Antibodies generated by the mpox vaccine diminish significantly within 6 to 12 months, underscoring the need for booster doses to maintain robust protection against the virus. The research, led by Dr. Ai-ris Yonekura Collier from Beth Israel Deaconess Medical Center (BIDMC), highlights the importance of completing the recommended two-dose vaccine series. This is particularly crucial given the emergence of a new, potentially more severe, strain of mpox in the Democratic Republic of Congo, which has prompted the World Health Organization to declare a public health emergency of international concern.
Declining Immunity Post-Vaccination
The study, published in the Journal of the American Medical Association, assessed immune responses over 12 months in 45 individuals who received mpox vaccinations during the 2022 outbreak or had a confirmed mpox diagnosis. Participants received either one or two doses of the Jynneos vaccine. The research team, led by Collier and Dr. Dan Barouch, director of BIDMC's Center for Vaccine and Virology Research, compared antibody and T-cell responses at baseline, three weeks, and then every three months for a year. The results indicated that vaccine-induced protection largely waned within six to 12 months.
Implications for Public Health
"Our study highlights the importance of completing the recommended two-dose mpox vaccine, whether subcutaneous or interdermal, to boost immunity -- regardless of the time between doses," said Dr. Yonekura Collier. The findings suggest that individuals vaccinated during the 2022 outbreak may require a booster dose to ensure continued protection, especially with the ongoing risk of new outbreaks. As of September 1, the new mpox outbreak in Africa has resulted in over 5,265 confirmed cases, 18,737 suspected cases, and 617 deaths across 14 African countries, according to the WHO.
Study Details and Future Research
The study monitored antibody and T-cell responses in participants who received the Jynneos vaccine. Public health officials initially prioritized vaccination for high-risk groups, including individuals with multiple sexual partners, men who have sex with men, healthcare workers, lab personnel, and travelers to regions with identified mpox cases. Dr. Barouch noted that larger human studies are necessary to evaluate the vaccine's long-term effectiveness. The research was supported by grants from the National Institutes of Health, the Massachusetts Consortium for Pathogen Readiness, and the NIAID Division of Intramural Research.
Mpox Outbreak Context
Mpox, previously known as monkeypox, spreads primarily through close skin-to-skin contact, especially during sexual activity. Symptoms include fever, painful rashes or sores, and swollen lymph nodes. The 2022 mpox outbreak rapidly spread to countries outside Africa, a phenomenon not previously observed. The emergence of a new strain in the Democratic Republic of Congo underscores the ongoing global health threat posed by the virus.
