SEQUENTIAL AND COMBINED USE OF INACTIVATED AND ORAL POLIOVIRUS VACCINES - DOLJ DISTRICT, ROMANIA, 1992-1994

To determine the feasibility of a vaccination strategy that would redu ce the risk of vaccine-associated paralysis while retaining a barrier against the spread of wild poliovirus, a 2-year project was undertaken using enhanced-potency inactivated poliovirus vaccine (IPV) administe red at 2 and 3 months of age followed by doses of both IPV and oral po liovirus Vaccine (OPV) administered at 4 and 9 months of age, Vaccinat ion coverage by 12 months of age with three or more doses of IPV and t wo doses of OPV among 16,566 infants eligible for vaccination was >95% and >80%, respectively. Among 51 children from whom blood samples wer e obtained 45 days after their third dose of IPV and first dose of OPV , 100% had serum neutralizing antibodies (reciprocal titer greater tha n or equal to 10) to all three poliovirus types. No cases of paralytic poliomyelitis due to either wild or vaccine-related strains were repo rted. The project demonstrated the feasibility, safety, and high immun ogenicity of sequential use of IPV followed by OPV in Romania.