US CDC UPDATE: Those at high-risk of mpox need two doses Bavarian Nordic vaccination.

Adds background, study details and CDC quotation paragraphs 3-7

By Leroy Leo

May 18 (Reuters). The U.S. Centers for Disease Control and Prevention urges people who are at high risk for mpox, to get two doses Bavarian Nordic Jynneos. They cite new evidence that a U.S.-based study shows the regimen prevents infection better than a single shot.

The study, which appeared on Thursday, provided some of first evidence regarding the efficacy and safety of Jynneos, a vaccine that was deployed in last year’s global outbreak of mpox which affected more than 35,000 people in the United States.

The study on the real-world use of the vaccine, which was conducted between August 19, 2022 and Mar 31, 2023, among 917 individuals, revealed that it was 85.9% efficient in preventing diseases after two doses compared to 75.2% effective after one dose.

The study found that the vaccine was 70.2% efficient after two doses and only 51% effective with a single shot for those who were immunocompromised. Neither figure, however, was statistically meaningful, according to CDC’s Morbidity and Mortality Weekly Report.

The outbreak began in May of 2022 and disproportionately affected men who are gay, bisexual and have had sex with other men, as well as transgender individuals.

The recommendations come after a warning issued to U.S. doctors on Monday regarding the possibility of an increase in cases during this spring and summer, as people attend gay pride festivals and similar events.

Christopher Braden, CDC’s mpox response manager, said in a press briefing that without renewed efforts to prevent, particularly vaccination, there is a risk for a resurgence.

(Reporting and editing by Julie Steenhuysen, Bill Berkrot and Leroy Leo from Bengaluru)