CDC study shows COVID shot benefits; Trump official blocks release

CDC published an MMWR study last month on this year's flu shot effectiveness.

It used a test-negative case-control design.

That design was widely used in hundreds of COVID-19 vaccine studies during the pandemic.

HHS says CDC leaders routinely review MMWR papers and raise methodology concerns before publication.

Bhattacharya wanted a different method, and CDC scientists are working to address the concerns.