Breakthrough Study Reveals Efficacy of Smallpox Vaccine Against Mpox

In a groundbreaking development, recent research has revealed that a single dose of the Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) smallpox vaccine shows moderate efficacy in preventing mpox infections. This important discovery was published in The BMJ, as the World Health Organization (WHO) declared mpox a global public health emergency for the second time in three years in August 2024, underscoring the urgency for effective preventive measures.

Current Vaccination Landscape

Currently, there are two mpox vaccines approved for emergency use in Congo: LC16 (KM Biologics) and Jynneos (Bavarian Nordic). However, the distribution of these vaccines remains critically low—with only 15,000 doses of Jynneos available against an estimated need of 10 million doses to control the ongoing outbreak. As of August 2022, these vaccines are not accessible in pharmacies, highlighting a pressing need for increased resources and a comprehensive vaccination plan.

Study Design and Findings

The study involved nearly 10,000 men, aged 18 and older, who had previously been treated for a bacterial sexually transmitted infection (STI) or had received a prescription for HIV pre-exposure prophylaxis. Participants received a single dose of the MVA-BN vaccine, and the primary outcome measured was confirmed mpox infection through polymerase chain reaction testing.

Trial Participants and Results

In total, 9803 men participated in the trial, out of which 272 were diagnosed with mpox during the study period. Alarmingly, 15 of the infected individuals required hospitalization. Over a follow-up period averaging 85 days post-vaccination, results indicated that the vaccinated group had a significantly lower incidence of mpox compared to their unvaccinated counterparts. Specifically, 21 infections occurred in the vaccinated group versus 50 in the unvaccinated group, leading to an estimated vaccine efficacy of around 58%—a promising figure for public health officials.

Implications for Future Vaccination Strategies

Interestingly, the study's authors pointed out that vaccination within the first 14 days did not correlate with a decrease in mpox infections, as individuals typically require time to develop an adequate immune response. They also noted that there was no protective effect observed against STIs, reaffirming prior expectations regarding the vaccine’s scope of efficacy.

Conclusion and Call to Action

“Our findings provide compelling evidence that the MVA-BN vaccine is effective in preventing mpox infection and should be made widely available to at-risk communities,” stated the researchers confidently.

With mpox posing a growing threat to global health, this research bolsters the case for increased vaccine distribution and accessibility. As the world continues to grapple with the repercussions of the mpox outbreak, finding effective interventions like the MVA-BN vaccine could be crucial in curbing the spread of this potentially dangerous infection.

Stay informed and involved—your health could depend on it!