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Source: https://news.yahoo.com/scientists-serious-mixing-matching-covid-140044585.html
Scientists get serious about mixing and matching COVID-19 vaccines
Melissa Healy
Sat, February 27, 2021, 9:00 AM?8 min read
A lot of us have engaged in some bold mixing-and-matching during the pandemic — office attire on top, pajama pants on bottom, for instance — and been none the worse for it.
Imagine doing the same with COVID-19 vaccines, perhaps pairing a first dose of the AstraZeneca product with a second dose supplied by Novavax. Will the consequences of such mixing be any graver?
It’s hardly an idle question. Either by accident or design, some mismatched dosing is inevitable, experts say.
Two vaccines are currently being rolled out across the United States, with a third expected to join them next week and two more likely to come over the next several months. All but one were designed to be delivered as two-dose regimens.
An additional 69 vaccines are in clinical development across the globe, and nearly two-thirds of those were designed to generate immunity with two or more doses.
But making sure people get the right vaccine at the right time has turned out to be a greater logistical challenge than initially expected. What's more, the unexpectedly swift emergence of menacing coronavirus variants has made it imperative to get shots into arms as quickly as possible.
Health officials in Britain proposed a radical solution to both problems: Delay second doses for up to 12 weeks so that more people could get at least some protection. Later, the government acknowledged that in exceptional circumstances, mismatched doses may be given to people who arrive for their second dose and discover that the vaccine they originally had is not available.
It seemed preposterous, especially considering that neither of these protocols was evaluated in clinical trials. If they don't work, the precious vaccine will have been wasted at a time when there's none to spare.
“I wouldn’t make any changes unless you’ve got good data,” said Dr. Anthony Fauci, director the U.S. National Institute of Allergy and Infectious Diseases. “I don’t think you mix and match without results showing it's very effective and safe.”
Now British researchers are trying to do just that.
This month, a team of vaccinologists from Oxford University began recruiting 800 or so people age 50 or older for a complex study to see whether vaccine switching could actually work.
Using an eight-armed clinical trial, they'll test vaccine regimens using various combinations and intervals of the two vaccines currently being dispensed in Britain: one made by Pfizer and BioNTech, and another developed by Oxford and AstraZeneca.
In announcing the mix-and-match vaccine trial, Dr. Matthew Snape cited experiments in mice in which combinations of the Pfizer and AstraZeneca vaccines boosted immunity better than two doses of either one alone. Perhaps it would work in humans as well....
Scientists get serious about mixing and matching COVID-19 vaccines
Melissa Healy
Sat, February 27, 2021, 9:00 AM?8 min read
A lot of us have engaged in some bold mixing-and-matching during the pandemic — office attire on top, pajama pants on bottom, for instance — and been none the worse for it.
Imagine doing the same with COVID-19 vaccines, perhaps pairing a first dose of the AstraZeneca product with a second dose supplied by Novavax. Will the consequences of such mixing be any graver?
It’s hardly an idle question. Either by accident or design, some mismatched dosing is inevitable, experts say.
Two vaccines are currently being rolled out across the United States, with a third expected to join them next week and two more likely to come over the next several months. All but one were designed to be delivered as two-dose regimens.
An additional 69 vaccines are in clinical development across the globe, and nearly two-thirds of those were designed to generate immunity with two or more doses.
But making sure people get the right vaccine at the right time has turned out to be a greater logistical challenge than initially expected. What's more, the unexpectedly swift emergence of menacing coronavirus variants has made it imperative to get shots into arms as quickly as possible.
Health officials in Britain proposed a radical solution to both problems: Delay second doses for up to 12 weeks so that more people could get at least some protection. Later, the government acknowledged that in exceptional circumstances, mismatched doses may be given to people who arrive for their second dose and discover that the vaccine they originally had is not available.
It seemed preposterous, especially considering that neither of these protocols was evaluated in clinical trials. If they don't work, the precious vaccine will have been wasted at a time when there's none to spare.
“I wouldn’t make any changes unless you’ve got good data,” said Dr. Anthony Fauci, director the U.S. National Institute of Allergy and Infectious Diseases. “I don’t think you mix and match without results showing it's very effective and safe.”
Now British researchers are trying to do just that.
This month, a team of vaccinologists from Oxford University began recruiting 800 or so people age 50 or older for a complex study to see whether vaccine switching could actually work.
Using an eight-armed clinical trial, they'll test vaccine regimens using various combinations and intervals of the two vaccines currently being dispensed in Britain: one made by Pfizer and BioNTech, and another developed by Oxford and AstraZeneca.
In announcing the mix-and-match vaccine trial, Dr. Matthew Snape cited experiments in mice in which combinations of the Pfizer and AstraZeneca vaccines boosted immunity better than two doses of either one alone. Perhaps it would work in humans as well....