DURATION OF HUMORAL POSTVACCINATION AND P OSTINFECTION IMMUNITY TO VENEZUELAN EQUINE ENCEPHALOMYELITIS VIRUS

Serological studies on the levels of virus-neutralizing antibodies (VN A) against Venezuelan equine encephalomyelitis virus (VEE) were carrie d out by the standard method in 280 human subjects given a single prim ary inoculation of experimental forms of live vaccines against VEE pre pared from attenuated strains No. 15 and No.230. The VNA were found to persist, in the blood of the vaccinees for 5-25 years (the observatio n period) from the time of vaccination practically at the same level. The VNA titres did not depend on the form of the preparation (for subc utaneous or oral administration) used for immunization. Similar studie s were carried out on sera from 17 convalescents after VEE experienced in the past. An identical result was obtained. It is suggested that i mmunity to VEE persists for life.