LONDON, SATURDAY 3 DECEMBER
MEDICAL JOURNAL Influenza vaccination Early in recent winters the DHSS has made recommendations for the use of influenza vaccines in a letter from the Chief Medical Officer to practising doctors. The advice this year (CMO(77)22) shows little change from usual. An injection of killed vaccine should be considered for those with any condition predisposing to serious effects in the event of an attack-for example, chronic pulmonary or heart disease, renal disorders, or diabetes. Vaccination could also be offered with advantage to anyone at special risk of infection, such as nurses and ambulance men, and also to children at boarding schools, where outbreaks may be severe. Nevertheless, the new recommendations show some points of difference from previous years. Vaccination for elderly people resident in institutions and geriatric wards has been given increased emphasis. This policy has its critics: pneumonia has been regarded as the old man's friend, and that must presumably include influenzal pneumonia. Nevertheless, outbreaks of influenza in groups of residents in homes for the elderly are often unusually severe and carry a high death rate -and it is not just the ill and frail who are killed. Even so, the DHSS recommendation does not go as far as the policy in the United States, which advocates vaccination for all people over 65 years of age.' Mortality from influenza is usually most evident among the elderly, and in England and Wales a recent estimate2 based on calculations of excess mortality suggested that in each winter between 1967 and 1973 an average of about 11 000 elderly people died directly or indirectly from the effects of influenza. The American policy is intended to minimise or even eliminate this effect of epidemics, but so far it has not measurably affected excess mortality rates, partly because it is very difficult to reach many of the elderly popula-
tion.3 The CMO's letter also refers to Guillain-Barre syndrome, many cases of which were associated with the "swine" influenza vaccine campaign in the United States last winter.4 There the risk of this complication was estimated to be about 1 in every 130 000 vaccinations-a rate which is probably lower than the risk of death from influenza among unimmunised people under 65 years of age during an average winter outbreak in Britain. We do not know whether this hazard is specifically associated with swine vaccine rather than any influenza vaccine, or, indeed, whether the association is with influenza vaccine rather than any injected vaccine. Possibly the Guillain-Barre syndrome is simply a rare complication that became obvious only by the unprecedented scale of © BRITISH MEDICAL JOURNAL 1977.
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the campaign-over 40 million injections were administered -and the thorough epidemiological observations that accompanied it. The DHSS advice implies that in Britain a risk of Guillain-Barre syndrome should not be seen as a contraindication to influenza vaccination; and undoubtedly this attitude is appropriate for patients in one of the high risk groups, for whom the benefits of vaccination outweigh a remote hazard associated with a vaccine which in general has proved to be extremely safe. At the same time, the orthodox British view remains conservative: killed influenza vaccine is not recommended for controlling the general spread of influenza, and a remote risk of Guillain-Barre syndrome lends some support to this view, at least for interpandemic outbreaks. The vaccines manufactured for use this winter are prepared from the A Victoria 3 75 and B Hong Kong'8 73 viruses and are expected to provide protection against the strains likely to be prevalent. Some of last year's vaccine may still be available, prepared from the same strains together with the swine influenza virus, A New Jersey 76. The danger of a swine influenza pandemic is thought to have disappeared, at least for the present, but it could reappear in the future. Hence, while a vaccine containing the swine component is not strictly necessary this winter, it may provide a basal immunity against a future outbreak. An alternative to the conventional vaccines has become available with the new surface-antigen vaccines.36 The essential immunising components of killed vaccines are the haemagglutinin and neuraminidase antigens on the surface of the virus, and methods have been developed by which these may be split from the virus particle and purified. To render these sufficiently antigenic an adjuvant such as aluminium hydroxide is usually incorporated. The available evidence shows that these new vaccines may be effective immunising agents, at least when prepared from interpandemic viruses, and that they are less inclined to produce side effects such as fever and sore arms. In general, the fewer unnecessary proteins and other materials in a vaccine the better, and the introduction of these purified vaccines seems a useful development. Center for Disease Control, Morbidity and Mortality Weekly Report, 1977, 26, 193. 2 Clifford, R E, et al, Internationalyournal of Epidemiology, 1977, 6, 115. 3Ennis, F A, et al, Influenza: Virus, Vaccines and Strategy, ed P Selby. New York, Academic Press, 1976. 4British MedicalJournal, 1977, 1, 1373. 5 British Medical3Journal, 1972, 3, 658. 6 Potter, C W, et al, Journal of Hygiene, 1975, 75, 353.
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