A significant study on COVID-19 vaccine effectiveness, previously withheld from a government health journal, has now been published, revealing crucial insights into its protective capabilities.
The research, appearing Tuesday in JAMA Network Open, found the vaccine to be approximately 55% effective against COVID-19-associated hospitalizations. It also demonstrated a 50% reduction in COVID-19-related visits to emergency departments and urgent care clinics.
While its findings align with existing research on vaccine efficacy, the paper garnered public attention due to its controversial past. Political appointees within the Trump administration had previously prevented its inclusion in a Centers for Disease Control and Prevention (CDC) publication.
Their rationale centered on concerns that the study’s design was susceptible to false assumptions, potentially yielding inaccurate results. However, many public health researchers contend that the methodology is a reliable, decades-old approach that offers the most effective means of assessing current vaccine performance.
“It is critical that we continue to characterize and publish estimates of vaccine effectiveness in populations with changing immunity against evolving viral strains,” wrote Natalie Dean, an Emory University biostatistics expert, in a commentary accompanying the study’s publication.
The research was initially slated for publication this spring in the CDC’s flagship journal, Morbidity and Mortality Weekly Report. Despite being cleared by 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. Grant-Lenzy clarified that Bhattacharya’s decision did not preclude publication entirely but required the authors to address his concerns. She added that the authors retained the freedom to submit their study to external journals.
The study employed a “test-negative design,” a methodology that examines individuals admitted to hospitals or emergency rooms with respiratory illnesses. Researchers then determined vaccination status and calculated the likelihood of a positive COVID-19 test among vaccinated patients compared to unvaccinated ones. This approach has been peer-reviewed and published in several esteemed journals, including Pediatrics and The New England Journal of Medicine.
Bhattacharya, however, argued that this methodology relies too heavily on assumptions and could produce results skewed by factors such as prior infections and varying patient behaviors.
Proponents of the design counter that it is specifically structured to account for differences in who seeks care, and that prior infection is less of a concern given the widespread exposure to the coronavirus among Americans. They acknowledge that no study design is flawless, but note that officials at the U.S. Department of Health and Human Services have not proposed a viable alternative for obtaining real-time vaccine-effectiveness estimates.
Earlier this month, the CDC hosted a forum to discuss the merits and drawbacks of such studies. The panel included Dean and other experts who primarily highlighted the methodology’s strengths. However, it also featured a critic, Martin Kulldorff, a biostatistician and co-author of the Great Barrington Declaration, an October 2020 letter that argued pandemic shutdowns caused irreparable harm.
Kulldorff, who was appointed by the U.S. Health Secretary Robert F. Kennedy Jr. as head of a federal vaccine advisory committee before moving to the HHS planning and evaluation office, contended that such studies should not include individuals with different diseases.
He also questioned why longer-term studies were not utilized to evaluate COVID-19 vaccines. To this, one person in the audience retorted, “We were in a pandemic! That’s why!”
