Studies show that the effectiveness of the Mpox vaccine decreases after one year
Mpox vaccine: Two independent studies have shown that the efficacy of Bavarian Nordic’s vaccine against the deadly infectious disease declines “to undetectable levels” within six to twelve months. The vaccine, administered in two doses four weeks apart, is the first injection against Mpox to be prequalified by the World Health Organization (WHO).
The first study published in the open access medical journal Eurosurveillance shows that “Orthopoxvirus-specific binding and MVA-neutralizing antibodies decreased to undetectable levels one year after vaccination in at-risk individuals who received two doses of MVA-BN.”
The study was led by researchers at Erasmus University Medical Center in the Netherlands. The researchers called for continued monitoring to understand the impact of declining antibody levels.
Modified Vaccinia Ankara-Bavarian Nordic or MVA-BN vaccine is indicated for active immunization against smallpox, Mpox, and related orthopoxvirus infections and diseases in all adults 18 years of age and older.
In the first study, researchers investigated 99 high-risk active gay, bisexual or other men who have sex with men (GBMSM) and 19 laboratory workers in the Netherlands in 2022 and 2023. Participants included those born both before and after 1974, when the smallpox vaccine was no longer administered in the Netherlands.
The study concluded that “while antibodies induced by historical smallpox vaccination with first- or second-generation vaccines can be detected for decades, we found a rapid decline in antibodies in vaccine recipients without preexisting immunity.”
The second study, which was published on a preprint server and was not peer-reviewed, showed that “MVA-BN vaccine generated mpox serum antibody responses that greatly decreased after 6 to 12 months.”
The study was led by researchers at Beth Israel Deaconess Medical Center at Harvard Medical School (USA). They collected serum samples from 45 participants who had been infected with Mpox or had received one or two doses of MVA-BN.
For the study, Dan Barouch, director of the Center’s Center for Virology and Vaccine Research, reported that Mpox antibodies generated by the vaccine greatly decreased after 6 to 12 months.
After one year, antibody levels in participants who received two doses of the Mpox vaccine were comparable to or lower than the peak antibody responses in people who received only one dose. MVA-BN, developed in 2019, is a live attenuated vaccinia virus vaccine.
A recent study published in the British Medical Journal showed that vaccine efficacy estimates for two doses of the vaccine range from 36 to 86 percent. The study showed that a single dose is only 58 percent effective in preventing Mpox.
(With inputs from IANS)
Disclaimer:
The information contained in this post is for general information purposes only. We make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the post for any purpose.
We respect the intellectual property rights of content creators. If you are the owner of any material featured on our website and have concerns about its use, please contact us. We are committed to addressing any copyright issues promptly and will remove any material within 2 days of receiving a request from the rightful owner.