Testing methods for monkeypox and smallpox

Researchers at the Vaccine and Gene Therapy Institute (VGTI) at Oregon Health & Science University have developed new diagnostic methods to better detect future monkeypox or smallpox outbreaks. The research also sheds new light on the 2003 monkeypox outbreak in the US - monkeypox is closely related to smallpox. This new information suggests that the 2003 outbreak was larger than the 72 cases reported by the Centers for Disease Control and Prevention (CDC).

The test the CDC uses to confirm monkeypox cases requires that the virus be directly identified in blood or tissue samples. Because monkeypox virus is eventually cleared by the body, the evidence is quickly wiped out, resulting in a high percentage of unconfirmed cases due to the limited window of opportunity for diagnosis. In comparison, OHSU's research team tested samples using a variety of methods. One such test, called the ELISA test, resulted in very accurate results (95% sensitivity, 90% specificity.) This high level of accuracy allowed the scientists to correctly diagnose previously confirmed cases as well as confirm several probable, suspect cases of monkeypox that had remained unconfirmed for the last two years. Most importantly, the laboratory identified and confirmed three new cases of monkeypox that had previously gone undetected by the CDC.

The ELISA test is based on a Slifka laboratory research finding that specific genes found in the monkeypox virus are recognised by antibodies produced by the human immune system. By testing for this unique immune response, which remains detectable for years, researchers can accurately determine if the patient has been infected with the virus.