by This winter, for the first time, two vaccines were available to protect against respiratory syncytial virus, which is particularly dangerous for older adults and babies. Only one of them, Abrysvo, manufactured by Pfizer, was approved for pregnant womenand it wasn’t for small children either.
The distinction apparently went unnoticed by some doctors and pharmacists.
At least 128 pregnant women mistakenly received the alternative vaccine, GSK’s Arexvy, and at least 25 children under age 2 received the vaccine, the Centers for Disease Control and Prevention has reported. warned.
Dr. Sarah Long, a pediatric infectious disease physician and agency consultant, said she was “surprised” by the reports. “It’s very concerning that this is happening,” she said.
Arexvy has not been tested in pregnant women or children, so information on its effects in those groups is limited. Serious damage from the bugs has not yet been confirmed, but the outcome is unknown in most reported cases.
Based on the available data, Dr. Long said she was more concerned about young children who received the RSV vaccine than about pregnant women who received Arexvy or their babies. Evidence from animal testing “strongly suggests” that Arexvy could exacerbate RSV infection in children under 2 years of age, rather than mitigate it. according to the Food and Drug Administration.
To prevent this, the CDC has recommended that children who received either vaccine in error also receive nirsevimab (sold as Beyfortus), a monoclonal antibody that provides strong immune protectionwhile the RSV season lasts.
Up to 80,000 children Children under 5 years of age are hospitalized with RSV infections each year in the United States, and the virus is a leading cause of death in children worldwide.
In 2022, GSK stopped clinical trials of a version of its vaccine in pregnant women after a safety review indicated an increased risk of premature birth. The company also found an increase in neonatal deaths, but said they were a consequence of premature births.
GSK is still monitoring participants in those trials and sharing the data with the FDA, said Alison Hunt, a company spokeswoman.
In the Pfizer trial, Abrysvo also showed a slightly increased risk of preterm birth up to 37 weeks of gestation, but the increase was not statistically significant.
Still, concerned about the possible risk of premature birth, the FDA approved Abrysvo only for pregnant women between 32 and 36 weeks of gestation. (The goal is to produce antibodies in women that can be transmitted to babies, protecting them immediately after birth.)
CDC advisors further narrowed the window by recommending vaccines for pregnant women only from September to Januarywith the aim of protecting babies born during the peak RSV season.
“In reviewing the data, we feel somewhat conservative,” said Dr. Camille Kotton, a physician at Massachusetts General Hospital and one of the agency’s scientific advisers.
“If there was a problem with preterm birth, having it in the last eight weeks of pregnancy would probably have less impact than early in pregnancy,” he said.
Some babies who received the RSV vaccine by mistake should have received nirsevimab. The GSK vaccine appears to have been given to some pregnant women because the Pfizer vaccine was not as widely available and pharmacists thought they were interchangeable.
Amy Gardner, 39, a former kindergarten teacher in Cleveland, Tennessee, said she tried to locate Pfizer’s RSV vaccine at several pharmacies for her pregnant daughter. In mid-September, the last day her daughter was eligible to receive the vaccine, she found a pharmacy that said it had the vaccine in stock, Gardner said.
But his daughter received Arexvy.
“We’re all human, but there has to be more checks and balances than this,” Gardner said. She believes the injection caused her daughter to go into premature labor a few hours later.
The errors were reported to a federal database called the Vaccine Adverse Event Reporting System. Those administering the vaccines may have been confused in part by the similarity of the two names, experts said.
“It’s just horrible. Why, why did they do this?” Dr. Long said. “A lot of people were paid a lot of money to come up with these names, and I don’t understand them.”
Dr. Kotton urged the FDA to encourage companies to give similar products clearly distinguishable names. “When there is a concomitant release of vaccines, whenever possible, it would probably be good to have different names,” he said.
Dr. Long said she was baffled by the fact that young children were receiving RSV vaccines. Because they are not approved for children, pediatricians’ offices, which typically administer vaccines, should not have had any in stock.
“It’s important to find out how that happened, because we don’t want it to happen again,” he said.
