rsv vaccine
Nearly 130 pregnant women and 25 children under age 2 were given the wrong respiratory syncytial virus (RSV) vaccine, according to the Centers for Disease Control and Prevention (CDC).

The children were mistakenly administered either Pfizer's Abrysvo or GSK's (formerly GlaxoSmithKline) Arexvy RSV vaccines. Both are approved by the U.S. Food and Drug Administration (FDA) for adults ages 60 and older — but not for children or babies.

For babies, the CDC recommends a monoclonal antibody — nirsevimab (Beyfortus) — produced by AstraZeneca and Sanofi. The CDC also recommends Beyfortus for children ages 8-19 months who are at increased risk of severe RSV.

Although Arexvy and Abrysvo are approved for older adults, only Abrysvo is approved for pregnant women to prevent RSV in their babies. All of the 128 pregnant women who received the wrong vaccine were administered Arexvy.

RSV is a common respiratory virus that usually causes mild, cold-like symptoms.

The virus has recently received a lot of media attention as therapies protecting against it "are now sort of a boon" for Big Pharma, according to Dr. Meryl Nass, internist and member of the Children's Health Defense scientific advisory committee.

The CDC said in a Jan. 22 Clinical Outreach and Communication Activity alert that the agency had detected the administration errors through the Vaccine Adverse Event Reporting System (VAERS).

Most of these errors occurred in outpatient settings when treating babies under 8 months old, the CDC said.

Commenting on the news, Nass said it was a "big problem" that vaccines only approved for use in adults were administered to babies. "It's also a big problem that pregnant women were given a vaccine with no approval data for its use during pregnancy."

"Clearly, the labels on these products were not very good and did not make clear what they were for," Nass told The Defender. "That means the FDA screwed up and maybe the manufacturers screwed up, creating a situation where they'd be misused."

Nass noted that Pfizer and GSK chose names for their RSV vaccines starting with the letter "a," which may have led to the mishap of giving pregnant women the wrong shot. "Why did they do that?" she asked.

"Part of FDA's job is to make labeling clear and not mix up products," Nass said. "They failed in that duty."

In its alert, the CDC said most of the administration error reports in VAERS did not include descriptions of adverse events. The few adverse events that did occur were recorded as "nonserious."

"CDC, FDA, and other federal agencies continue to monitor the safety of RSV vaccines and reports of vaccine administration errors and will share information with the public as it becomes available," the CDC said.

The agency also issued recommendations for clinicians who had administered the incorrect vaccine, including that children who got one of the two RSV vaccines should be given a dose of Beyfortus — the monoclonal antibody that they were supposed to be given — and that babies of the pregnant women who mistakenly got Arexvy should be given a dose of Beyfortus during RSV season if younger than 8 months.

The CDC alert did not specify the data it used for making these recommendations or warn of any potential negative effects from administering multiple, differing RSV vaccines.

The CDC said, "Healthcare providers and facilities should ensure use of the correct RSV prevention product in the correct population and take actions to prevent vaccine administration errors."

The alert included a link to a healthcare provider toolkit on preventing such errors.

The CDC's press office did not immediately respond to a comment request from The Defender about how the mistakes were made.

Suzanne Burdick, Ph.D., is a reporter and researcher for The Defender based in Fairfield, Iowa.