The Centers for Disease Control and Prevention (CDC) has canceled publication of a scientific report showing the efficacy of the COVID-19 vaccine, according to media reports.

The Washington Post, which first reported the news, says the report, initially scheduled to be published in the CDC’s Morbidity and Mortality Weekly Report on March 19, showed the COVID-19 vaccine cut the likelihood of emergency department visits and hospitalizations in half this past winter.

The report had cleared the agency’s scientific review process before being delayed by acting CDC Director Jay Bhattacharya, MD, PhD, over concerns about the methodology. But the same methodology has long been used by the CDC to evaluate vaccine effectiveness for respiratory viruses and was used in a study on the flu vaccine published last month in MMWR.

In response to a query from CIDRAP News, a CDC official did not address the blocked report specifically but said the agency has to apply the “highest standards of scientific rigor” to the information it publishes.

“Responsible science requires careful review. Taking time to ensure analyses are methodologically sound and clearly communicated is always preferable to risking error,” the official said.