Robert F. Kennedy, Jr. sparked swift backlash on Tuesday evening when the secretary of Health and Human Services announced the termination of nearly $500 million in federal funding and contracts supporting the development of mRNA-based vaccines.

HHS said it would coordinate a wind-down of its mRNA vaccine development activities under the Biomedical Advanced Research and Development Authority, or BARDA. The Trump administration said it decided after reviewing mRNA-related investments launched during the COVID-19 pandemic. The vaccine is used for respiratory diseases, including COVID-19, influenza, and H5N1.

“We reviewed the science, listened to the experts, and acted,” said Kennedy. “BARDA is terminating 22 mRNA vaccine development investments because the data show these vaccines fail to protect effectively against upper respiratory infections like COVID and flu. We’re shifting that funding toward safer, broader vaccine platforms that remain effective even as viruses mutate.”

The announcement was roundly criticized on social media.

Climatologist Peter Gleick‪ unloaded on Bluesky, “Those mRNA vaccine programs that RFK Jr. is killing because he claims they don’t work?The people who invented them got the f***ing Nobel Prize.And they’ve saved literally millions of lives already.”

Jake Scott, an infection diseases doctor, ‬wrote on Bluesky, “Scrapping the fastest platform we have is a reckless move rooted in a fundamental misunderstanding of vaccinology. No respiratory vaccine blocks all infections. mRNA vaccines have saved millions of lives.

Scott pointed to a CDC study that showed vaccinated adults during the 2021 Delta surge were 53 times less likely to die than those who were unvaccinated.

Audrey John, also an infectious diseases physician, wrote on Bluesky, “To say that ‘the data show these vaccines fail’ in regards to the mRNA plaform is unforgivable. For those of you that don’t remember – this is the data from a SINGLE dose. In December 2020. So good I cried in grateful tears.”

Helen Branswell, who covers infectious diseases for STAT, wrote on Bluesky, “Pandemic preparedness in the US has been leveled a crippling blow with the cancellation of multiple #BARDA contracts to help develop mRNA vaccines. No other vaccine platform produces vaccine so quickly; without mRNA, Americans will have a long wait for pandemic vax.”

Writer Rebecca Fishbein‪ wrote on Bluesky, “I believe one of the new mRNA vaccines was expected to treat colon cancer, and another had the potential to keep pancreatic cancer from recurring. That’s what they’re taking away.”

Laura Weiss‪, a writer who covers social issues including health justice at the New Republic, wrote on Bluesky, “WHAT, WHAT, WHAT ARE WE DOING!!!”

Anna Merlan‪, journalist at Mother Jones, wrote on Bluesky, “We could have had cancer vaccines, and instead the United States will contribute nothing whatsoever to mRNA research, condemning millions of people worldwide to unnecessary illness and death.”

And Charles Gaba‪, a health care data analyst, simply wrote, “Welp.”