Things are really interesting just now as we start to get to grips with Omicron. And things are (possibly) looking far, far less bad than many had been thinking. So lets look first at the virology. Then at the epidemiology.
It looks like Omicron was first created when an immune compromised person in Africa (where there is a lot of AIDS) had HCoV-229E coronavirus (which causes the common cold) and SARS-CoV-2 (Covid-19) at the same time. This meeting of virus led to the 37 mutations (which are identical to HCoV-229E) of Covid-19 which define Omicron, all of which has been proven by genetic sequencing. The science is HERE. So perhaps Omicron can be considered to be a hybrid virus with mostly the characteristics of Covid but also partially the characteristics of the common cold. Which brings us to…………
A study by researchers at the LKS Faculty of Medicine at The University of Hong Kong found that Omicron infects and multiplies 70 times faster than the Delta variant and original SARS-CoV-2 in human bronchus. Which may well explain why it is so much more contagious. But that is not all. Omicron also replicated more than 10 times less efficiently in the human lung tissue. Which may well explain why its symptoms appear to be less severe. Science HERE.
So if we add these two pieces of research together we see that Omicron partially looks and behaves like the common cold. But it is still Covid-19.
Now to the epidemiology. It had been assumed from the early data that Omicon cases double every two days in a population. (This assumes a herd with no previous immunity, obviously any immunity will slow it down). It was thought that this would lead to a peak sometime between Christmas and New Year in the UK of about a million people a day being infected. After an incubation period of 7 to 10 days this would lead to a peak in new cases on about the 6th of January and a peak of deaths about three weeks later, around the 27th of January.
But now there is an alternate theory. That cases double every 1.5 days (once again assuming a herd with no previous immunity) but that it is being slowed down more than expected because previous exposure to the disease (largely by immunisation) is working far more effectively than expected. This theory actually fits the facts better than the 2 day theory because it explains the far lower and earlier peaks that South Africa is experiencing.
What would this mean? It would mean that Omicron has already peaked in the UK in terms of new infections and that we will very soon see a peak in new cases. That the peaks will be less than expected. That the disease will not be as severe as Delta. That the NHS is perfectly safe. That we don’t need any social restrictions. And that the booster programme has been a stunning success.
Of course this is just postulation, not proven science. But it is a viable alternative scenario. We shall see.