Public health officials tracking Ebola outbreaks have long faced a critical blind spot: existing blood tests cannot distinguish between antibodies from vaccination versus natural infection, undermining both surveillance efforts and vaccine coverage assessments. This diagnostic gap has complicated outbreak responses, particularly in regions where both vaccination campaigns and natural transmission occur simultaneously.
Researchers have developed a multiplex blood assay that solves this problem by targeting three specific protein markers. The test detects antibodies against two Ebola virus proteins—GP1,2 and secreted glycoprotein (sGP)—plus a modified vesicular stomatitis virus nucleoprotein that exists only in the ERVEBO vaccine, not in wild Ebola virus. Testing samples from US vaccinees and controls, plus comparison samples from the Democratic Republic of Congo, the assay achieved 100% sensitivity and over 97.6% specificity for identifying vaccinated individuals. Field validation in Guinea following a ring vaccination campaign confirmed vaccination status in 94.8% of people with written documentation and 90.8% with verbal confirmation.
This breakthrough addresses a fundamental challenge in Ebola preparedness and response. Previous serologic surveillance relied on tests that treated all antibody-positive individuals as potentially infected, creating false signals during vaccination campaigns. The new assay enables more precise epidemiological tracking by definitively identifying vaccine-induced immunity. This capability becomes increasingly valuable as ERVEBO deployment expands globally, particularly in outbreak-prone regions where distinguishing vaccination from infection directly impacts public health decision-making and resource allocation during emergency responses.