Does the smallpox (vaccinia) vaccine work to prevent monkeypox?
Officials are claiming that the vaccine is 85 percent effective. That figure is based on one study done in the 1980s in Africa. That study evaluated 209 cases of monkeypox that occurred during a five-year period from 1980-1984 in the dense tropical rainforests of the Democratic Republic of Congo (at that time Zaire). These cases represented 125 separate episodes of disease occurrence. More than half of the cases did not spread to anyone else (only one case occurred in most episodes). The incidence of disease among vaccinated contacts of people with monkeypox was compared to the incidence in unvaccinated contacts. Both household contacts and people living in other residences were included. Over 1500 contacts of patients with the disease were identified. Only 12 cases of disease occurred in 1,099 vaccinated contacts (one percent) compared to 35 cases in 474 unvaccinated contacts (7.4 percent). The calculation (7.4-1.1 / 7.4) yields the 85 percent effectiveness conclusion. The assumption
