Collapse reactions after whole cell pertussis vaccination: pertussis remains a bigger risk than collapse after vaccination

British Medical Journal, March 21, 1998 by Elizabeth Miller

"No child should be denied immunisation without serious thought as to the consequences both for the individual and the community." This powerful statement prefaces the chapter on contraindications in the new edition of the United Kingdom's Handbook on Immunisation against Infectious Disease.[1] In the 1970s a barricade of contraindications to pertussis vaccine was erected in response to undue concerns about safety. As the evidence has been reassessed, this barricade has now been largely demolished.

In 1981, without scientific substantiation, pertussis vaccine was contraindicated for a wide range of conditions, including cerebral irritation in the neonatal period and a family history of epilepsy or other diseases of the central nervous system.[2] Interpretation of these recommendations was left to the vaccinating doctor or health visitor, resulting in considerable variation in practice and a large fall in pertussis immunisation rates.[2] In contrast, the latest guidelines now recommend pertussis vaccine for children with a personal history of epilepsy and for those who have had a convulsion after a previous dose. The guidelines also give a comprehensive list of conditions that are not contraindications to vaccination.[1]

Collapse after pertussis vaccine, the so called hypotonic-hyporesponsive episode, remains a contraindication to further doses as so far there has been no information on the outcome when such children are revaccinated. The pathogenesis of this condition, which typically occurs after a first dose and has a benign outcome,3 is still unclear and estimates of its incidence differ widely. In a recent efficacy trial in Sweden, the risk after a first dose of a British whole cell diphtheria, tetanus, and pertussis vaccine was around 1 per 1000 doses,[4] although a prospective study in England found only one possible case after 6000 first doses of a similar vaccine.) Whatever the cause and incidence, without information on the risk of revaccination doctors have been understandably reluctant to give further doses of pertussis vaccine to children experiencing such an episode. The paper in this week's issue by Vermeer-de Bondt et al provides this (p 902).[6]

They describe 101 children who experienced a hypotonic-hyporesponsive episode, of whom 84 subsequently received further doses of pertussis vaccine: none experienced a recurrence or other adverse event. In contrast, one of the 17 children who remained unvaccinated had severe pertussis. In an earlier study in America, one of 14 children denied further vaccine because of a hyptonic-hyporesponsive episode or convulsion after a previous dose later developed pertussis, which lasted for three months and was transmitted to both her parents.[3] Interestingly, one case of encephalitis (190 days after vaccination and therefore unrelated) occurred among the 82 892 children who received pertussis vaccine in the Swedish trial; three cases occurred among the 17 607 children who did not participate--all three resulted from a confirmed pertussis infection. Such observations highlight the real risks and benefits of vaccination.

How can the findings of the Dutch workers be translated into policy and practice? Their paper should be considered by the UK Joint Committee on Vaccination and Immunisation and similar advisory bodies in other countries and its message translated into a clear policy statement Those giving the vaccine need to be reassured that their actions accord with national policy based on expert independent review of evidence, particularly when the manufacturers' date sheets may list a variety of contraindications drawn up with a view to protecting the vaccine rather than the child.[2] With the current media interest in Britain on the alleged risks of measles, mumps, and rubella vaccine, the Dutch paper is a timely reminder that a sound, evidence based assessment of the risks of withholding, as well as giving, a vaccine is the basis on which national policy should be made.

[1] Department of Health, Welsh Office, Scottish Office Department of Health, Department of Health and Social Services (Northern Ireland). Immunisation against infectious disease London: HMSO, 1996.

[2] Hull D. Interpretation of the contraindications to whooping cough vaccination. BMJ 1981;283:1231-3.

[3] Baraff LJ, Shields WD, Beckwith L Strome G, Marcy SM, Cherry JD, et al. Infants and children with convulsions and hypotonic-hyporesponsive episodes following diphtheria-tetanus-pertussis immunisation: follow-up evaluation. Pediatric 1988;81:789-94.

[4] Olin P, Gustafsson L, Rasmussen F, Hallander H, Heijbel H, Gottfarb P. Efficacy trial of acellular pertussis vaccines. Technical report trial II with preplanned analysis of efficacy, immunogenicity and safety Stockholm: Swedish Institute for Infectious Disease Control, 1997: 1-65.

[5] Pollock TM, Miller E, Mortimer JY, Smith G. Symptoms after primary immunisation with DTP and DT vaccine. Lancet 1984;ii:146-9.

[6] Vermeer-de Bondt PE, Labadie J, Rumke HC. Rate of recurrent collapse after vaccination with whole cell pertussis vaccine: follow up study BMJ 1998; 316:902-3.