In 1988, the World Health Assembly endorsed the goal of eradicating poliomyelitis worldwide. At the time, the estimated annual number of new cases of paralysis was 350,000, and poliomyelitis was considered to be endemic in 125 countries.1 In the 25 years since then, the incidence of poliomyelitis has been reduced by more than 99%, and only three countries — Pakistan, Nigeria, and Afghanistan — ...

Endemic wild polioviruses have been eliminated from most of the world, and the number of human paralytic cases has been reduced by .99%, from an estimated annual incidence of .500,000 cases to ,2000 cases [1–3]. Circulating wild polioviruses remain endemic in only 2 major locations, Nigeria and a zone extending from northern India west to Pakistan and Afghanistan [1–3]. Furthermore, wild-type 2...

In this study we lyophilized three types of live attenuated polioviruses (Sabin vaccine strains) and evaluated the lyophilized vaccine viruses' heat stability. The virus titers were measured after heating at 37 and 45 and then compared with the titers of conventional liquid vaccine viruses similarly treated. The results showed that lyophilization, while slightly reducing vaccine virus titers,...