During the recent smallpox epidemic at Tabriz, 123 cases of smallpox and 17 deaths occurred. About 92 per cent of the population was vaccinated within three weeks, abruptly terminating the epidemic. Interesting features of the epidemic included: an instance of transmission by fomites; the occurrence of a second attack of smallpox in one individual; and a marked preponderance of female cases, attributed to less vaccination of females in this cultural area. The susceptibility to vaccinia of persons over 35 and the absence of smallpox in this group indicated that following vaccination immunity to smallpox may persist longer than immunity to vaccinia. Failures of vaccination in the past were attributed to the use of glycerolated vaccine without adequate refrigeration facilities. The use of lyophilized vaccine was proposed.
Present address, U.S. Operations Mission, American Embassy, LaPaz, Bolivia.