Further studies on autoclaved cercarial vaccine against schistosomiasis: safety, longevity and stability.

The autoclaved cercarial vaccine (ACV) which is a special type of killed vaccine has been reported to induce experimental high level of homologous protective immunity. This study was to adjust the dose and to assess vaccine safety, longevity and stability as well as the possibility of transplacental transmission of immune response from pregnant mice to their offspring. The results showed that two doses of the lowest most effective concentration of ACV that achieved the high percentage reduction of worm burden is safe as demonstrated by absence of any local or systemic side effects, normal blood picture and normal liver and kidney function tests. ACV is stable when kept either at 4 degrees C for six months or at -35 degrees C for up to 12 months and it offered considerable duration of longevity. Offspring of vaccinated mothers didn't show any signs of protection against challenge infection.