News Release

Assessing Early Data on Monkeypox Vaccine’s Effectiveness


Last week, Rochelle Walensky, the director of the CDC, reported that early analysis indicates that people who were eligible for the Jynneos vaccine but did not receive it were 14 times more likely to contract the virus compared with vaccinated people. This is the first major outbreak in which the U.S. is using Jynneos, and this early analysis is some of the first data on the vaccine’s real-world effectiveness. But Keletso Makofane, a specialist in intersections of health and human rights concerns, spoke with the Institute for Public Accuracy about possible measurement errors in the data. 

    Makofane is a health and human rights fellow at the FXB Center for Health and Human Rights at Harvard University. He is also a principal pnvestigator on the RESPND-MI research project, which is a community-led survey of monkeypox symptoms and networks among queer and trans people in New York City.

Makofane said it is important for the public not to “over-interpret the data… the statistic is likely an overestimation of [the vaccine’s] effectiveness.”

    “My main concern,” Makofane said, is that “the way [researchers] determined which cases had been vaccinated and which had not was to link case data to vaccine registry data. If a person with confirmed MPX was not found in the registry, they would have been classified as unvaccinated. That’s a problem in states that did not collect linkage data… and would have the impact of misclassifying vaccinated cases as unvaccinated cases, increasing the measured risk among the unvaccinated while artificially decreasing it in the vaccinated.”

Last week, the nearly $27 billion requested by the White House to respond to Covid-19 and monkeypox virus outbreaks was dropped from the continuing resolution in Congress. Advocates from 50 groups wrote to appropriations committee heads, urging them to authorize the request. The letter includes data about the disproportionate impact of monkeypox on marginalized communities worldwide. In the U.S., Black and Latino men represent more than two-thirds of cases, but less than one-third of the recipients of the first administered Jynneos vaccine doses