FRIDAY, May 19, 2023 (HealthDay News) -- The JYNNEOS vaccine seems to be effective for preventing mpox disease, with better protection conferred from a two-dose series, according to a study published online May 18 in the New England Journal of Medicine.

Nicholas P. Deputy, Ph.D., from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues conducted a case-control study to examine the effectiveness of JYNNEOS vaccination in preventing medically attended mpox disease among adults. Data were included for 2,193 case patients with an mpox diagnosis code or positive orthopoxvirus or mpox virus laboratory result and 8,319 control patients with an incident diagnosis of HIV infection or a new or refill order for preexposure prophylaxis against HIV infection.

The researchers found that 25 case patients and 335 controls received two doses (full vaccination), which had an estimated adjusted vaccine effectiveness of 66.0 percent. In addition, 146 case patients and 1,000 controls received partial vaccination (one dose), which had an estimated adjusted vaccine effectiveness of 35.8 percent.

"JYNNEOS vaccine was effective at reducing the risk of mpox disease, with effectiveness that appeared to be greater among persons who completed the two-dose series," the authors write. "In addition to vaccination, persons might benefit from strategies to prevent or reduce the risk of acquiring or transmitting mpox."