Can you mix-and-match COVID shots? Here’s what we know


RALEIGH, N.C.(WNCN) – CDC guidance states the COVID-19 vaccine is not interchangeable but the agency has already seen some people mix-and-match the vaccines anyway.

In a September report, the CDC explained what their research found about side effects for booster shots. From Aug. 12 to Sept. 19, 22,191 reported they’d received an additional dose through the CDC’s v-safe reporting app. Data published from those reports showed people were not always sticking to their original series. It also showed Johnson and Johnson recipients were getting extra doses although they are not yet authorized to do so.

Of the 10,601 Moderna recipients who went for a booster, 1.4 percent got the third dose of Pfizer and 0.04 percent went for Johnson and Johnson. Of the 11,412 Pfizer recipients, 1.7 percent were boosted with Moderna and 0.1 percent were boosted with Johnson and Johnson.

Of the 178 unauthorized Johnson and Johnson boosted people, 36 percent were boosted with Moderna while 37 percent were boosted with Pfizer.

The CDC’s report noted, “Insufficient data were available to determine patterns of adverse reactions after receipt of an additional dose from a manufacturer different from the primary series or for the Janssen vaccine.” That insufficient data is the problem.

“The data does suggest that boosters of the same vaccine are both effective and safe. We don’t have similar data of mixing-and-matching although the CDC does say if a vaccine was not available, say due to a shortage, you could mix the mRNA vaccines,” Dr. David Weber, UNC School of Medicine professor of epidemiology and Associate Chief Medical Officer at UNC Health Care.

Weber said it’s worth waiting for a few more days. The FDA was scheduled to discuss boosters for the Moderna and Johnson and Johnson on Oct. 14 and Oct. 15.

“In the next week or 10 days, we’ll have an answer and I do believe they are most likely to allow the boosters so I would just wait the 10 days,” Weber said.

Mixing-and-matching studies are currently underway. Top medical advisor for the White House, Dr. Anthony Fauci, told reporters at the end of September, “The mix-and-match study in which you look at Moderna as the boost against the other three, those data are now available. The J&J as the boost for the other three likely will be available literally within a week — a few days to a week. And the data on looking at Pfizer as the boost to the other three will be available somewhere in the first week, or at the most two, of October. That’s when the data will be available.”

Fauci said that data would still have to be submitted to the FDA. “So you don’t want to get ahead of the FDA, but at least that’s where the data are right now,” he said.

Before additional doses were approved for the immunocompromised, the CDC reported 1.14 million Moderna and Pfizer recipients, or less than 1 percent, went out and got an additional dose. Another 90,979, or less than 1 percent, of Johnson and Johnson recipients, also went out to get an extra dose.

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