[Antitetanus vaccination: preliminary results of a study in Africa]

Two commercialized anatoxins, titrating 30 Lf per dose and adsorbed on Ca phosphate and Al hydroxide respectively, were studied in comparison with an experimental anatoxin titrating 25 Lf per dose and adsorbed on Al phosphate, and with a placebo. 595 schoolchildren from Cameroun were randomly assigned to four groups and inoculated twice, with a year's interval between the two inoculations. Serological checks were carried out by double-blind trials using the passive hemagglutination (HA) method on days 7, 90, 365 and 395. HA titers rose substantially after three months and then fell during the 12th month. The HA method does not give a clear indication of the amount of protection obtained after only one inoculation, but this amount would seem to be small according to the results of neutralization tests carried out on samples. It is only after the second injection that protection is provided for most subjects. Results vary depending on the anatoxin and are not linked to the--benign--clinical reactions observed. This study confirms that if anatoxins with high antigenicity are to be used, two injections are necessary and sufficient to guarantee good immunity protection.