Omicron revisited

I am afraid the current Omicron predictions [£] are quite scary:

Let’s parse it a bit:

Both England and Scotland have currently high levels of Delta. Even though this strain will possibly be replaced by Omicron, it still creates a huge pressure on the health service.

Omicron keeps growing – from 7% to 15% in a week in Scotland – and it seems like the numbers are doubling every three days. Let’s put it in context.

How serious Omicron is?

The reproductive number, R, for Delta under the current conditions (vaccination, masks, social distancing) is about 1 (and it has been like this for months). Without restrictions and vaccination, Alpha was believed to have R_0=4.5 and Delta R_0=6.

For Omicron to have a doubling time of 3 days means R of about 3, similar to the original strain without any restrictions.

This means that with restrictions Omicron spreads three times faster than Delta; hence, without any restrictions and vaccines, it would have had R_0=18, similar to measles.

There is no chance current vaccination will stop it from spreading; herd immunity remains an even less attainable dream.

Indeed, there is evidence that vaccine efficacy for spread is lower for Omicron than for Delta, following two vaccines (of course it must be, as Omicron is spreading).

The levels of cross-immunity due to the previous infection with Alpha or Delta, months after the big wave, is also quite small. We will need to gain immunity to Omicron, either by vaccination – the third dose, improperly called “boosters” seems to be working – or by re-infection.

Public health officials are rightly concerned. Even if Omicron has a lower hospitalisation rate, the sheer numbers might overwhelm NHS. The biggest problem now, of course, is whether we, the public, are likely to respect the regulations.

What next?

Everybody is tired; we – rightly so – have enough of masks, social distancing, intrusion of the government into our private life.

Multiple times we were promised that if we made the last effort (do not travel, do not visit, do not sing, get the vaccine), the epidemic will end and we will be “free” again.

I have always been a very strong proponent of the strategy of “making the last effort”. But I am no longer. I hate to say it, but I am getting more and more of the opinion that we need a radical change to the strategy.

I am not sure what it should be, but I am certain that it must be built on trust between the public health officials and the public itself. Do we have enough of it to prepare ourselves for a long time with the virus?

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