A study examining the effectiveness of COVID-19 vaccines has been published in JAMA Network Open, weeks after it was reportedly blocked from appearing in a Centers for Disease Control and Prevention (CDC) journal.
The research found that the COVID-19 vaccine was approximately 55% effective against hospitalizations and reduced related visits to emergency departments and urgent care clinics by 50%. Public health researchers have stated that the study's methodology, known as the "test-negative design," is a reliable approach used for decades to assess vaccine efficacy.
This study was originally slated for publication in the CDC's Morbidity and Mortality Weekly Report (MMWR) this past spring. However, acting agency Director Jay Bhattacharya decided not to include it, according to Althea Grant-Lenzy, the CDC's chief science officer. Grant-Lenzy stated that this decision did not preclude the paper's publication but required the authors to address Bhattacharya's concerns. The authors retained the option to submit their work to external journals.
The "test-negative design" involves analyzing patients admitted to hospitals or seen in emergency rooms for respiratory illnesses. Researchers then compare the vaccination status of patients who test positive for COVID-19 against those who test negative.
Critics, including Bhattacharya, have raised concerns that this methodology relies on assumptions and could yield skewed results due to factors such as prior infections and patient behavior. Proponents of the design counter that it is built to account for such variables and that prior infection should be less of a concern given widespread immunity. They argue that the design offers the best available method for real-time vaccine effectiveness estimates.
Earlier this month, the CDC hosted a forum to discuss the merits and drawbacks of studies employing this methodology. Martin Kulldorff, a biostatistician and co-author of the Great Barrington Declaration, was among the speakers. Kulldorff, who previously headed a federal vaccine advisory committee, expressed concerns about the inclusion of individuals with diverse diseases in such studies and questioned the lack of longer-term vaccine evaluations.