Questions: Can I mix Pfizer and Modern images?
In this week’s edition of Covid’s questions and answers, we look at whether it’s okay to mix doses of different Covid-19 vaccines.
Hoping to make this time so confusing a little less, each week Bloomberg Prognosis chooses a question submitted by readers and puts it to an expert in the field. This week’s question comes to us from Phillip, who has received his first dose of Povizer-BioNTech’s Covid-19 vaccine. As vaccine supplies dwindle, one wonders whether it is safe to receive the Modern vaccine as a second dose. He asks:
What if only doses of Moderna are available? Are they interchangeable? Is it safe to change?
This is a big question that many other newsletter readers posed last week. The Modern and Pfizer vaccines are very similar. Each uses a technology called messenger RNA (mRNA) to teach cells how to produce a protein that triggers an immune response to the virus, preparing the body for a possible encounter with it in nature.
“Pfizer and Moderna vaccines carry exactly the same viral genetic material and only differ in the way they are delivered to our cells once they are introduced into our body,” he says. Ramon Lorenzo Redondo, molecular virologist at the Feinberg School of Medicine at Northwestern University. The first dose helps prepare the immune system, while the second helps to improve it.
Photos of the Modern vaccine are being prepared in Garden City, New York.
Photographer: Johnny Milano / Bloomberg
“You can think of a paperback and a hardcover book. They are different on the outside, but they contain exactly the same information, “he says.” This genetic material, once introduced into our cells, causes them to produce identical viral proteins. Therefore, they are expected to generate the same response. immune ”.
The point, however, is that the dose mix of vaccines from different drug manufacturers has not yet been studied.
“There’s no data on that, so judgment needs to be made,” he says John Moore, vaccine researcher at Cornell University. “We would like to have data instead of using criteria. But we don’t have the luxury of data.”
In fact, just last week the U.S. Centers for Disease Control and Prevention was released updated guide reporting that in “exceptional situations” it is acceptable to administer a different vaccine at a minimum interval of 28 days between doses.
Moore says that if there was no alternative, he would not hesitate to mix the two vaccines. “We have to accept that we are in a somewhat abnormal situation right now,” he says.
Postdate: Barbara of Pitcairn, Pennsylvania, wrote with a follow-up question to last week’s newsletter. One reader had wondered if it was problematic if his second dose was delayed. Tony Moody, an infectious disease expert at Duke University, said he would probably be fine. “We know that the timing between vaccinations is closer to the minimum time between doses, not maximum,” he said.
Barbara’s dilemma, she wrote, is that she planned to make her second shot before the recommended three weeks for the Pfizer vaccine. “Is it okay to take it four days before the three-week recommendation?” she asked.
We followed up with Moody.
“Vaccine trials are generally run with time periods around each shot and the data is analyzed together,” he said. “So we don’t have a good way to know if 17 days versus 21 days really makes any difference.” There is simply no data to definitively answer Barbara’s question, Moody’s said. Still, he said, taking a second dose just a few days earlier should be fine.
“There should be nothing wrong with being a little early and it’s definitely better to be early than not at all,” he said. “I’m not sure it would drive much earlier than that.”
Thank you all for writing this week! Next Sunday we will answer the best question we receive again. So if you have any, we want to know. Write to us at [email protected] – Kristen V. Brown
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