The herd immunity debates

Professors at University College London grabbed some headlines with the news that Britain’s almost achieved herd immunity.

Should we celebrate? 

Nope. The small print said we can’t ease restrictions yet. “If we let up, that threshold will go up again and we will find ourselves below the threshold and it will explode again,” Karl Friston said.

This makes it sound like we’ve probably misunderstood what herd immunity means. Or else that the people who wrote the study have. I thought it marked the point where we could all wander back to whatever we can reconstruct of our normal lives, trusting that the virus will stay in retreat. Apparently not, though–at least not by this definition. 

Irrelevant photo: a rose. Indoors. It’s too early in the year for them outdoors yet.

In a rare moment when the health secretary, Matt Hancock, and I agree (I’m sure that upsets him as much as it does me; sorry Matt; it won’t happen often), he’s dismissed the suggestion of herd immunity, although his comments are oblique enough to be unquotable. They’re not incoherent but they’re not exactly to the point either. Never mind, though. I have agreed with him. It’s a rare moment. We need to mark the occasion.

Cup of tea, anyone?

Another estimate of herd immunity, this one from Airfinity (it “provides real time life science intelligence as a subscription service” and as part of that tracks vaccination programs around the world), sets it at the point where 75% of the population is vaccinated. The U.K.’s expected to reach that point in August, shortly after the U.S. and a few weeks before Europe.

Sorry about the rest of the world. It seems to have dropped off the map the article I found was using. 

There will, of course, still be a need to booster vaccines to keep up with the variants, at least until those countries that fell off the map get access to vaccines so are species can stop producing variants so prolifically. 


Creeping out of lockdown

As Covid deaths go down, Britain’s taken another step toward ending its lockdown, opening gyms, shops, pubs and cafes with outdoor seating, assorted other businesses. Internal tourism is causing traffic jams in all the usual places. 

About half the population has at least one dose of a vaccine. Will that be enough to keep the virus from rebounding? I wish I knew. Chile has an impressive vaccination program and unlocked too early, giving the virus the gift of a trampoline. Cases there have spiked. 

Optimist that I am, my mind snags on Britain’s remaining virus hotspots and on the two London boroughs where the government’s chasing cases of the South African variant. I expect they’ll do better with the variant than with the hotspots, because one of the things the government resolutely refuses to do is pay people a workable amount of money to self-isolate, and if you’re broke you’ll go to work, regardless of what the test says. Because you have to. 

On the other hand–and before I go on I should issue an Unimportant Personal Story Warning–I’m grateful to have stores open. I have a battery-operated watch whose battery stopped operating a while ago. (Whose idea was it to run watches on batteries, anyway? I seem to remember winding my watch every day without feeling unduly burdened. I didn’t even break a sweat.) 

How long ago did the battery run out? No idea. We were in lockdown. Who needs a watch? But eventually I did need a watch and I noticed that mine was no longer in touch with consensual reality. So I got a battery (thanks, Tony). I opened up the back (thanks, Ellen), took out the old battery, put in the new one, put the innards back together, and was just starting to congratulate myself when I found that I couldn’t fit the back on, making the whole project pointless. I put a rubber band around the thing and left it alone.

I still didn’t have a watch.

On Monday, the first day that unimportant stores were open, I took it to a jeweler. Jewelers have a little gizmo to hold the back in place while they thump it shut. I now have a working watch.

I don’t need it more than once a week. We’re still halfway locked down. 

So yes, it’s nice to be able to do that sort of small thing. It also makes me nervous–and it should.


Lockdown and the economy

Britain’s economy’s now in the worst recession it’s had in 300 years. Worse than the Great Depression of the 1930s? Apparently. To find one that was worse, you have to go back to the great frost of 1709, when Britain was an agricultural country.

On the other hand, having shrunk 9.9%, the economy then grew by 1% in the last quarter of (I believe) 2020. Household savings during the pandemic reached £140 billion–16.3% of people’s disposable income. That’s compared to 6.8% in 2019. Predictably, that’s unevenly distributed, with some people building up savings while others struggle to hold onto their homes and food banks struggle to keep up with need. 

It’s a lovely way to organize a world. 


The Covid risk indoors and out

Want to figure out the Covid risk people face indoors? Measure the carbon dioxide level

This works because–well, the thing about infectious people is that they exhale. Admittedly, uninfected people do too. You probably do it yourself. And all that exhaled carbon dioxide joins together and either stays in the room or doesn’t. The Covid virus does exactly the same thing: It either stays in the room or if the room has enough ventilation it wanders out into the world, where it poses next to no danger.

The thing is that carbon dioxide levels can be monitored cheaply. If you see them rise, you still won’t know if anyone infectious is breathing into the mix, but you will know that the ventilation isn’t what it needs to be and it’s a risky place to stand around inhaling. At that point you can (a) limit yourself to exhaling, (b) leave, or (c) improve the ventilation. Preferably (b), since that will help everyone.


An Irish study reports that roughly one Covid case out of a thousand is caught out of doors. 

Professor Orla Hegarty said, “During Spanish flu people were advised to talk side by side, rather than face to face, and this is borne out by how viral particles have been measured moving in the air when people breath and speak.

“The risk of infection is low outdoors because unless you are up close to someone infected, most of the virus will likely be blown away and diluted in the breeze, like cigarette smoke.”

29 thoughts on “The herd immunity debates

    • Some months ago, I read that the problem with herd immunity for Covid is that we don’t know what percentage of the population it takes before we reach it. It’s different for every disease, depending on how it spreads. I’d wonder particularly about Israel having reached it because they have a concentrated population that’s refusing vaccination–ultra-Orthodox Jews. Because they’re a tight community, they could easily spread it to each other enough to kick up a resistant variant that could then break into the larger population. That is, I know, the pessimist’s view, but it’s worth some thought because it’s not impossible.

      That’s a variation on any country deciding it’s reached herd immunity until the planet does.

      Having said all that, I would so like to think this is over.

      Liked by 3 people

      • And Israel does not include Palestine in the statistics who have extremely low vaccine rates, around 2% and there is another wave starting with around 35% positivity rate. Look at the map of Israel and you can see how stupid this is. Palestinian lands are intertwined throughout Israel. I know this after spending four months there. Many Palestinians pass through borders for work on a daily basis. Israel has provided vaccines for these workers but not helped the general Palestinian population get vaccines which are in extremely short supply.

        Liked by 2 people

      • Yes, that’s the rub as I understand it, is 1) what’s the actual percentage number for herd immunity for COVID as it ranges from 65% to 90%+ for other diseases and we’re having to best guess it for now and 2) what’s the immunity percentage within your community? Since if it’s not evenly distributed across all areas, the group you need to care about is the one you associate with on a day to day basis.

        Unrelated: what a lovely rose! The bud formation reminds me a bit of a camellia, but the ruffle and delicate colors are a delight

        Liked by 1 person

        • I half agree about the group you associate with on a day to day basis being the one you need to care about. From day to day, yes, but from week to week or month to month, the boundaries are fluid. One person works in a supermarket, say, and it’s the summer so people are coming in from other parts of the country. Someone else in your group has kids in the local school, so you have to take all the other kids and their parents into account. Someone else–well, you get my point. We share the risk with everyone who everyone we know associates with, and it gets to be a large group very quickly. Which is what makes it personally scary that the South African variant has popped up in London, even though I live a five-hour drive from there. It’s spring. Lockdown has loosened and people are traveling. They could easily bring it with them.

          I’m glad you like the rose. I do too. It was given to us–one of those tiny potted things that may not last long (although I’m hoping) but that’s delicate and pretty while it lasts.

          Liked by 1 person

    • Good point. It depends how you count these things and how you define them.

      I’ve been struck with how much larger the Depression looms in American conversation than in British ones. I don’t know why that is–clearly it hit hard here as well.

      Liked by 1 person

        • Whew. That must’ve been horrifying.

          In the US, the Depression seems to have hit the middle class as well as the working class. They had more to fall back on, but I remember my mother saying about someone with an engineering degrees, “Engineers were a dime a dozen.”

          Liked by 1 person

  1. Nice round up of the numbers. I, too, am voting for caution with both my mouth & my feet. I have to tell you that I’m using you as one of the sources I find most reliable in the current circs.

    And the rose is especially gorgeous :)

    Liked by 1 person

  2. Another great round up. Herd immunity needs to be globalized, otherwise ….! As we easy out of lockdown, we all gather like crazies again. The old common sense and the fact it aint common . I am a bit fed up. And I side track now (deliberately), I am impressed by Johnson and Johnson ethics to pull back on their vaccine to make sure they get it right as it creates clots. I wish AZ – Oxford would do the same. Sorry I have been missing in action from reading your blog. life is upside down right now.

    Liked by 2 people

    • I’m no one to criticize other people’s reading habits. The irony of blogging to actively is that I don’t read many blogs. What can I say in my defense? Not much.

      It does sound like AstraZeneca got their communications completely wrong, from very early on. The risk, from what I’ve read, is small and I’m due for my second dose of it and have no hesitation about it. But yes, Johnson & Johnson does seem to have gotten it right.

      I do wish Britain wasn’t opening up so quickly. I live in a tourist area, and our local town is suddenly swamped with visitors. It’s worrying.

      Stay well.

      Liked by 2 people

  3. I had the Pfizer vaccine, but I can appreciate the caution and concern about the J & J – I probably would have taken it anyway, but though some experts are saying “The incidents are so few of the total cases !” – that doesn’t make the affected people any less sick or dead. Over here people seem relieved that we are getting some straightforward information, Staying careful is still the best option.

    Liked by 1 person

    • If staying careful is an option, yes, it’s a good one, but not everyone has the choice. I do agree that looking at the numbers and saying, “It’s a small risk,” sounds cold. One case is horrible if it’s you or someone you love. But we take a risk when we agree to have surgery. Or drive on the freeway. And somehow in spite of how awful the consequences can be, our minds don’t seem to have snagged on those stories and made us say, “Maybe we should put that on hold.” Because we need to do those things.

      I think we need to continue the vaccination programs as well. The risk of not doing it is too high. It really is.

      Liked by 1 person

  4. The vaccination feels like the last shot we have – no pun intended. If we do get ordered back into lockdown, compliance would be a huge challenge. Not speaking from a perspective of libertarianism, simply an observation.

    Liked by 1 person

    • Getting people to go into lockdown depends on two things: One is having food and enough money to live on. The other is trust that the government can handle the situation and that what you’re doing will help. Unfortunately, so many governments have blown it on both counts. I do worry that having gotten half a lid on this thing, the British government’s going to lose control once again.


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