With Covid raging in India and Brazil, it’s a strange time to be talking about herd immunity, but a cluster of scientific articles are doing just that.
How many people need to be immune to a disease in order for the population as a whole to be protected? The answer varies with the disease. For measles, which is very contagious, the estimate is 95%. Vaccinate that many (or wait till they get sick and grow their own immunity) and the other 5% will get protection simply from not being around anyone covered with itchy little spots.
For the initial Covid strain, the best guess was that herd immunity would come when 70% of the population was immune. But as a planet, we handled the disease so badly that we’re not dealing with that strain anymore. Instead, we have a small raft of more contagious strains, so the bar we have to jump over before we reach herd immunity has probably gone from–oh, let’s say waist height to shoulder height.
Oh, yes, lucky us.
Irrelevant photo: Wood anemones.
So far, the countries with widespread vaccination programs also have groups of people who refuse to be vaccinated–that’s in addition to some who for medical reasons can’t be. They also have groups who for social and political reasons haven’t been reached. The US and UK haven’t done as well at vaccinating ethnic minority groups as they have at vaccinating whites. When I last checked, in April, Israel had gotten only dribbles of vaccine to the occupied territories, saying they weren’t its problem.
And most importantly, the world at large has done a shit job of getting vaccine to the poorer countries. So all those pools of unvaccinated people are where the disease will spread and mutate and create new variants, each of which carries in its itty bitty little pockets the possibility of outrunning the vaccines that those of us who are vaccinated are so relieved to have.
Israel has vaccinated just upwards of 60% of its population and has in large part returned to normal life, but that normality depends on keeping its borders largely closed and wearing masks indoors. Countries like New Zealand and Australia, which have in large part stamped out the virus, rely on tight border control and strict quarantine. How long they can or have the will to keep those barriers in place remains to be seen.
One article (the link’s above) says that the trick will be keeping restrictions in place once case and hospitalization numbers drop. Primarily, it says, these will be Covid tests and masks.
And just so’s you know: There’s no agreed-upon definition of herd immunity. I’m going to skip the details and say only that this doesn’t make the conversation about it any clearer. For a sensible discussion, go here.
Some of the articles I’ve read say we’re unlikely to ever completely eliminate Covid. In countries that have been heavily (but not completely) vaccinated, it’s likely to continue circulating and causing deaths, but at dramatically lower rates.
Sorry. It’s not the knock-out punch we were all hoping for, but it’s a hell of a lot better than the alternative.
Dr. Anthony Fauci tells us not to worry about herd immunity.
“People were getting confused and thinking you’re never going to get the infections down until you reach this mystical level of herd immunity, whatever that number is.
“That’s why we stopped using herd immunity in the classic sense. I’m saying: Forget that for a second. You vaccinate enough people, the infections are going to go down.”
The search for a Covid pill
At least three of the big drug companies are working on pills to keep mild Covid from turning into severe Covid. If they succeed, they’d make Covid’s continued presence in our lives a hell of a lot more manageable.
The first days after the virus moves into a human host are its busiest. It sets up housekeeping in a cell and creates a family to admire its work. And then the family spreads out, setting up housekeeping in new cells. And so forth. It multiplies like mad, and that’s when we’d need to drop that little pill–you know: the one that doesn’t quite exist yet–down our throats to disrupt the sequence.
Researchers have trolled through existing drugs, hoping to find one that would, by chance, do the job but so far haven’t come up with anything. Hence the search for new ones.
One that’s in development is a protease inhibitor, which would interfere with the enzymes the virus needs to multiply. (No, don’t ask me. I’m just playing parrot here.) Drugs that treat AIDS and hepatitis C are protease inhibitors, in case that gives you the same illusion of understanding that glowed so nicely in my brain until I realizes I didn’t really understand a thing.
Other drugs in development target the virus itself. That does’t glow quite as nicely and I’d love to say more about the process but that’s all I’ve got, although I can repeat that they’d disrupt the virus’s ability to replicate itself.
The companies are hoping to have the first of the drugs on the market by the end of the year. And they may end up being used in combination to keep the virus from evolving some form of resistance.
Don’t give up, folks. We’ll get through this, even if life isn’t quite the same as it used to be.
It wasn’t perfect then either, was it?
Notes from the U.K. 