Risk of serious infection following splenectomy.

MBRIIHUNA A similar reduction in incidence was shown among those children who were known to be in contact with measles in their own homes and presumably exposed to heavy infection. The attack rates in a representative sample of children exposed at home were 9% in the killed/live-vaccine group, 6%, in the live-vaccine group, and 83 % in the unvaccinated group. Those children who defaulted from vaccination and those who were ineligible were also followed up in the same way as the children who took part in the trial. It was shown that the excluded children were in general as susceptible to measles as the unvaccinated control group, and it was thus most unlikely that their exclusion had materially affected the results of the analysis of the main trial. Although vaccination was highly effective it was unable to protect all children from measles. It is true that a few of the cases occurred soon after vaccination, perhaps before immunity had had time to develop, but most of them occurred later and were probably due to the inability of some children to produce an adequate antibody response. This view is supported by the results of the serological study in which a small proportion of children vaccinated by each method showed no antibody response. It is possible that a less attenuated live vaccine would produce protection in a greater proportion of children, but there is the probability that it would also produce more pronounced reactions and in consequence be less suitable for large-scale routine use. In considering which of the two procedures studied is the more suitable to use in vaccinating against measles, the following points should be taken into account. Both live vaccine alone and killed vaccine followed by live give a substantial and similar degree of protection in normal children aged 1 to 2 years, but it is not yet known how long the immunity will last. Killed vaccine given before live vaccine has the advantage of reducing the frequency of reactions including convulsions. On the other hand, vaccination with live vaccine alone requires only one injection. But no matter which procedure is chosen it is clear from the results of this trial that vaccination, if done on a large scale, could produce a substantial reduction in the incidence of measles in this country. Such a reduction would undoubtedly lighten the burden placed on family doctors and parents, especially in an …