A new 23 valent pneumococcal vaccine: immunogenicity and reactogenicity in adults

A 23 valent pneumococcal vaccine containing 25 micrograms of each polysaccharide was administered to 30 healthy adults. Adverse reactions were always mild, consisting only of local pain and erythema in most subjects. Pre- and four weeks post-vaccination sera were analysed by radioimmunoassay. Geometric mean titre (GMT) ratios were between 2.3 and 14.3 (overall mean X 5.7) according to type. A level of 300 ng of antibody N/ml, the supposedly protective level, was achieved in at least 86.6% of the subjects for all the serotypes.