Covid-19 vaccines roughly halved the chances that a US adult would need to visit the emergency room or be hospitalized with their infections last fall and winter, according to two sources familiar with the findings of a new study. But you won’t hear about it from the agency that led the research: the US Centers for Disease Control and Prevention.

The current head of the CDC, Dr. Jay Bhattacharya, who’s also director of the US National Institutes of Health, blocked the publication of those findings in the CDC’s flagship journal, the Morbidity and Mortality Weekly Report, according to the sources.

The authors of the study received an official rejection letter from the journal on Tuesday, one source said, even though the study had cleared internal reviews and had been scheduled for publication.