CDC Reports Errors in RSV Vaccines Given to Pregnant Woman, Monoclonal Antibody Shots to Children

A new problem involving the RSV (Respiratory Syncytial Virus) vaccines given to adults over age 60 and monoclonal antibody shots given to infants and children has been highlighted in a recent emergency newsletter called the U.S. Centers for Disease Control and Prevention (CDC) Clinician Outreach and Communication Activity, which is distributed to health care providers.¹

In the United States, there are two RSV vaccines licensed by the U.S. Food and Drug Administration (FDA). One is called Abrysvo manufactured by Pfizer, Inc. and FDA approved for people over 60 years old and for pregnant women between 32 and 36 weeks gestation. The second RSV vaccine is called Arexvy manufactured by GSK plc and FDA approved for people over the age of 60.

In addition, a monoclonal antibody drug called Nirsevimab (also known as Beyforus) manufactured by Sanofi SA in partnership with AstraZeneca plc is FDA approved for babies and children up to two years of age.² Beyforus is administered as a shot into the thigh muscle.³

Since the FDA licensed the RSV vaccines and the Nirsevimab monoclonal antibody shot, the CDC and FDA have received reports of Abrysvo or Arexvy RSV vaccines being administered in error to young children. In addition, the CDC and FDA have also received reports of the Arexvy RSV vaccine being administered in error to pregnant women.⁴

Ann Philbrick, PharmD, associate professor at the University of Minnesota College of Pharmacy stated:

I would surmise it was a combination of all three products being released in short succession of each other and lack of knowledge of the specifics of each product.”⁵

These errors were unfortunate, but they do provide an important learning opportunity for those that provide vaccines. Locally, whichever healthcare facility made the error will hopefully review all steps of their process to try to mitigate the chances of repeating the error, though they are not mandated to do so.”⁶

VAERS Detected Errors in Administration of RSV Vaccine

According to the CDC’s newsletter, as of Jan. 17, 2024 the number of error reports received by VAERS suggests that there were 25 reports of administration of the wrong RSV product to young children less than two years of age and 128 reports of errors in administration of RSV vaccines to pregnant women.⁷

VAERS data showed that most reports of administration errors in young children occurred in infants under eight months old. Administration errors for both young children and pregnant women occurred in outpatient settings such as doctor’s offices, while administration errors of the Arexvy RSV vaccine in pregnant women occurred in pharmacies. The CDC’s newsletter stated that “Most of these administration error reports described no adverse event. When an adverse event was concurrently reported to VAERS, most reports were classified as non-serious.”⁸

CDC Issues Guidelines for Health Care Providers Who Err in Administration of RSV Vaccines and Monoclonal Antibody Shots

The CDC’s newsletter outlines recommendations for vaccine providers about what to do if they administered the wrong RSV vaccine or monoclonal antibody shot to a patient. The recommendations can be found here.

Steve Grapentine, PharmD, a pediatric infectious disease pharmacist at University of California San Francisco’s Benioff Children’s Hospital said:

If a serious reaction were to occur, that would likely happen within the first 15 minutes after vaccine administration. Fortunately, most vaccines are well-tolerated even when given incorrectly.”

But Dr. Grapentine also noted:

None of these products are interchangeable. Arexvy and Abrysvo are each dosed in micrograms and technically contain the same amount of RSV vaccine, but you cannot make direct comparisons between the two. Vaccine and medication strengths are unique to that specific product. Beyfortus is dosed in milligrams and not technically a vaccine, so it’s even more different.⁹

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