MOSCOW, May 23. /TASS/. Mass vaccination against smallpox staged in Russia earlier helped to develop herd immunity enough to prevent the spread of monkeypox, Russia’s sanitary watchdog said on Monday.

"Earlier vaccination against smallpox reduces the risks of severe monkeypox cases, since all poxviruses give good cross protection. Thanks to the mass vaccination against smallpox conducted in Russia before, we have herd immunity to curb the spread of monkeupox," it said.

Russian Health Minister Mikhail Murashko said earlier that obligatory vaccination against smallpox had been conducted in the country until 1980. According to Natalia Pshenichnaya, deputy director of the Central Research Institute of Epidemiology, there is no specific vaccine against monkeypox, but a smallpox vaccine can ensure safe protect against this disease.

Monkeypox is a viral zoonotic disease transmitted to humans through close contact with an infected person or animal (rodents, primate) or with material contaminated with the virus. It symptoms include fever, headache, muscle pains, swollen lymph nodes, feeling tired, and rash. The incubation period is around ten days and the symptoms typically last from two to four weeks. According to the World Health Organization (WHO), the case fatality ratio ranges from one to ten percent, with the majority of deaths occurring in younger age groups.