In the 1970s, Japanese scientist Takahashi and his colleagues isolated a virus from a specimen of a boy suffering from natural chickenpox. After several times of attenuated culture, the obtained virus was named Oka strain and became the standard virus strain for varicella vaccine production in the world. Oka strain varicella vaccine has been used worldwide for more than 30 years, and its safety and effectiveness have been widely confirmed. I. Both domestic and imported varicella vaccines are Oka strains The domestic varicella vaccine was first produced by Shanghai Institute of Biological Products imported technology from Japan. In 2000, there were also imported varicella vaccines from SmithKline Company. After that, many vaccine enterprises in our country began to produce and Read More …