Background: The world is on the verge of eradicating polio. In the absence of immunity, laboratory staff handling infectious clinical specimens or viable polioviruses may eventually become a source for transmission. Polio vaccine is mandatory in Bulgaria. Control of acquired immunity is carried out only sporadically. As antibody titers decline with age, determining the seroprevalence in adult laboratory staff would be a contribution to the risk assessment in case of polio importation.
Methods: Cell culture microneutralization assay for detecting antibodies against poliovirus 1 and 3 was applied.
Results: The seroprevalence of poliovirus 1 and 3 antibodies among personnel employed at the National Center of Infectious and Parasitic Diseases in Bulgaria, who are handling stool specimens, was 100 and 79%, respectively.
Conclusions: Seroprevalence meets the target of 80%. It can be concluded that personnel are protected against polioviruses and would not be a source of infection in case of polio importation.