Influence of Vaccination with Formalin Inactivated Vaccine upon Gastrointestinal Infection with Polioviruses

Abstract

The influence of vaccination with killed poliomyelitis vaccine upon the susceptibility of the gastrointestinal tract to polio-viruses was investigated. Family contacts of known cases of polio-myelitis were studied. Children vaccinated with one or 2 doses were found to be excreting virus as frequently in their feces as were their unvaccinated peers. Only 8 children who had received 3 properly spaced injections of vaccine were available for study and poliovirus was isolated from 3. In order to determine whether or not vaccination had been effective in evoking neutralizing antibody, tests were run on the sera of many of the family contacts of poliomyelitis patients. Additional data of the same type were accumulated from persons in families in which there was no polivirus infection. Comparisons in regard to the presence or absence of antibody and the titer of antibody revealed little differences between the vaccinated and unvaccinated children. What differences were observed indicated that the type 2 component of the vaccine was a better antigen than types 1 and 3. Data are presented which suggest that neutralizing antibody in the blood has little influence upon the susceptibility of the lower intestinal tract of man to poliovirus infection. However, the age of the individual, unrelated to the presence of antibody, correlates well with the presence of virus in the feces. The younger the person, the more likely is he to be infected. Evidence is also presented, in confirmation of that of others, indicating that even in persons known to be infected with poliovirus, the virus is more frequently isolated from children than from adults. It is concluded that immunization with killed poliomyelitis vaccines cannot be expected to decrease the numbers of persons in the community with alimentary poliovirus infection. Thus, vaccination, while of value to the persons immunized, is unlikely to provide pro-tection to those not vaccinated.