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The U.S. Food and Drug Administration is using a controversial strategy to evaluate the next generation of COVID-19 boosters.

The approach is stirring debate as the agency works to make new, hopefully improved, boosters available in September to help prevent severe disease and save lives in the fall and winter.

For the first time, the FDA is planning to base its decision about whether to authorize new boosters on studies involving mice instead of humans.

"For the FDA to rely on mouse data is just bizarre, in my opinion," says John Moore, an immunologist at Weill Cornell Medicine in New York. "Mouse data are not going to be predictive in any way of what you would see in humans."

But others defend the approach, arguing that the country has had enough experience with the vaccines at this point to be confident the shots are safe and that there's not enough time to wait for data from human studies.

"We have 500 people a day dying of coronavirus right now. Those numbers sadly might very well rise in the fall and the winter. The question is: 'Can we do something better?'" says Dr. Ofer Levy, a pediatrics and infectious disease researcher at Harvard Medical School who also advises the FDA. "And I think the answer is: 'We can, by implementing this approach.'"

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The mouse question is a sticky one. On one hand, if the FDA is going to demand clinical trials for every tweak of the vaccine, the virus will have changed enough by the time the vaccine is approved to make the effort untenable. We don't do this with the flu vaccine (which may not be a good argument but I don't know enough about it to say). On the other hand, mice are less like people than rats are in important ways, and pre-clinical studies with mice have failed (showed effect in mice, not in humans). I don't know why people insist on using mice, except that they are smaller than rats, eat less and have huge litters frequently. So they're cheaper.

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I'm OK, thanks. I went to a meeting in Liverpool and took a few extra days to visit Wales, do Beatles stuff, spend time with friends I hadn't seen in 3 years. Just what I needed. I was losing my mind with so much isolation. I've attached a few pics - the really scenic ones are from Wales.

In case you're wondering, I never stopped masking or taking other precautions such as eating outdoors, even though the UK has a very low rate of transmission now, partially due to its 91% vaccination rate. I did attend a banquet in a large room full of vaccinated people - that was my one risky behavior. However, the day after I returned I got a text from the (state) dept of health saying that my cell phone had been next to some infected person's cell phone for more than 15 min. That info could only have come from another American's cell phone. Two days later I tested positive for COVID. So, I'm pretty sure that my exposure came from someone on the plane, as we were all crammed together for 7 hours and I was the only one I saw wearing a mask, which I removed to eat. I went on antivirals, had flu-like symptoms for 3 days, and no longer tested positive a week after my first positive test (I had been testing myself everyday since my return, realizing that simply travelling was a risk factor.)

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In case you're wondering, I never stopped masking or taking other precautions such as eating outdoors, even though the UK has a very low rate of transmission now, partially due to its 91% vaccination rate. I did attend a banquet in a large room full of vaccinated people - that was my one risky behavior. However, the day after I returned I got a text from the (state) dept of health saying that my cell phone had been next to some infected person's cell phone for more than 15 min. That info could only have come from another American's cell phone. Two days later I tested positive for COVID. So, I'm pretty sure that my exposure came from someone on the plane, as we were all crammed together for 7 hours and I was the only one I saw wearing a mask, which I removed to eat.

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In the beginning, when the coronavirus was new, the quest for a vaccine was simple. Everyone started out susceptible to the virus. Shots brought spectacular protection.

But the next chapters of life with the virus — and the choice of booster shots for the fall and beyond — will be complicated by the layers of immunity that now ripple through the population, laid down by past infections and vaccinations.

When it comes to viral infections, past is prologue: The version of a virus to which we’re first exposed can dictate how we respond to later variants and, maybe, how well vaccines work.

It’s a phenomenon known by the forbidding name of original antigenic sin, and, in the case of the coronavirus, it prompts a constellation of questions. Are our immune systems stuck still revving up defenses against a version of the virus that has vanished? Will updated booster shots that are designed to thwart variants be much better than the original vaccine? How often will we be reinfected? Is there a better way to broaden immunity?

The answers to those questions will influence our long-term relationship with the coronavirus — and the health of millions of people. But more than two years into the pandemic, the quest to unravel these riddles underscores the seemingly unending complexity of the battle against a new pathogen.

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Originally posted by wtg:
Pretty interesting stuff about vaccines and immunity...reader mode works with WaPo articles, but if you can't get to it, let me know and I'll post it as a gift link.

It's longish but I think definitely worth reading.

quote:

In the beginning, when the coronavirus was new, the quest for a vaccine was simple. Everyone started out susceptible to the virus. Shots brought spectacular protection.

But the next chapters of life with the virus — and the choice of booster shots for the fall and beyond — will be complicated by the layers of immunity that now ripple through the population, laid down by past infections and vaccinations.

When it comes to viral infections, past is prologue: The version of a virus to which we’re first exposed can dictate how we respond to later variants and, maybe, how well vaccines work.

It’s a phenomenon known by the forbidding name of original antigenic sin, and, in the case of the coronavirus, it prompts a constellation of questions. Are our immune systems stuck still revving up defenses against a version of the virus that has vanished? Will updated booster shots that are designed to thwart variants be much better than the original vaccine? How often will we be reinfected? Is there a better way to broaden immunity?

The answers to those questions will influence our long-term relationship with the coronavirus — and the health of millions of people. But more than two years into the pandemic, the quest to unravel these riddles underscores the seemingly unending complexity of the battle against a new pathogen.

https://www.washingtonpost.com...e-response-boosters/