Variola virus belongs to the genus of orthopoxvirus, and there are some other infectious members, such as Vaccinia virus, cowpoxvirus, and monkeypox virus.
在正痘病毒属还有另外几种病毒对人具有一定的感染性，如痘苗病毒、牛痘病毒和猴痘病毒。
2
The vaccinated person developed antibodies which protected both against the cowpox infection and against the closely related virus that caused smallpox.