Friday, May 24, 2024

Covid-19 vaccine rollout faces double-barreled problem

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Andrew Noymer, medical demographer and associate professor of population health and disease prevention at the University of California, Irvine, who criticized the plan from Biden officials on Twitter“Adds:” We are in the situation we are in now because everything that could go wrong has gone wrong – with testing, contact tracing, etc. The idea that we’ll fix everything in three weeks, when those second doses come in, is a fantasy. It’s playing with fire.

The conversation about changing Covid-19 vaccination schedules started with the UK government, which ad on December 30, he will extend the interval between vaccinations from three or four weeks to 12 weeks. (Britain uses the Pfizer vaccine, as well as a formula from the University of Oxford and AstraZeneca that has a four-week interval. This vaccine has not yet been approved in the United States.) change was intended to enable as many Britons as possible. develop some degree of protection against newly discovered, and more transmissible, B.1.1.7 variant the virus, which was first detected in the UK before Christmas and has now spread around the world, including in the USA.

Days after the British announcement, government officials in Denmark and Germany ad they can also expand their vaccination campaigns. Simultaneously, two prominent medical academics offers in The Washington Post that the United States should also extend their dosing intervals. And around the same time, the Chief Science Advisor for Operation Warp Speed offers a different strategy on CBS Face the nation: maintenance of the Moderna vaccine dosage regimen, but reduction of the dose by half.

Nothing has changed in the United States yet, although the HHS announcement on Tuesday means states will adjust their plans; in fact, Azar encouraged states to act quickly by promising that those who run out their doses quickly will be the first to get more. But the simmering disagreement and unease didn’t subside either.

“When you interrupt a vaccination program by saying: Look, we’ll get to the second dose when we can, there will be a lot of people who don’t get that second dose, ”says Paul Offit, pediatrician and vaccine developer at the Children’s Hospital of Pennsylvania. “We know that from the shingles vaccine, which is given and then given again two to six months later, and only 75% of people come back for the second dose.”

This second dose is crucial for achieving immunity because vaccine formulas work according to a strategy of invoking an immune response with the first dose and then strengthening it with the second. The first dose confers some protection: more than 50% for the Pfizer formula, more than 80% for the Moderna formula. But their clinical trials weren’t designed to detect, and didn’t report, what happens to that first immune response if the second hit is delayed.

For those who recommend distributing the first dose as widely as possible, and thus possibly delaying a second, achieving less protection in more people appears to be an acceptable compromise. “We do not offer do not to give the second dose, and we are certainly not proposing to delay it for several months, ”says Ashish K. Jha, physician and dean of Brown University School of Public Health, co-author of Washington post editorial which recommended expanding the dosage to the United States. “But we think there’s no good scientific reason to believe that if you delay a few weeks the protection will somehow decrease – whereas not having 50% of Freezer doses would have such a profound impact on reducing hospitalizations and consumption. of ICU beds.

Read all of our coronavirus coverage here.

Both increasing the dosage and reducing the dose aim to achieve the same result, ensuring that the available vaccines are given to the maximum number of people. It is a response to perceived scarcity. But it contains a contradiction – because at the moment vaccines are not uncommon. Yes, fewer doses were delivered than the companies and Operation Warp Speed ​​promised. But two-thirds of what was delivered is not used. Almost every day there are reports of hospitals throw out expired doses and pharmacies offer the stroke to anyone nearby during closing time.


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