A COVID-19 vaccine study that was kept out of a government health journal has found a new home — and its findings are now available to the public.
The research, published Tuesday by JAMA Network Open, found that COVID-19 vaccines are approximately 55% effective at preventing hospitalizations related to the virus. The study also showed that vaccinated individuals were 50% less likely to visit an emergency department or urgent care clinic for COVID-19-related illness.
While the results themselves aren’t groundbreaking — scientists have consistently shown that COVID-19 vaccines provide protection — the study attracted widespread attention after Trump administration political appointees blocked it from being published in a Centers for Disease Control and Prevention journal.
Those officials raised concerns that the study’s methodology was too susceptible to flawed assumptions that could skew the results. However, many researchers in the public health field argue the approach is a well-established and dependable method that has been in use for decades, and that it remains the most effective tool for measuring how well vaccines are performing in real time.
Natalie Dean, a biostatistics expert at Emory University, wrote a commentary published alongside the study Tuesday, stating: “It is critical that we continue to characterize and publish estimates of vaccine effectiveness in populations with changing immunity against evolving viral strains.”
The paper had originally been slated for publication this spring in the Morbidity and Mortality Weekly Report, the CDC’s primary publication. Although it cleared the agency’s Office of Science, it was flagged by acting agency Director Jay Bhattacharya, according to Althea Grant-Lenzy, the CDC’s chief science officer, who spoke about the matter in a recent interview.
Grant-Lenzy clarified that Bhattacharya’s decision wasn’t a permanent ban on publication, but rather a requirement that the study’s authors address his concerns. She noted that the authors were free to submit the research to journals outside the CDC.
The methodology at the center of the controversy is known as “test-negative design.” It examines patients who were admitted to hospitals or visited emergency rooms with respiratory symptoms, then compares the rate of positive COVID-19 tests between vaccinated and unvaccinated patients.
This type of study has appeared in respected publications such as Pediatrics and the New England Journal of Medicine, following peer review by field experts.
Bhattacharya has maintained that the methodology leans too heavily on assumptions and could be distorted by variables such as prior coronavirus infections and behavioral differences among patient groups.
Supporters of the approach counter that the design is specifically built to account for differences in who seeks medical care, and that prior infection is less of a concern given how widespread coronavirus exposure has been in the United States. They also point out that officials at the U.S. Department of Health and Human Services have not put forward a practical alternative for tracking real-time vaccine performance.
Earlier this month, the CDC hosted a forum to examine the strengths and weaknesses of this type of research. A panel assembled in a CDC auditorium featured Dean and two others who largely defended the methodology, as well as one critic: Martin Kulldorff, a Swedish-born biostatistician who co-authored the Great Barrington Declaration alongside Bhattacharya. That October 2020 letter argued that pandemic-era shutdowns were causing lasting harm.
U.S. Health Secretary Robert F. Kennedy Jr. previously appointed Kulldorff to lead a federal vaccine advisory committee. Kulldorff later stepped down from that role to become chief science officer at the HHS planning and evaluation office.
During the forum, Kulldorff questioned why the study design included patients with varying illnesses and why longer-term research wasn’t used to evaluate COVID-19 vaccines. His remarks drew a sharp response from the audience — someone called out, “We were in a pandemic! That’s why!”
