everyone knows, scientific information proliferates exponentially, and so the Updates have ap- peared more frequently in recent years. The Update that follows concerns pertussis vaccine, and therefore, it supplements information in the 1982 edition of the Red Book. To place it in context, the entire Red Book section on Pertussis (pp 198 to 22) should be re- viewed, as well as the general sections on immunization, particukirly the section on Informed Consent (p 4) and the section on Vaccine Dose (p 1). Like many preventable childhood diseases, pertussis is now infrequently reported in this country. Although more than 2, cases were reported annually in the 193s before pertussis vaccine was introduced, only about 2, cases are now recognized each year. The success of the vaccine has resulted in the remarkable decline ofa formerly feared illness. As the incidence of the disease has declined, adverse reactions attributed to pertussis vaccine have re- ceived greater attention and prominence. In the United Kingdom, following Professor G. T. Stew- art 5 alarming reports of brain damage due to pertussis vaccine, immunization rates feliprofoundly, and as a result widespread outbreaks of pertussls began to occur. In this country as well, there is public recognition that the pertus- sis vaccine produces higher reaction rates than other vac- cines, and in our concern with the reactions there is a danger that we may forget thatprrtussis, the disease, produces ten times the rate of braindarnage asp.ussis, the vaccine. Until a better vaccine is available, the risk- benefit ratio has been repeatedly shown to favor the im- munization of children with the presently available per- tussis vaccine (Hinman AR, Koplan JP: Pertussis and I pertussis vaccine: Re-analysis of benefits, risks and costs.! JAMA, in press 1984). We wish to avoid the resurgence of I pertussis outbreaks that occurred in Britain when the level I of vaccine utilization was reduced. But neither do we want to see pertussis vaccine given when prudence and the Red Book Committee suggest it be I withheld: when a previous dose resulted in a convulsion,! encephalitis, focal neurologic signs, or colk.ipse. Nor should I infants who experience excessive somnolence, excessive screaming (persistent crying or screaming for 3 or more PEDIATRICS (ISSN 31 45). Copyright 1984 by the American Academy of Pediatrics. hours duration), or temperature more than 15#{176}F (4.5#{176}C) receive additional doses of vaccine. Parents, and pediatricians alike, together with the Academy, the federal health agencies, the Congress and vaccine producers, all look forward to the availability of a safer and even more effective pertussis vaccine. Until that time, the Academy urges that parents be informed about the vaccine we have and the disease it is more than 8% effective in preventing, and that infants and children continue to receive the vaccine, on schedule, when there are no contraindications to its use. PAUL F. WEHRLE, MD President, American Academy of Pediatrics A review of the current data on the frequency and severity of pertussis and also of reactions occurring following administration of pertussis vaccine have led to some changes in recommendations for immunization with pertussis vaccine. Continued efforts to immunize those who should receive vaccine are essential as pertussis produces significant morbidity and may even be fatal; it is particularly severe in those who are unimmunized. The curtailment of pertussis immunization has resulted in epidemics in some countries.2 Infants with a previous personal history of seizures appear to be more likely to have a convulsion following receipt of pertussis vaccine.3 There is no convincing evidence to suggest that these isolated seizures produce permanent neurologic damage or aggravate existing neurologic conditions.45 Although the risk of vaccine-related seizures in these children is small, the likelihood of contracting pertussis for most of these children in the United States at this time is also small. It may be prudent, therefore, to defer immunization of these children in order to eliminate the possibility of their experiencing postimmunization seizures. The decision to defer immunization should be reviewed at each subsequent office or clinic visit, evaluating changes in risk of exposure and the likelihood of seizures following immunization. Downloaded from by guest on September 12, 218 PEDIATRICS Vol. 74 No. 2 August

2 INCREASED RISK OF CONVULSION FOLLOWING VACCINE Children Who Should Not Receive Additional Doses of Pertussis-Containing Vaccine Children who have a seizure within 48 hours following the receipt of a pertussis-containing vaccine, eg, DTP, should not receive additional doses of pertussis-containing vaccines. Because additional doses of pertussis vaccine are contraindicated, the outcome of reimmunization cannot be predicted. Some of these seizures may be due to fever caused by intercurrent illnesses4 or fever induced by the pertussis component of the vaccine. The risk of first seizures following pertussis vaccine appears to be approximately 1/1,75 immunizations.5 Children Who Might Have Immunization Deferred 1. Children who have had a personal history of convulsion at any time appear to have an increased risk of convulsions following receipt of pertussiscontaining vaccines. A recent study of reports submitted to the Centers for Disease Control revealed a sixfold greater frequency of personal history of prior seizure in children who had a seizure following receipt of DTP as compared with children who had local reactions or other non-neurologic adverse reactions after pertussis vaccine.3 The exact frequency of seizures following DTP in children who have had a previous personal history of non-pertussis-vaccine-associated seizure is unknown. 2. Children with certain neurologic conditions (eg, tuberous sclerosis, certain inherited metabolic defects, and other conditions), that might predispose to seizures may be at increased risk of convulsions following receipt of pertussis-containing vaccines. Prematurity per se is not believed to increase the risk of seizures following immunization. Additional studies are required of certain categories of premature infants, eg, those with intracranial bleeding of varying severity. Children with developmental delay or cerebral palsy without other evidence that they have a predisposition to seizures ordinarily would not be considered to be at increased risk of seizures following pertussis immunization. CONDITIONS OF UNCERTAIN RISK OF CONVULSION FOLLOWING IMMUNIZATION It has been suggested that the risk of convulsions following receipt of pertussis vaccine is increased if there is a family member who has a nonfebrile seizure disorder,3 or if a sibling has had a seizure following receipt of a pertussis-containing vaccine. Because of methodologic problems with the study, it is not known whether the risk of postimmunization seizures is significantly greater in these persons than in the general population. For this reason the identification of these conditions in family members of the vaccinee is not considered to be reason to defer pertussis immunization at the present time. RISK OF EXPOSURE TO PERTUSSIS 1. Infants who attend day care centers or participate in other activities in which there is increased close contact with other young infants are at greater risk of being infected with a variety of infectious agents that are endemic to their setting or prevalent in the community. 2. Infants and children enrolled in programs or who reside in institutions for the neurologically impaired may be in an environment in which a significant proportion of the others with whom they are in contact are not adequately protected against pertussis.6 If these children should become infected, some believe they may suffer greater morbidity than would normal children. Thus the introduction of pertussis into such a group might lead to both increased spread and more severe illness. 3. There is a significant risk of exposure to pertussis in many underdeveloped countries, in many parts of the western hemisphere including parts of Canada and some developed countries, eg, England, Japan, and others where immunization programs have been less than otpimal. 4. At the present time, the risk of exposure to pertussis in most areas in the United States is relatively low. At times, epidemics of pertussis may occur in certain areas, eg, parts of Oklahoma in i983, and the risk of exposure may be significantly increased. IMMUNIZATION SCHEDULES 1. Pertussis vaccine is oridinarily given in cornbination with tetanus and diphtheria toxoids (DTP) starting at 2 months of age. Additional doses of DTP are recommended at 4, 6, and 18 months, and a final dose between 48 and 84 months of age. In epidemic situations, immunization may be started as early as 2 weeks of age, and the first three doses can be given as frequently as 4 weeks apart. 2. In children who are to have pertussis immunization deferred, pediatric diphtheria, tetanus toxoid (DT), should be given in lieu of DTP. If started after 1 year of age, two rather than three doses are to be given followed by a third dose 1 year later. Polio vaccine should be given according to the regularly recommended schedule. 34 PERTUSSIS VACCINE Downloaded from by guest on September 12, 218

3 Reassessment of Children for Whom Immunization Was Deferred 1. Immunization after infancy of those in whom. it has been deferred is of considerable value. Al- though pertussis is most severe in younger infants, it may cause significant illness in older infants, children, and adults. School epidemics have been described. Immunization also may be valuable in decreasing the likelihood of infection of younger siblings. 2. Deferred pertussis immunization should be reevaluated at each office or clinic visit. Changes in risk of exposure, eg, enrollment in day care or other programs, travel, epidemics of pertussis, and others should be assessed. A reevaluation of the child s risk of seizures based on observation of frequency of seizures or a clearer understanding of seizure etiology may lead to a decision to immunize! against pertussis. Pertussis vaccine should be given if there is no need to immunize against diphtheria and tetanus. It can be obtained only from the Michigan State Department of Health, Biologics! Division, P Box 335, Lansing, MI Three! doses of pertussis vaccine are recommended for the I primary immunizing series. A fourth dose is given! 1 year following the third dose. Contraindications for Pertussis Immunization Pertussis immunization is contraindicated for! those who have any of the following reactions after administration of a pertussis-containing vaccine: (1) a severe neurologic reaction; (2) persistent un- consolable screaming for three hours or more; (3) a! hyporesponsive, shock-like state; (4) temperature of 4.5#{176}C (15#{176}F) or greater, unexplained by an-! other cause within 24 hours following immuniza- tion; (5) a convulsion within 48 hours following immunization; or (6) an allergic reaction to the : vaccine. FRACTIONAL DOSES OF PERTUSSIS VACCINE 1. Giving smaller than recommended doses to those with contraindications cannot be recommended. Administration of mu IttThimaller doses increases the risk of association with untoward events that may be unrelated to the vaccine. There is no evidence, moreover, that smaller doses will decrease the likelihood of contraindicated reactions. Indeed one child who had a convulsion following DTP immunization may have had a similar reaction to a subsequent fractional dose. 2. Giving smaller doses at different visits will reduce local reactions but may also reduce serologic response.8 Whether children who receive multiple small doses of pertussis vaccine are adequately protected against disease is unknown. DEVELOPMENT OF NEW PERTUSSIS VACCINE Work is in progress toward the development of an improved pertussis vaccine. Development of a new vaccine, or the administration of DT rather than DTP will not eliminate temporally associated but etiologically unrelated events that occur at the ages when children ordinarily receive their immunizations. It is unlikely that a significantly better vaccine will be available for many years. Continued immunization with the current vaccine of children for whom it is not contraindicated is strongly recommended. COMMITTEE ON INFECTIOUS DISEASES, Philip A. Brunell, MD, Chairman James W. Bass, MD Robert S. Daum, MD William B. Gamble, Jr, MD G. Scott Giebink, MD Caroline Breese Hall, MD Georges Peter, MD Stanley A. Plotkin, MD Liaison Representatives Alan R. Hinman, MD William S. Jordan, Jr, MD John C. Petricciani, MD David Scheifele, MD AAP Section Liaison John A. Anderson, MD REFERENCES 1. Pertussis surveillance, MMWR 1982;31: Robinson RJ: The whooping-cough immunisation controversy. Arch Di.s Child 1981;56: Adverse Events Following Immunization: Surveillance: Report No. 1, Atlanta, Centers for Disease Control, in press Hirtz DG, Nelson KB, Ellenberg JH: Seizures following childhood immunizations. J Pediatr 1983;12: Cody CL, Baraff U, Cherry JD, et a!: Nature and rates of adverse reactions associated with DTP and DT immunizations in infants and children. Pediatrics 1981;68: Miles RN, Hosking GP: Pertussis: Should we immunise neurologically disabled and developmentally delayed children? Br Med J 1983;285: Pertussis outbreak-oklahoma. MMWR 1984;33:2-1O 8. Baraff U, Cody CL, Cherry JD: DTP-associated reactions: An analysis by injection site, manufacturer, prior reactions, and dose. Pediatrics 1984;73:31-36 Downloaded from AMERICAN by guest on ACADEMY September 12, OF 218 PEDIATRICS 35

4 Pertussis Vaccine Pediatrics 1984;74;33 Updated Information & Services Permissions & Licensing Reprints including high resolution figures, can be found at: Information about reproducing this article in parts (figures, tables) or in its entirety can be found online at: Information about ordering reprints can be found online: Downloaded from by guest on September 12, 218

5 Pertussis Vaccine Pediatrics 1984;74;33 The online version of this article, along with updated information and services, is located on the World Wide Web at: Pediatrics is the official journal of the American Academy of Pediatrics. A monthly publication, it has been published continuously since Pediatrics is owned, published, and trademarked by the American Academy of Pediatrics, 141 Northwest Point Boulevard, Elk Grove Village, Illinois, 67. Copyright 1984 by the American Academy of Pediatrics. All rights reserved. Print ISSN: Downloaded from by guest on September 12, 218