In the Northern Hemisphere, we are heading into Winter, and because I just booked my appointment for COVID-19 and flu shots, I thought it would be useful to update people on where we now stand with respect to the pandemic — and yes, it is actually still that.
If you don’t want to read the details of this newsletter, ChatGPT has summarised it for you.
For those who want the details … read on.
Immunity Evolution
The big thing is that for most people now, the coronavirus is no longer novel. Pretty much everyone has had experience with it, if not by vaccines, but through exposure and an immune response. That is a big deal as it now puts the coronavirus on a par with all the other coronaviruses out there, as well as other respiratory illnesses. In other words, hospital surges, etc are very unlikely, but those with weaker immune systems still face risks.
But that fact actually changes our attitudes towards getting exposed. I still see a few people who wear masks but for many people, our risk calculus is a little different. Exposure can help. Here is an interview with Michael Mina from an immunology perspective:
When you say “hundreds of times,” that’s striking. The way most people think about a virus like, say, R.S.V. or chickenpox, is that a single exposure, while potentially worrisome, does deliver lifelong protection. Is it really the case that, as babies, we are fighting off those viruses hundreds of times?
The short answer is yeah. We start seeing viruses when we’re 2 months old, when we’re a month old. And a lot of these viruses we’ve seen literally tens, if not hundreds of times for some people by the time we’re adults. People tend to think that immunity is binary — you’re either immune or you’re not. That couldn’t be farther from the truth. It’s a gradient, and your protection gets stronger the more times you see a virus.
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With Covid, when it infects you, it can land in your upper respiratory tract and just start replicating right there. Immediately, it’s present and replicating in your lungs and in your nose. And that alone elicits enough of an immune response to cause us to feel really crappy and even cause us to feel disease. But it’s why we don’t see the severe disease as much, with a second exposure or an exposure after vaccination: For most people, it’s not getting into the heart and the liver and stuff nearly as easily. But it doesn’t have to. It’s still causing symptomatic disease. And maybe mucosal vaccines could stop this, but without them we’re likely to continue seeing infections and even symptomatic infections.
This is a very different story about immunity than we were told through most of 2020 and into 2021, though. Back then, I think the conventional wisdom was that a single exposure — through infection or vaccination — would be the end of the pandemic for you. If this is basic virology and immunology, how did we get that so wrong?
The short answer is that epidemiologists are not immunologists and immunologists are not virologists and virologists are not epidemiologists. And, in general, physicians don’t know anything about the details. And the world has never before been forced to so directly grapple with these nuances.
In other words, getting exposed a lot seems to be part of the point. My interpretation here is that keeping yourself fully masked up and protected may make it harder for your immune system to fight Covid should you get it. This is just me reading what the immunologists seem to be telling us. For me, that has made me completely relaxed about exposure, and I do little now to protect myself. But for everyone, there has been a change in the risk calculus, and you may want to recalibrate your behaviour.
Vaccine effectiveness
Vaccines are a tricky issue. I’m old enough now that it seems like getting vaccinated as much as possible is a good idea. I do other things, too, like taking copious amounts of Vitamin D.
But the Covid vaccines target the “latest” variant, by which I mean the “latest variant they have had a chance to develop a vaccine for.” So there is a lag.
As Eric Topol notes, the current vaccines are targeting a variant and a branch that is not where the virus is going. The virus is kind of going old school.
As I’ve stressed innumerable times previously, we need better vaccines (nasal and pan-coronavirus) to ante up vs the relentless evolution of the virus—its ability, now under population immunity pressure, to keep finding news ways to evade our immune response, enhance transmissibility, and achieve more (re-)infections.
In the meantime, if you haven’t gotten a booster, it would be a very good idea to go ahead. That’s especially important if you are of older age or are immunocompromised. In the U.S. they are approved for all age groups 6 months and older, and there would be some protective benefit across the board, but as with any intervention, a bigger bang for those at highest risk. Even if our current booster does not evoke a strong neutralizing antibody response to JN.1 (or subsequent BA.2.86 descendants), it will rev up our immune system, including cellular immunity, for conferring enhanced protection. As always, non-pharmacologic means of preventing infections help work against all strains of this and other respiratory viruses that are out there now (including flu and RSV).
Even if it turns out that JN.1 is not particularly deleterious, the main message here is that concerning variants keep cropping up and there’s a new path for the virus to find its way—versions that are getting further away from where this all started nearly 4 years ago.
The emphasis is mine. I never quite know what to make of statements like that but it is consistent with the “keep the immune system working out” notion that I talked about above. The other part of me worries it is some form of wishful thinking. But for me, I’ll be proactive on vaccines at my age.
Rapid tests
Long-time readers know that I love me some rapid tests. But things have changed largely because the coronavirus is not novel. This means that when we are exposed, our immune system kicks right in, and we get a symptomatic response. With symptoms comes information. That means that a rapid test is not an advanced warning of infectiousness. The symptoms are that. Instead, the rapid test can help you work out whether you are safe to be around others as the symptoms abate.
Here is Mara Aspinall.
Negative rapid test on Day 1 of symptoms doesn’t mean what it used to
One of the main reasons why COVID became a pandemic was the virus’s ability to be spread by people who were infected but didn’t yet have symptoms. By the time people did break with symptoms, they were at their peak viral load - and highly likely to test positive on a rapid antigen test. According to a recent article in Clinical Infectious Diseases, that’s no longer the case.
Between April 2022 and April 2023, the researchers looked at viral load relative to symptom onset in 348 COVID-positive, symptomatic patients. Median SARS-CoV-2 viral loads didn’t peak until the fourth or fifth day of symptoms. Based on Ct counts, the researchers estimated that “rapid antigen test sensitivity was 30.0% to 60.0% on the first day, 59.2% to 74.8% on the third, and 80.0% to 93.3% on the fourth.”
Commentary: There’s good news and bad news here. On the one hand, this (admittedly small) study suggests that rapid antigen tests aren’t as useful as they once were for diagnosing an infection in its early stages. However, it also suggests that asymptomatic spread may not be the issue it once was. That said, people need to act responsibly when they first have symptoms - by masking in public places or (when possible) just staying home - until they’re sure they don’t have COVID. Otherwise, we’ve just traded one problem for another.
This makes sense. It also makes sense to keep some rapid tests on hand if you are visiting those with weaker immunity systems.