CDC Recommends Mpox Vaccination Amid Spread of Deadly Strain in Africa

Growing Concern Over Mpox Outbreak

The CDC is urging at-risk populations, including sexually active gay and bisexual men and individuals with HIV, to get vaccinated against mpox. This comes as a more lethal strain of the virus spreads in the Democratic Republic of the Congo (DRC). With summer travel and Pride events on the horizon, timely vaccination is crucial to prevent another large-scale outbreak.

Mpox Strain in the DRC

Mpox cases in the DRC have surged, with nearly 20,000 suspected cases and 975 deaths reported between January 2023 and April 2024. Unlike previous outbreaks that primarily affected children, recent cases show sexual transmission, especially in cities. The strain, known as Clade I, is more deadly and poses a significant risk of spreading beyond Africa.

U.S. Preparedness and Response

Although the U.S. hasn’t detected Clade I mpox, the CDC continues to monitor and test for it. Current mpox cases in the U.S. remain low, with most infections occurring among unvaccinated individuals. The Jynneos vaccine, effective against both Clade I and II strains, is recommended for those at risk. Despite availability, only a quarter of eligible individuals are fully vaccinated.

Call for Global Action

The CDC emphasizes the need for global cooperation to ensure vaccine availability in Africa. As the virus doesn’t recognize borders, containing the outbreak in the DRC is essential to prevent global spread. Enhanced surveillance and vaccination efforts are crucial to mitigate the risk.

Findings from the Netherlands and Sweden

Recent studies in the Netherlands and Sweden revealed that antibody levels in individuals receiving two doses of the Jynneos vaccine dropped significantly within months. However, those vaccinated against smallpox in childhood maintained higher antibody levels. This suggests that the non-replicating Jynneos vaccine may not evoke as robust an immune response as the traditional smallpox vaccine.

Divergent Views on Booster Necessity

Dr. Klara Sondén from the Public Health Agency of Sweden highlighted the potential need for booster doses to maintain long-term immunity. Contrarily, Dutch researchers cautioned against premature conclusions, emphasizing that waning antibodies do not necessarily equate to diminished protection. They pointed out that immunity involves other factors, like T-cell responses, and stressed the need for ongoing clinical monitoring to correlate infection rates with antibody levels.

CDC Perspective on Vaccine Effectiveness

The CDC’s real-world findings suggest that despite declining antibody levels, overall immunity may not be waning. They noted the importance of innate and cell-mediated immunity, which could play a critical role in preventing mpox infections. The robustness of the memory or recall response after exposure might be more crucial in determining the disease outcome than antibody levels alone.

Key Points to Remember

• Antibodies fall quickly post-Jynneos vaccination but remain higher in those with past smallpox vaccination.
• There’s debate on the need for booster doses due to the complexity of immunity.
• The CDC highlights other immune factors beyond antibodies that contribute to protection.

These findings underscore the importance of continued research and monitoring to make informed decisions about mpox vaccination strategies.

By staying informed and proactive about vaccination, you can help protect yourself and your community from the growing threat of mpox.