Rethinking contraindications to vaccination

Children are currently being denied vaccines for inappropriate reasons

MJA 1998; 168: 476-477
See also Bond et al. and Andrews et al.
 

The most recent edition of the National Health and Medical Research Council's Australian immunisation handbook gives very clear guidelines about the contraindications to vaccination with pertussis vaccine and measles-mumps-rubella vaccine (MMR).1 This was necessary because many children have been denied these vaccines for inappropriate reasons, such as previous reactions at the injection site, fever or irritability after pertussis vaccine, or a history of egg allergy (for ruling out measles vaccine).2 The guidelines now recommend only two absolute contraindications to pertussis-containing vaccines -- encephalopathy or severe allergic reaction following a previous dose. However, over the past two years the Australian Childhood Immunisation Register has recorded that more than 32 000 doses of combined diphtheria-tetanus vaccine (CDT) have been administered to children in place of diphtheria- tetanus-pertussis vaccine (DTP), suggesting that doctors are not following this advice. In addition, based on substantial local and overseas evidence, the guidelines also recommend that "egg allergy, even anaphylactic egg allergy, is NOT a contraindication to immunisation with measles vaccine or MMR".1,3 The previous concept that egg allergy contraindicated MMR came from the manufacturers' product insert and was based on the incorrect assumption that, as it was cultured in chick fibroblasts, it could contain egg antigens. It is likely that inappropriate caution about vaccinating children with previous reactions to pertussis vaccine has been partly responsible for the re-emergence of pertussis over the past four years.4 There were more than 10 000 notified pertussis cases in Australia in 1997, and nine deaths between October 1996 and November 1997.5 Similarly, unnecessary caution about children with egg allergy may have contributed to our measles outbreaks.6 In this issue of the Journal, Andrews and colleagues show how children with previous severe reactions to pertussis vaccine (convulsions, apnoea, hypotonic-hyporesponsive episodes, high fever and persistent screaming) were safely vaccinated in a special clinic at The Canberra Hospital.7 This clinic was the first of a number of similar services now operating or about to begin operating in other centres, including Sydney, Melbourne, and Adelaide. Information about these services is available from State and Territory health departments, which have encouraged their establishment. These clinics plan to collaborate and share expertise nationally. What does this mean for the doctors and nurses who provide routine vaccinations? It means that they should be confident about the guidelines in the Immunisation handbook.1 Children with previous mild to moderate non-anaphylactic reactions (including persistent screaming and high fever) can be vaccinated (with routine precautions) by their usual vaccine provider. Paracetamol should be given prophylactically (15 mg/kg body weight for each oral dose1) to reduce the rate of local and systemic reactions to vaccines containing the whole-cell pertussis component. Children who have had severe reactions (prolonged hypotonic-hyporesponsive episodes and seizures, each seen about once every 2000 doses of whole-cell pertussis vaccine) can also be vaccinated safely,8,9 but may need to be assessed and vaccinated at (or, for rural families, in consultation with) a special clinic. The few children with a history of anaphylaxis following vaccination -- said to occur in about 1/50 000 doses of DTPw (diphtheria-tetanus-whole-cell pertussis vaccine)10 -- and children with underlying medical conditions who may be at special risk (eg, severe neurological disorders) should also be referred for assessment and advice. A new vaccine containing acellular pertussis components (DTPa -- diphtheria-tetanus-acellular-pertussis) is now approved in Australia for use in infants and children. It is funded nationally for the doses given to children aged 18 months and 4 to 5 years, and by some States and Territories (at present South Australia and the Northern Territory) for the three infant doses. Acellular vaccines are associated with a significantly lower rate of reactions at the injection site, hypotonic-hyporesponsive episodes, convulsions and screaming.11 For this reason they are recommended for infants who have had a previous severe reaction to DTPw. Acellular vaccines were not available when The Canberra Hospital clinic was established, so DTPw was used and found satisfactory. Since the use of acellular vaccines for the fourth and fifth doses (at 18 months and 4 to 5 years) in the United States, the rate of serious side effects after vaccination has been reduced by 60% to 70%.12 The availability of acellular pertussis vaccine should remove any need for general practitioners to use CDT vaccine. In Australia, as in many other countries, the States and Territories have established a formal reporting system for vaccine adverse events. Providers report vaccine reactions either to their local public health units or to central disease control units of State or Territory health departments. This information is then supplied to the national Serious Adverse Events Following Vaccination Surveillance Scheme (SAEFVSS), which commenced in March 1995 and is run by the National Centre for Disease Control in Canberra.13 Many vaccine providers do not realise that they should be reporting serious reactions -- so, for example, the number of hypotonic-hyporesponsive episodes being reported is less than would be expected from vaccine trials in which there is active follow-up.11 Other forms of adverse event surveillance should now be used to supplement the SAEFVSS. This would include transmission of data to the SAEFVSS from the special clinics and from hospital admissions, or active surveillance, through such initiatives as the Australian Paediatric Surveillance System, of specific rare serious events. These measures would help make the system more sensitive,14,15 and this would further reassure both providers and the public about the good safety record of the vaccines used in the current childhood immunisation schedule. We must conclude from The Canberra Hospital clinic report that most children with previous severe reactions can be safely vaccinated and that no child should be deprived of pertussis or MMR vaccines without consultation with a specialist advisory service. Margaret A Burgess Director Peter B McIntyre Deputy Director Timothy C Heath Research Fellow National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Royal Alexandra Hospital for Children Westmead, and The University of Sydney, Sydney, NSW National Health and Medical Research Council. The Australian immunisation handbook. 6th ed. Canberra: AGPS, 1997. MacIntyre CR, Nolan T. Attitudes of Victorian immunisation providers to pertussis vaccine. Med J Aust 1994; 161: 293-294. Aickin R, Hill D, Kemp A. Measles immunisation in children with allergy to egg. BMJ 1994; 309: 223-225. Burgess MA, McIntyre PB, Heath TC. Pertussis re-emerging: who is responsible? Aust N Z J Public Health 1998; 22: 9-10. Communicable Diseases Surveillance. Pertussis epidemic continues. Commun Dis Intell 1997; 21: 359-360. Communicable Diseases Surveillance. Measles. Commun Dis Intell 1995; 19: 562-563. Andrews RM, Kempe AE, Sinn KK, Herceg A. Vaccinating children with a history of serious reactions after vaccination or of egg allergy. Med J Aust 1998; 168:491-494. Miller E. Collapse reactions after whole cell pertussis vaccination. Pertussis remains a bigger risk than collapse after vaccination [editorial]. BMJ 1998; 316: 876-877. Vermeer-de Bondt PE, Labadie J, RŸmke HC. Rate of recurrent collapse after vaccination with whole cell pertussis vaccine: follow up study. BMJ 1998; 316: 902-903. Peter G, editor. Pertussis. In: 1997 Red Book: Report of the Committee on Infectious Diseases. 24th ed. Elk Grove Village, Ill: American Academy of Pediatrics, 1997: 401. Cherry JD. Comparative efficacy of acellular pertussis vaccines: an analysis of recent trials. Pediatr Infect Dis J 1997; 16 (4 suppl): S90-S96. Committee on Infectious Diseases. American Academy of Pediatrics. Acellular pertussis vaccine: recommendation for its use as the initial series in infants and children. Pediatrics 1997; 99: 282-288. Communicable Diseases Surveillance. Surveillance of serious adverse events following vaccination. Commun Dis Intell 1995; 19: 273-274. Farrington P, Pugh S, Colville A, et al. A new method for active surveillance of adverse events from diphtheria/tetanus/pertussis and measles/mumps/rubella vaccines. Lancet 1995; 345: 567-569. Chen RT, Glasser JW, Rhodes PH, et al. Vaccine Safety Datalink Project: a new tool for improving vaccine safety monitoring in the United States. Pediatrics 1997; 99: 765-773.