War Surgery and Medicine
Efficacy of TAB Vaccine
Efficacy of TAB Vaccine
The epidemic among the recently-arrived reinforcements in September 1943 led to questioning of the efficacy of the vaccine prepared in New Zealand. In one infantry depot there were 69 cases of typhoid, and an analysis of the 67 inoculation states available showed that 58 had received New Zealand vaccine only and that 6 of these states were faulty also, while 9 had received New Zealand and RAMC vaccine but 8 of these states were faulty in one way or another. Other troops fully protected with RAMC vaccine were exposed to the infection but did not develop typhoid, and it is possible that re-inoculation with RAMC vaccine brought the epidemic to a close.page 496
As the pathologist of 1 General Hospital pointed out, typhoid fever was of rare occurrence amongst Middle East troops properly inoculated with RAMC vaccine, and when an outbreak of typhoid fever did occur it affected almost exclusively those who had not been properly protected with RAMC vaccine. It was a common finding that the local and general reaction produced by the first dose of RAMC vaccine was often severe—surprisingly so if any great degree of immunity had been conferred by the previous inoculations in New Zealand. Subsequent doses of RAMC vaccine produced less severe reactions. It was found that a particular organismal type was common to the New Zealand cases in the epidemic and that British and RAF cases occurring at the same time were caused by different types of the organism. It seemed that the vaccine used in New Zealand did not give complete protection against organisms found in Egypt.
In the First World War the same question of the potency of vaccine given in New Zealand arose, and all the troops were re-inoculated with RAMC vaccine. The question was investigated by Major Bowerbank at 1 NZ General Hospital in Egypt in 1916. He held that the New Zealand vaccine had been effective and that nearly all the cases had been due to paratyphoid infection against which the original vaccine had not been prepared.
The use in 2 NZEF of RAMC vaccine made from local strains produced fairly complete immunity. It would appear from experience in the Middle East that vaccine should be made not from any local New Zealand strain, but from the proper strains of tested virulence and antigenic power obtained from the country of campaign. Experience also teaches that the meticulous carrying out of inoculation at specified intervals is important.