As widely-anticipated decisions about COVID-19 vaccine boosters come out from U.S. agencies today, insights from an independent research study provide proof the importance of boosters for all adults.
Antibody levels following the Pfizer-BioNTech COVID-19 vaccine vary by age and sex but, in general the levels of antibody decreased dramatically within the first six months, according to an ongoing study led by Texas Biomedical Research Institute (Texas Biomed) and the University of Verona in Italy.
The study showed that the total levels of antibodies against SARS/CoV-2 varied across ages and between men and woman. Specifically, individuals under the age of 65 had more than twice the amount of antibodies than individuals 65 years old and older during the six months after vaccination. Women had higher levels of antibodies than men, especially women under the age of 65. Importantly, however antibody levels were lower by more than half in six months from the highest levels for all participants in the study.
“While we can see how vaccines have helped people stay out of the hospital and help prevent life-threatening illnesses, antibody levels are rapidly declining for all people, regardless of age or sex,” said Brandon Michael Henry, MD, who was a physician scientist at Texas Biomed and co-led the study with colleagues from Italy. “Our study offers further evidence that booster shots for all adults will be important to keep antibody levels in check so that we can continue to develop a powerful immune response to COVID-19 and reduce the risk of COVID-19 deaths.”
These findings were based upon 787 healthcare workers from Verona, Italy who were given two doses Pfizer BioNTech COVID-19 vaccine. They ranged between 21 and 75. The levels of their antibodies were determined before the vaccination, after the second dose, and at one three and six months after the second shot. Henry presented his research at the 9 9 annual Vaccine Development Center of San Antonio conference on Nov. 11. The paper was accepted for publication in the Journal of Medical Biochemistry.
Henry and his collaborators believe that hormones are the cause for the sex-related differences that are so significant. The immune system is naturally suppressed by testosterone, which is more common in men than in women. However, estrogen is more prevalent in women, has been shown to boost immune response. Additionally, some genes that encode for certain immune proteins are located on the X chromosome, and since women have two X chromosomes this could boost immune activity.
In normal circumstances the X chromosome is active while the other one is generally inactive, but there is evidence to suggest that immune-related genes are active on that redundant chromosome and aid in boosting immune responses in women.”
Brandon Michael Henry, MD is a physician scientist and postdoctoral researcher at Texas Biomed.
However women regardless of age still saw their levels of antibody fall by more than 50% from peak by six months post vaccination.
Henry has also conducted systematic reviews that showed similar results for gender and age. Henry and his colleagues devised methods to standardize research results on antibody levels, by analyzing the percentage change in antibody levels, across 32 studies covering more than 5,000 individuals.
Henry states that “we have observed that throughout the epidemic that more elderly and men suffer from the worst effects of COVID-19.” “These studies suggest lower immune responses to SARS-CoV-2 as a contributing factor to this phenomenon.”
Henry said that a decrease in antibody levels doesn’t necessarily mean that vaccines are no longer effective. Different types of antibodies have different roles in preventing a mild breakthrough infection versus severe illness. Vaccination is crucial because the antibodies that prevent severe diseases seem to work in all populations even when they are lower in levels. However, since the antibodies decrease over time, booster doses are able to help maintain adequate levels of these life-saving antibodies.
On Friday, November. 19, the U.S. Food and Drug Administration (FDA) approved boosters for all adults. The Centers for Disease Control and Prevention (CDC) is scheduled to issue its official recommendation in the near future. Prior to that, the FDA approved boosters and recommended them for certain populations. Several states have already moved forward with offering boosters for all adults for six months following vaccination.
Salvagno, G.L., and. (2021) Total Anti-SARS-CoV-2 Antibodies Tested 6 Months Following Pfizer-BioNTech COVID-19 Vaccination for Healthcare Workers. Journal of Medical Biochemistry. doi.org/10.2139/ssrn.3915349.
Content Source: https://www.news-medical.net/news/20211121/Study-underscores-why-COVID-19-vaccine-boosters-are-important-for-all-adults.aspx