Results of a case–control study of electronic health record (EHR) data show that U.S. patients with mpox (formerly monkeypox) were less likely to have received 1 or 2 doses of JYNNEOS vaccine than control patients. “The findings suggest that JYNNEOS vaccine was effective in preventing mpox disease, and a two-dose series appeared to provide better protection,” the authors conclude.
Cosmos, a nationwide Epic EHR database, was used to identify case patients with an mpox diagnosis code or positive orthopoxvirus or mpox virus laboratory result and control patients with an incident diagnosis of HIV infection or a new or refill order for preexposure prophylaxis against HIV infection between Aug. 15, 2022, and Nov. 19, 2022. With vaccine effectiveness calculated as (1−odds ratio for vaccination in case patients vs. controls)×100, the results were as follows: “Among 2,193 case patients and 8,319 control patients, 25 case patients and 335 control patients received two doses (full vaccination), among whom the estimated adjusted vaccine effectiveness was 66.0% (95% confidence interval [CI], 47.4 to 78.1), and 146 case patients and 1,000 control patients received one dose (partial vaccination), among whom the estimated adjusted vaccine effectiveness was 35.8% (95% CI, 22.1 to 47.1).”