Overview
Variola virus (the virus that causes smallpox) only causes disease in humans. Other related viruses, such as monkeypox, can infect both animals and humans. This unique characteristic of variola virus makes it an important virus to study and help us learn more about infectious diseases.
The goal of smallpox research is to address three areas critical to public health:
- Finding better antiviral drugs to treat smallpox.
- Making safer vaccines.
- Improvement of tests to detect variola virus.
About the research
Research to find a new treatment
Smallpox is caused by a virus. Medicines that fight diseases caused by viruses are called antiviral medicines. Some antivirals that can help treat smallpox or prevent it from getting worse include tecovirimat, cidofovir and brincidofovir. However, these drugs have not been tested in people sick with smallpox, so it is not known whether a person with smallpox will benefit from treatment with any of them.
There are two antiviral drugs, tecovirimat (TPOXX) and brincidofovir (TEMBEXA)approved by the US Food and Drug Administration (FDA) for the treatment of smallpox. Tecovirimat and brincidofovir were approved under the FDA’s animal rule, which allows efficacy results from adequate and well-controlled animal studies to support an FDA approval when it is not feasible or ethical to conduct efficacy studies in humans.
CDC is working with partners to find new and existing drugs that can reduce the harmful effects of variola virus. Researchers first look at each drug’s ability to stop infection in a laboratory. Then they figure out how the drug prevents infection from happening. What they learn can help us understand how to prevent variola viruses from spreading and to design better drugs to treat these viruses.
Research to make safer vaccines
The CDC also works with vaccine manufacturers to make new, safer vaccines and determine how well they work. Since these safer vaccines have never been used in an area with widespread smallpox, researchers cannot directly study their ability to prevent smallpox. Instead, researchers measure the effectiveness of new smallpox vaccines using indirect methods. They conduct clinical trials where volunteers agree to be vaccinated with the new vaccines and give blood samples. Researchers then take the blood samples, remove the serum (the clear part of the blood that contains substances called antibodies that fight disease), and test the serum’s ability to inactivate the variola virus in the laboratory.
Researchers also plan to study the new vaccines and drugs in mice and other animals. What they learn may give us a better idea of how well these vaccines might work in humans.
Research to make better tests
The CDC is also conducting research to develop better laboratory tests to more accurately detect smallpox-like viruses because this would help diagnose smallpox in patients. If a smallpox emergency occurred, public health authorities would need these tests to quickly confirm a diagnosis of smallpox.
