A preprint study released by Texas-based Houston Methodist suggests COVID-19 vaccine dosing is not a one-size-fits-all proposition. In the past three years, as vaccines and boosters were released, the CDC recommended all of the doses in stages based on age.
A new computational model developed by scientists at Houston Methodist revealed vaccine dosing intervals may have to be customized for individual populations so everyone receives the same level of immunity, according to an April 19 hospital press release.
The CDC voted April 19 to support changes to the COVID-19 vaccination schedule, simplifying recommendations and including a second bivalent booster authorized April 18 for senior populations and people who are immunocompromised.
"Forecasting immune response allows us to identify dosing strategies that may improve vaccine effectiveness and ensure long-term protection against the virus, based on the needs of individual subpopulations," Prashant Dogra, PhD, the study's corresponding author, said. "For example, immunocompromised patients may exhibit reduced antibody production after vaccination than what is seen in the general population."
The researchers were able to use a new math-based tool to "simulate the immune response in thousands of demographically diverse patients in a matter of minutes, allowing them to answer questions that otherwise would be expensive and time-consuming experimentally or clinically."
The computational tool helped to identify dosing protocols to "ensure protection for prolonged periods." For example, delaying the dose of the second booster "allows the immune system to recover and produce more antibodies and, therefore, provides greater protection," according to the study.
"While the model has not been calibrated to evaluate bivalent vaccines, it is of keen interest for us to see how the model predictions hold in the context of these vaccines," Dr. Dogra told Becker's. "Qualitatively, we expect the model predictions of better outcomes with longer gaps in immunocompromised patients to be still valid.”
Houston Methodist's study showed a variation of immune responses and differing protections provided by the vaccines against the original COVID-19 virus and later SARS-CoV-2 variants.
"We know that coronavirus immunity wanes over time. People who are immunocompromised, for whatever reason, whether due to advanced age or other causes, need the most support in generating a protective immune response," S. Wesley Long, MD, PhD, medical director of diagnostic microbiology at Houston Methodist, told Becker's. "It makes sense that they would need boosters before the general population. I think it is likely that we will progress to the point where COVID boosters are an annual occurrence, likely tailored to the strains circulating at that time."
All eyes are on the CDC to officially add the recently FDA-authorized second bivalent booster to its recommended protocols. Ashley Drews, MD, epidemiologist at Houston Methodist, told Becker's it can't come soon enough.
"The approval of a second bivalent booster for persons 65 and older and immunocompromised persons is needed at this time given the continued circulation of COVID-19 in the community and the waning of immunity from both prior vaccination and/or natural infection.
"It is clear that immunity wanes with time from either last vaccination or infection, and a bivalent booster dose has been shown to augment immunity in these at-risk populations," Dr. Drews said.