I am seeing a lot of anxiety around partial immunity through vaccination producing selection for escape variants. Here @colinrussell and I explain why we *don't* think that's likely 1/n science.sciencemag.org/content/372/65…
It depends on the supply of the mutations that enable immune evasion. If we assume this happens during breakthrough cases in vaccinated people, there's not much time for it to make a difference, because transmission tends to happen early on in infection 2/n
And if breakthrough cases are less likely to transmit in general (as seems so in at least some cases) that makes it even more difficult 3/n papers.ssrn.com/sol3/papers.cf…
Selection is certainly a really powerful force, but it gets a helping hand from 'standing variation' meaning diversity in the population in vulnerability to the selective pressure before it is introduced - in its absence, they don't get selected. But that can change 4/n
What leads to a lot of diversity in the viral population? A lot of infections! And what is the best way to reduce infections? Vaccination! (aided and abetted by non-pharmaceutical interventions natch) 5/n
I can see some questions about infections in immunocompromised individuals. I think we need to watch these extremely carefully. Not clear to me that less immunity will provide more selection, but our experience so far should lead to vigilance 7/n
And of course the best way to stop infections in the immunocompromised is to stop the virus before it can get to them! And vaccination will help with that too 8/n
Now there is still a lot of infection, but there are a lot of vaccines too (and vaccinated people). We are continuing to learn more about them including how they work against variants. That will be something to watch closely in the coming months 9/n
But for now we should remember we are in a MUCH better place than we were, that every day brings us closer to the end, and that our attention should turn to those parts of the world still struggling to get people vaccinated 10/end
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The UK is going to be making free rapid tests available to everyone. As you might imagine, I approve. However it should be remembered rapid tests are most effective when combined with other things. Short thread 1/n nytimes.com/2021/04/05/wor…
For a start, for tests to be useful they have to be used! It is not obvious to me that there is any incentive for that in the proposal. If people suspect they are infected, but don't want the risk of having to isolate, they're not likely to take a test 2/n
Then there's the perennial question of what happens in the event of a +ve test? If people actually isolate that's great, but that's not been universally the case in the pandemic so far, putting it mildly. Hopefully their behavior would change enough to make a difference 3/n
Getting immunity from a vaccine is vastly safer than from infection, both as an individual because it avoids the negative consequences of infection AND for the community because unlike the virus, these vaccines don’t transmit
So I am quite pleased that a decent fraction of Fla residents have received at least one shot, the more the merrier
I predicted a few months ago that Fla would be quieter than other places over the winter because of larger number of contacts outside. I don’t know if that *was* the reason but the relative quietness did materialize even as variants have grown to a large proportion of cases
Reading this, which looks like a pretty definitive take on the origins of the pandemic. Important conclusion: most zoonoses of this kind would go extinct of their own accord. science.sciencemag.org/content/early/…
That actually makes a lot of sense if you consider everything we know about the clustered nature of transmission. Like they say, we should do better at detecting zoonoses early on
Nice illustration of how a transmission chain could sputter along a bit before making it big. Note that what this means is that while the pandemic descends from the market in Wuhan, that's not necessarily where the index case occurred
Absolutely right. The various aspects of the failure need more thorough unpacking in a medium that is probably not twitter, but it is actually striking to me how *much* we (meaning epidemiologists) knew a year ago about what this virus is capable of, and how little it has changed
Just as a for instance, the varying severity by age has been known pretty much since Jan 2020. And so has the potential for presymptomatic transmission, which is absolutely essential to the effort needed for control, and the importance of rapid testing
I was very aware of the potential for minimally symptomatic transmission because of my involvement in this (true story - I wrote my draft on an overnight flight at the end of feb. Then we all got slammed and it wasn't submitted for months) ncbi.nlm.nih.gov/pmc/articles/P…
There are a lot of think pieces going around about the pandemic one year on. This is one of the best, from @jameshamblin, because it is upfront about the difficulties we face handling uncertainty. That's relevant to then, and now. A short 🧵commenting on the issues raised
The first thing to remember is that uncertainty about precise numbers is not an excuse to avoid action. This is a common misunderstanding about how mathematical modeling results should be interpreted. Depending on your inputs, you can get all sorts of results...
The goal is not to forecast exact outcomes, because you hope you never experience the world in which nobody intervenes *at all*, but to understand how seriously to take the threat. Qualitatively right is not the same as exactly quantitatively right.
A long sobering look at the pandemic in the UK. The success of the vaccine rollout should not obscure the way that leaders failed to heed the lessons of spring 2020 to an extent that beggars belief nytimes.com/interactive/20…
Look at the cumulative deaths. Around 40k in spring of last year. In other words ~2/3rds of the total are from the last few months (data from worldometers.info/coronavirus/co…)
While some of this is down to the emergence of B.1.1.7, it is mostly down to an attitude that resisted taking appropriate action, and ignored scientific advice. As many will know, I think 'led by the science' isn't the right way round - we should be led by those we elect. But...