COVID vaccine study raises questions about boosters

SANDUSKY — It turns out that COVID-19, and the efforts to fight it, still have some mysteries for scientists to puzzle over. A new Cleveland Clinic study of vaccinations of thousands of its employees had a surprising finding: Employees with a high number of vaccine doses, including boosters, were more likely to contract COVID-19. "The study found that the longer it has been since last exposure to the virus by infection or vaccination, the higher the risk of acquiring COVID-19. It also found that the higher the number of vaccine doses an individual previously received, the higher the risk of contracting COVID-19," according to a statement from the Cleveland Clinic summarizing the study. The clinic said officials don't know what to make of the fact that the more-immunized employees also caught COVID-19 more often. "It is unclear, at this time, why this was observed and how it should be interpreted, and more research is needed to either confirm or refute this finding. It's important to note that this paper has not yet been peer-reviewed," the statement said. The study does not contradict massive evidence showing that the COVID-19 vaccination campaign saved many lives in the U.S. and abroad. Vaccines remain "very effective" against severe disease and death, the study cites. And even critics of the U.S. Food and Drug Administration's fast decision to approve the newest COVID-19 booster agree that COVID vaccinations saved many lives. But the study apparently raises questions about whether the Biden administration's strategy of numerous booster shots is effective and whether the FDA acted hastily in approving the latest booster, the bivalent vaccine that became available in the fall. "Vaccination remains an important preventive measure against COVID-19, and it's important to study new vaccines as they are released. Vaccination is still the best way to prevent severe illness and hospitalization from COVID-19," the statement from the clinic says. The two mRNA vaccines, from Moderna and Pfizer, were released as a two-shot series. Since then, three booster shots have been offered. So anyone who took advantage of every mRNA shot that was offered has now received five mRNA shots. The Cleveland Clinic study was carried out on about 51,000 employees. It was aimed at evaluating the latest booster, the bivalent shot. It concluded that the shot offered "modest protection" against COVID-19. "The risk of COVID-19 also varied by the number of COVID-19 vaccine doses previously received. The higher the number of vaccines previously received, the higher the risk of contracting COVID-19," says the study, "Effectiveness of the Coronavirus Disease 2019 (COVID-19) Bivalent Vaccine," which is available at medrxiv.org. "The association of increased risk of COVID-19 with higher numbers of prior vaccine doses in our study was unexpected," the study says. But the report also says that two other studies also show a connection between multiple vaccine shots and an increased risk of getting COVID-19. "A large study found that those who had an omicron variant infection after previously receiving three doses of vaccine had a higher risk of reinfection than those who had an omicron variant infection after previously receiving two doses of vaccine," it states. "Another study found that receipt of two or three doses of an mRNA vaccine following prior COVID-19 was associated with a higher risk of reinfection than receipt of a single dose." "We still have a lot to learn about protection from COVID-19 vaccination, and, in addition to a vaccine's effectiveness, it is important to examine whether multiple vaccine doses given over time may not be having the beneficial effect that is generally assumed," it says. The Register asked the Cleveland Clinic for an interview of Dr. Nabin K. Shrestha, the study's lead author and an infectious disease expert at the clinic. A spokeswoman, Andrea Pacetti, said Shrestha is currently unavailable. Instead, Pacetti released a statement, which outlined the study's main findings and which offered qualifiers. The study was done for a relatively healthy population with no children, few elderly people and few immunocompromised people, so caution is needed in interpreting it, the statement said. A strength of the study is that it has a large sample size, the paper notes. Dr. Jeffrey Singer, a senior fellow at the Cato Institute in Washington, D.C., describes himself as "pro-vax" and says he got the initial two COVID-19 doses and a booster shot. He also has had COVID-19 twice. He said he agrees evidence suggests the vaccine saved many lives. But Singer said the Cleveland Clinic results boost critics such as himself who believed the FDA rushed through the approval process for the latest booster. In previous approvals for COVID-19 vaccinations, Singer said, the FDA convened a panel of experts, who weighed the evidence and voted on whether to recommend the vaccine. That was followed by decisions made by the FDA itself and by the CDC. But with the bivalent vaccine, the decision was made in a matter of hours, without the expert panel weighing in, after the Biden administration already had announced a new booster was coming. The latest booster also skipped clinical trials with humans, relying on a test of antibody responses in mice, Singer said. Singer noted that two senior FDA vaccine officials, Marion Gruber and Phil Krause, resigned in protest in 2021 over how the government has handled the approval of COVID-19 vaccine boosters. The pair also co-authored a paper with other scientists arguing that boosters are unnecessary and that boosters might result in unintended adverse effects and lessen confidence in the original shots. Defenders of the process used to quickly approve the latest booster have pointed out that new flu shots are quickly developed every year. Singer, who said he got the latest flu shot, argues that the analogy fails in two ways. First, flu vaccines are developed using the latest strains during the cold weather months in the southern hemisphere, and so they are up to date. Second, the flu vaccine is based on an old technology that's been used for many years, so long trials are considered a waste of time. By contrast, mRNA vaccines are new, and they ought to be tested, Singer contends.