"Hayflick also supplied WI-38 liberally to aspiring vaccine-makers. One was Stanley Plotkin, a Wistar scientist and a physician who had seen at first hand the effects of the huge rubella epidemic that swept the United Kingdom and the United States in the early 1960s. Rubella can be devastating to fetuses whose mothers are infected: those that are not killed in utero are frequently born blind, deaf, mentally disabled or with some combination of these conditions. Working at the Wistar, Plotkin grew rubella in WI-38 at 30 °C, cooler than body temperature, creating a weakened strain that still fired up the immune system enough to protect against future infections. Trials showed that his vaccine induced better immunity against rubella than competitors. Plotkin’s vaccine was licensed in Europe in 1970 and in the United States in 1979. A version made by the pharmaceutical company Merck, based in New Jersey, is today the only rubella vaccine available in the United States, and GlaxoSmithKline uses Plotkin’s weakened virus in a rubella vaccine that it markets in Europe and Australia. The rubella vaccine was only one of many made using WI-38. In the 1960s, a WI-38-based measles vaccine was licensed in the former Soviet Union and Koprowski developed a rabies vaccine using the cells. In the early 1970s, the pharmaceutical company Wyeth (now part of Pfizer) launched an oral adenovirus vaccine developed using WI-38 and Pfizer, based in New York, used WI-38 to make a vaccine against polio. Today, the cells are also used by Merck to make vaccines against chickenpox and the painful nerve infection shingles."