Q&A: Can I mix Pfizer and Moderna scenes?
In this week’s edition of Covid’s Q&A, we’ll look at whether it’s okay to mix doses of different Covid-19 vaccines.
In the hope of making this very difficult time just a little less than that, each week Bloomberg Prognosis picks up one question that readers submit and sends it to an expert in the field. This week’s question comes to us from Phillip, who received the first dose of Covid-19 vaccine from Pfizer-BioNTech. As vaccine supply declines, he wonders if it is safe to get the Moderna vaccine as his second dose. He asks:
What would happen if only Moderna doses were available? Are they transitional? Is it safe to change?
This is a big question, and one that many newsletter readers raised last week. The Moderna and Pfizer vaccines are very similar. Each one uses a technology called messenger RNA (mRNA) to teach cells how to make proteins that stimulate an immune response to the virus, preparing the body to meet a potentially violent reaction.
“The Pfizer and Moderna vaccines carry the same viral genetic material, and differ only in how they are delivered to our cells once they are introduced into the our body, ”he said Ramon Lorenzo Redondo, molecular physiologist at Northwestern University’s Feinberg School of Medicine. The first dose prime the immune system, and the second helps with regeneration.
Scenes of the Moderna vaccine are being prepared in Garden City, New York.
Photographer: Johnny Milano / Bloomberg
“You can think of paper and hardcover. They are different on the outside but they have the same information, ”he says. “This genetic material, when introduced into our cells, makes them produce identical viral proteins. Therefore, they are expected to produce the same immune response. “
The issue, however, is that vaccine doses from different drug manufacturers have not yet been studied.
“There is no data on this, so you have to use judgment,” he said J.ohn Moore, vaccine researcher at Cornell University. “We would like to have data rather than use judgment. But we don’t have such good data. ”
In fact, just last week, the U.S. Centers for Disease Control and Prevention issued Updated guidance advising that in “exceptional circumstances” it is permissible to administer a different vaccine at least 28 days between doses.
Moore says that if there were no other option, it would not delay mixing the two vaccines. “We have to accept that we are in an unusual situation right now,” he said.
Postscript: Barbara of Pitcairn, Pennsylvania, wrote with a follow-up question to newsletter last week. A reader had found out if it was a problem if their second dose was delayed. Tony Moody, an infectious disease specialist at Duke University, said he may have been fine. “We know that the time between vaccines is longer than the minimum time between doses, not the maximum,” he said.
Barbara’s problem, she wrote, is that she was expecting to get her second look before the recommended three weeks for the Pfizer vaccine. “Is it okay to take four days before the recommended three weeks?” she asked.
Follow us with Moody’s.
“Vaccine tests are usually run with time windows around each bullet, and the data are analyzed together,” he said. “So we have no good way of finding out if 17 versus 21 days makes a big difference. “There is simply no data to answer Barbara ‘s question,” Moody’ said. However, he said, getting a second dose just a few days early should be fine.
“There should be nothing wrong with being a little early, and certainly better early than never,” he said. “I’m not sure I would have pushed much earlier than that. ”
Thank you all for writing in this week! Next Sunday, we’ll answer the best question we’ll get again. So if you have anything, we want to hear from you. Write to us at [email protected] – Kristen V. Brown
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