Potential to confuse omicron-targeting COVID booster with conventional vaccine raises concerns: report

The updated boosters provide protection against the BA.4, BA.5 variants

Health experts are reportedly concerned about potential vaccine mix-ups between the omicron-specific booster shots and vials of conventional COVID-19 vaccines which are intended to protect only against the original coronavirus strain.

The Los Angeles Times reports the issue was raised both at a Centers for Disease Control and Prevention (CDC) meeting and a gathering of the Western States Scientific Safety Review Workgroup. 

In a letter addressed to the governors of California, Nevada, Oregon and Washington state, chair Dr. Arthur Reingold said evidence supports the safety of COVID vaccines. 

"However, the Workgroup remains concerned about the potential for errors in the administration of the various COVID-19 vaccines, given that formulations for different age groups look alike," Reingold said. "To minimize the frequency of such errors, which should be reported to VAERS (Vaccine Adverse Event Reporting System), it is imperative that clear COVID-19 vaccination guidelines be disseminated to all vaccine providers. The Workgroup reiterates the importance of reporting to VAERS any suspected adverse events following receipt of a COVID-19 vaccine, whether as part of an initial series or as a booster dose and continued national safety surveillance efforts."


Pfizer omicron vaccine

This August 2022 photo provided by Pfizer shows vials of the company's updated COVID-19 vaccine during production in Kalamazoo, Mich. New booster shots are here, and social distancing guidelines are easy, but COVID-19 infections aren't going away any (Pfizer via AP, File / AP Newsroom)

VAERS is a national vaccine safety surveillance program that helps to detect unusual or unexpected reporting patterns of adverse events for vaccines. 

According to the Times, the potential for confusion stems from the color of the cap of the vials being identical, as well as vials containing the same amount of vaccine.

Citing the CDC, the paper said Pfizer shots for both omicron-specific boosters and conventional vaccines are gray and that the vial cap for both Moderna vaccines is dark blue.

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Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC), and top infectious disease expert Dr. Anthony Fauci, testify before the Senate Health, Education, Labor, and Pensions Committee on Capitol Hill in Washington, Tu (AP Photo/J. Scott Applewhite, Pool / AP Newsroom)

CDC director Dr. Rochelle Walensky said Tuesday the agency is working to pass out photos of the caps and educate vaccine administrators to "minimize confusion."

In addition, the group urged vaccination against COVID-19 for everyone who is eligible, agreeing with recommendations by the federal Advisory Committee on Immunization Practices (ACIP) for a single booster dose of an updated bivalent BA.4/BA.5 COVID-19 vaccine.


It also highlighted remaining concerns regarding the limited supply and equitable distribution of bivalent vaccines.

These boosters contain half the original vaccine, which has been used since December 2020, and half protection against omicron subvariants BA.4 and BA.5. 

COVID booster syringes

Syringes containing COVID-19 vaccines, Waterford, Mich., April 8, 2022.  (REUTERS/Emily Elconin/File Photo / Reuters Photos)

The new shots made by Pfizer are authorized for anyone 12 and older and Moderna's version is for adults. 


This marks the first update to COVID vaccines ever cleared by the Food and Drug Administration.

The Associated Press and Reuters contributed to this report.