Control of an outbreak of group C meningococcal meningitis with a polysaccharide vaccine.

An outbreak of meningitis in Royal Air Force recruits due to Neisseria meningitidis Group C type PI, 2 gave the first opportunity for polysaccharide vaccine to be used for controlling such an outbreak in the U.K. The effect of the vaccine on an epidemic in a large recruit training centre was studied after chemoprophylaxis had failed. With the possible exception of one vaccinee, further cases did not arise among camp personnel. Vaccination was continued until the carriage rate of the epidemic strain among recruits leaving the camp had fallen from greater than 19 to less than 1%. Two persons who had only indirect contact with the camp developed the disease. Vaccination early in the course of such an outbreak appears to be a useful and practical method of limiting symptomatic infection but not acquisition of the epidemic strain.

Immunity to diphtheria in young British adults.

Of 906 recruits aged between 16 and 20 years who were Schick-tested upon entry to the Royal Air Force, 775 were tested for circulating Corynebacterium diphtheriae antitioxin by means of an indirect haemagglutination (IHA) method. Of the total population, 95.7% were Schick-test negative, 3.5% were Schick-test positive and 0.8% gave pseudo-reactions. Of those tested by the IHA test, 37.7% were regarded as immune, 47.0% as 'immune-susceptible' and 15.3% as non-immune. Discrepancies between the two tests were discovered. Of those persons found to be Schick-test positive, 34.6% possessed circulating antitoxin; of those Schick-test negative, 13.5% were regarded as non-immune. A history of diphtheria immunisation in childhood was found to be a poor predictor of immunity. A protocol for selective diphtheria immunisation of adults is proposed.