How Smallpox Is Treated

Show Article Table of Contents

When smallpox was still a naturally occurring medical disease, treatment was often supportive. Patients were made as comfortable as possible and the disease was left to take its course. There were no useful antiviral medication options. Post-exposure vaccination was the only viable treatment option that doctors could try, and it relied upon the patient recognizing that he or she was exposed (or that healthcare officials tracked down those who had any contact with newly diagnosed patients).

Since the World Health Organization (WHO) announced that smallpox was eradicated in 1980, researchers have only had animal analogs to test treatment options. Development of antiviral medications to treat variola is now based solely on the zoonotic versions of orthopoxvirus.

Post-Exposure Vaccination

Giving a patient the smallpox vaccine after the patient has already been exposed was the main treatment of choice if it was thought that there would be time for the vaccine to work. The treatment was not an option if the patient already had developing lesions. However, there had been a decrease in severity of smallpox and in some cases, it was likely that smallpox never developed as a result of post-exposure vaccination.

Unfortunately, the data obtained during the years when healthcare officials were actively eradicating the disease are not necessarily accurate to a modern outbreak. Contemporary patients in many parts of the world are immunocompromised due to HIV and aggressive modern medical treatments. The vaccine used during the eradication years was the first generation and today's version might be more or less effective. Likewise, side effects of the vaccine might be different and will certainly have different frequencies of common effects.

Antiviral Medications

Because there have been no more cases of actual smallpox occurring in humans since 1977, there's no way to test new antiviral medications on a human infected with the variola virus. Instead, researchers use humans infected with other orthopoxviruses or on primates infected with live variola virus. There are two potential new antiviral drugs being developed and one is already being stockpiled in the event of a smallpox outbreak.

Without human testing with actual variola virus, there is no way to know for sure how these medications will behave or if they will be effective. Animal testing shows that administration of an antiviral medication after lesions appear—that's the expected clinical sign that tells doctors that a patient has smallpox—does shorten the illness in a statistically significant way. However, antiviral medications are not a panacea and even if the drugs are effective for smallpox in humans, dosing might be way off in the initial cases.


Since treatment for smallpox is limited to only vaccination and a couple of untested antiviral medications, prevention becomes the best treatment option. The current stockpiles of live variola virus are kept only in two labs worldwide: the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, and the VECTOR Institute in Russia. These live virus specimens are kept for research purposes in order to help identify potential drugs and other treatment options.

The two biggest threats to create a smallpox outbreak are either release of the live variola virus (accidentally or intentionally) or a mutation of another orthopoxvirus, most likely the monkeypox virus, to affect humans in a similar way as the smallpox disease.

View Article Sources