Who developed the first chickenpox vaccine used for routine immunization?

Michiaki Takahashi developed the first chickenpox vaccine used for routine immunization.

Takahashi, a Japanese virologist, developed the vaccine in the 1970s after isolating the Oka strain of varicella-zoster virus from a child with chickenpox. He weakened the virus through repeated growth in different cell cultures, producing a live attenuated vaccine.

Japan approved the vaccine in 1986, and other countries later adopted it. The vaccine prevents varicella, the infection commonly called chickenpox. It also helped establish a way to reduce the later burden of shingles, because shingles results from reactivation of the same virus after it remains dormant in nerve tissue.

A common mix-up is confusing chickenpox with smallpox. They are caused by different viruses and require different vaccines. The chickenpox vaccine is based on varicella-zoster virus, while smallpox vaccination targets variola virus.