A comparative study of agglutinin response after pertussis vaccination with the sauer vaccine and with a toxin vaccine and in untreated clinical pertussis

Summary Agglutination studies were made on several different groups of children who were given injections of pertussis vaccines, in untreated clinical pertussis and in nonpertussis respiratory infections. The object of these studies was to determine the following points: 1. The optimum dosage for vaccination. 2. The comparative antigenicity of vaccines that are made of freshly isolated and of stock pertussis bacilli. 3. The comparative value of the intramuscular and the intracutaneous methods of administering the vaccine when given after short or long intervals. 4. The agglutinin response after vaccination and during infection and early convalescence. The results obtained were as follows: a. The average agglutinin response in the vaccinated children was, on the whole, proportional to the dosage given. In those in whom the maximum dose did not exceed 8.5 billion bacteria given intracutaneously or 39 billion bacteria given intramuscularly, only a few of the children showed an increase in agglutinins; although the titer of some of those that did show an increase was fairly high. On the other hand, a dose of 80 billion bacteria stimulated agglutinins in a large percentage of the children (55 per cent in the group that received Sauer's vaccine and 84 per cent in the group that received our toxin vaccine). b. The intracutaneous method compared favorably with the intramuscular method in stimulating agglutinins although the dose used intracutaneously was very much smaller than the intramuscular dose. c. The agglutinin response was better in the groups that were given the injections at two-day than at seven-day intervals. However, the groups studied were very small, and therefore definite conclusions cannot be drawn at present. d. The agglutinin response was better in the group of children who were injected with a vaccine that was made of stock cultures that were grown on sheep blood infusion agar (toxin vaccine) than in those who were injected with a vaccine that was made of freshly isolated cultures that were grown on human blood-Bordet-Gengou medium (Sauer). e. The agglutinin response in pertussis cases differed markedly from that of the vaccinated children, in the length of time at which the maximum was attained and in the height of its curve (Chart 3). But having attained the maximum (the maximum titer differed widely in different cases) it dropped rapidly. It corresponded closely in this respect with the drop in the agglutinin titer of the vaccinated children. It seems therefore that there was a decrease in agglutinins almost as soon as infection ceased and convalescence began. This again corresponds with the decrease in agglutinins in the vaccinated children soon after the active stimulation of the vaccine was discontinued. f. The agglutinin content of the serums of all but 2 of 12 children who had nonpertussis respiratory infections was in the normal range. These 2 children were definitely exposed to pertussis and may have had a mild infection which would account for their high agglutinin titers.