US health agencies are facing criticism from scientists and doctors over decisions to limit or halt publication of medical research, raising questions about transparency in public health communications.

According to reports, the Food and Drug Administration (FDA) reportedly prevented publication of studies examining the safety of vaccines against shingles and Covid-19. The specific details and timeline of these decisions have not been fully disclosed by the agency.

Separately, the Centers for Disease Control and Prevention (CDC) halted publication of a study on Covid booster effectiveness. The decision was made by the agency's top acting official, though the circumstances surrounding the halt remain unclear.

Additional concerns have emerged regarding research at the National Institutes of Health (NIH), where studies have reportedly been terminated or denied approval based on the inclusion of certain keywords such as "hesitancy" and "misinformation."

Critics argue these actions could damage public health by limiting access to important scientific information. They contend that open communication about medical research findings is essential for informed public health decision-making.

The extent of federal agencies' oversight of research communications has become a point of debate within the medical and scientific communities, with some calling for greater transparency in how publication decisions are made.