An expert answers: Why smallpox vaccine is being prescribed for those with monkeypox

Dr Manisha Arora, Director – Internal Medicine at the CK Birla Hospital, Delhi, explained that monkeypox and smallpox, though related, are caused by different viruses and present distinct clinical features. Monkeypox is caused by the monkeypox virus, while smallpox was caused by the variola virus. Although both belong to the Orthopoxvirus genus, monkeypox is generally milder than smallpox.

One of the key differences between the two diseases is the presence of lymphadenopathy, or swollen lymph nodes, in monkeypox, which does not occur in smallpox. Monkeypox also has a lower mortality rate compared to smallpox, which was highly lethal before its global eradication in 1980. Smallpox causes high fever, and severe rash, and often leads to death, while monkeypox, although serious, typically has a more favourable outcome.

Why the smallpox vaccine is used for monkeypox

There is no specific vaccine developed for monkeypox. However, due to the close relationship between the monkeypox virus and the variola virus (which causes smallpox), Dr Arora explained the smallpox vaccine has been found to offer some protection against monkeypox.

What are some preventive measures for high-risk individuals? (file)

This cross-protection occurs because both viruses are from the same virus family. The smallpox vaccine, made from the cowpox virus, is especially useful in high-risk populations for preventing monkeypox, though it is not routinely recommended for the general public.

Protection measures against monkeypox

Protection against both monkeypox and smallpox involves standard viral infection prevention measures, said Dr Arora:

Good Hygiene: Frequent hand washing and maintaining personal hygiene can prevent the spread of these viruses.

Avoid Close Contact: Staying away from infected individuals and avoiding contact with animals that might carry the virus (such as rodents or primates) can reduce the risk of transmission.

Vaccination: While smallpox has been eradicated, and routine vaccination is no longer practiced, the smallpox vaccine can be used in specific cases to prevent monkeypox, especially in high-risk areas or populations.

These preventive strategies are crucial, especially in areas where monkeypox is prevalent or during outbreaks. Although smallpox is no longer a threat, understanding how to prevent monkeypox is vital for controlling its spread.