Lockdowns again

There is a renewed discussion about the upsides and downsides of lockdowns in controlling COVID-19, and the alternative of protecting the vulnerable.

I stand by what I said in my The Conversation article:

(…) lockdowns can be seen as a failure of other, more gradual public health policies. A lockdown should be seen as an efficient but also very blunt public health tool, to be used in necessity but as part of a wider strategy.

https://theconversation.com/did-the-covid-lockdowns-work-heres-what-we-know-two-years-on-176623

But – in (another, slight) change of heart, I accept @pieterstreicher argument that the initial lockdown should have been followed by a critical evaluation and switch to other containment strategies.

Mark W has from the beginning advocated a “shielding” strategy of protecting the vulnerable; a strategy that I think would have been unworkable and disastrous if applied on its own.

The problem is that we saw lockdowns as the only solution. They gave us time and we used it to develop vaccines.

But we miserably failed to use the time to strengthen the health system. This is why the next waves were so devastating.

So, what do I think about the 2020 strategy:

  • at the time in 2020 we did not have many options to stop/slow down the epidemic;
  • the lockdown had to be applied and should have been applied much earlier;
  • it did work by giving us time;
  • we did not use the time very well.

Hindsight is a great thing, but I believe that with what we knew about the disease then, any other strategy would have led to a collapse of NHS and massive deaths.

What should we have done later – after the initial lockdown? Implement a combined strategy (some form of lockdowns, masks, quick development of treatment) instead of lurching from one extreme to another.

In our 2012 paper, https://link.springer.com/article/10.1186/1471-2458-12-679… we showed that the “middle ground” strategy is the worst solution. Instead, if the epidemic can be stopped, it should be stopped by the strongest measure available. If not, we should apply “soft” management.

Polio 2022

Recall that polio spreads mostly through the faecal route, i.e. through contaminated water. Preventable by vaccination and (almost) eradicated by mass vaccination campaigns:

Still present in some countries in the world:

but “endemic” in only a few countries although largely declining as vaccination cover and hygiene improve:

Hopefully only few cases in London.

Monkeypox: update on June 22nd, 2022

UK data: red and black points: UKHSA data, blue points: OWD data (shifted by 11 days), solid line: model

What a difference a couple of days make! When on Monday I was finishing the analysis underlying my new The Conversation article, I was expecting the monkeypox epidemic to start fizzling off. Indeed, the Our World in Data records were showing a flattening of the disease progress on Monday and Tuesday.

Then, yesterday (June 21st, 2022) brought a bombshell of a 38% increase in the new cases reported in the UK. Does this increase change my analysis?

I am going to stick to Scenario 3 which I think represents best the current situation. In that scenario, there is a core group sized N among whom the virus is spreading. In addition, there is an exchange of members of that group with the larger population by which the individuals who are immune move out of the group and are replaced with new individuals who are susceptible.

I believe this captures the current dynamics best, with the core group largely composed of Men who have Sex with Men (MSM) with some spillover to the general population but without a substantial community spread.

The current key parameters are N=1200 (a slight increase from the original piece of N=1000), \beta=0.59 (a slight decrease from \beta=0.6) and d=1/60 (same as before, meaning one person swapping on average every 2 months).

The model still seems to work, although the most recent jump is underestimated. It remains to be seen what happens in the next few days and weeks. I am still quite optimistic and think that with vaccination we might move back to Scenario 1 and finish the epidemic shortly. However, it is not inconceivable that we might move to an endemic situation.

@ConversationUK