Reading between the lines - Chris Witty implies Omicron will be more severe due to lack of natural immunity

On Wednesday evening, another Omicron press conference was held at Downing Street.  In response to a journalist’s (Tom Newton Dunn) question about severity and mortality, Chris Witty (England’s Chief Medical Officer) discussed initial findings from South Africa and whether we can use them to predict what will happen in the UK.

I have transcribed his response below.

There are broadly two ways that a virus like this could be less severe if someone’s caught it.  One of which is it’s intrinsically less severe, it’s just a milder virus….but the other way, in which is much more common actually, where something becomes more severe (sic) is because we have more immunity and the point I was making in South Africa, they, between the last wave and this wave, their degree of immunity has substantially increased and therefore there is much greater South African immunity to COVID in general, not specific to Omicron, than there was in the last wave so some decrease in severity you would expect because of some protection from increasing immunity.  In contrast for our Delta wave we already had incredibly good immunity due to the amazing job the NHS has done in double vaccinating everybody so we don’t have that additional thing on top so it may be that some of, possibly even all of any decreased severity from South Africa is just explained by immunity and if that’s the case that’s not something you necessarily replicate here.

Let’s deconstruct what he is saying here. 

Firstly, he says that you would expect a decrease in severity because of some protection from increasing immunity.  Makes sense, the more immunity there is, the less severe the virus will be for those people. 

The reason given for the increase in immunity (and therefore decrease in severity) is that between the Delta wave and this wave, South African’s immunity has substantially increased.   What immunity are we talking about here and where has it come from?  A lot of South Africans have been vaccinated since the Delta wave but only 26% of the population in total compared with 70% in the UK.  So, if it were vaccination immunity decreasing severity then it should apply in the UK and even more so.  However, Chris Whitty goes on to say that any decreased severity in South Africa from immunity, is not something you necessarily replicate here [in the UK].

So if it isn’t the immunity from vaccinations decreasing severity it must be natural immunity.  He is very careful not to say it but that is the only conclusion.  He says the South Africans have immunity to COVID in general, not specific to Omicron.  Here he is saying that (as many studies have shown and people pointed out) natural infection provides a broader immunity, as opposed to the specific original protein spike immunity (which is not even circulating any more) provided through the current vaccines.

He goes on to say that for our Delta wave we had incredibly good immunity due to the NHS double vaccinating everybody but we don’t have that additional thing on top.  That additional thing on top is the broad immunity provided through natural infection (or traditional vaccines).  So, he is saying here, that the vaccines dealt with the Delta wave well enough (debatable, but for another post) but they did not provide us with a broad immunity and so it is likely that Omicron will be more severe than in South Africa.

Having gone through the Delta wave and the beginning of the Omicron wave, South Africa’s deaths per 1 million population is currently 1,494 whilst the UK’s is 2,146.  Some of this can be explained by age due to South Africa’s median age being 27.6 with the UK’s at 40.5.  However, if when adjusted, the death rates are similar but South Africa has achieved a broader immunity, resulting in Omicron being less severe, the UK has failed with its risk analysis and resulting policies.

Reading between the lines, Chris Whitty said in his quote above, that Omicron may be less severe in South Africa due to their natural immunity and the UK’s vaccinated immunity is unlikely to be as resilient.  Many of us have warned about this from the beginning.  If South Africa have a broader immunity going forwards and with a similar age-adjusted death rate, then the UK should not have vaccinated anybody at low risk of COVID.  If Omicron turns out to be more severe in the UK, then it is a clear policy failure and people and institutions must be held accountable.  Furthermore, (and more worryingly), there is a strong possibility that the UK will lurch from crisis to crisis whilst South Africa doesn’t.  New vaccines for current variants will be produced but the same issue will arise over time.  Polyvalent vaccines may alleviate this worry but it is still unknown whether Original Antigenic Sin will prevent currently vaccinated individuals from ever gaining a broad immunity, restricting them to immunity only against the original spike protein.