As third wave looms, new variants throw predictions awry

‘First Covid-19 vaccines unlikely to be impactful’

The detection of two new variants to our shores has shaken the foundation of the latest modelling on Covid-19 in SA.

In the case of the latest “third wave” estimates, released by the SA Covid-19 Modelling Consortium last week, it was emphasised that none of the five scenarios they generated included the presence of a new variant.

They cautioned, however, that “the emergence of a highly transmissible new variant may result in a third wave of the same size as the second wave or worse, especially if the variant provides an opportunity for immune escape”.

Less than a week later, and just before the official vaccine rollout on May 17, we’re staring at a reality that does include new variants – though it isn’t clear how dangerous these will prove to be.

It was announced on Saturday evening that 11 cases of the B.1.1.7 variant – first discovered in the UK – had been detected in the Western Cape, KZN and Gauteng, while four cases of the B.1.617.2 variant found in India were also detected in Gauteng and KZN.

Yesterday, health minister Dr Zweli Mkhize said on eNCA: “Once someone comes with a variant from any part of the world, the risk is that their immediate contacts will be exposed and then community transmission can follow.”

He said this was why contact tracing and appropriate isolation measures were being “intensified in all cases”.

“We must work on the basis that any of these variants can spread and any work we do is about trying to limit the spread. The threat is as bad as the variant we already have in SA.”

He said that we have seen the “huge harm” that can ensue when a new variant arrives and that “the risk is that any variant can behave in a manner we can’t predict”.

This comes when early signs of a third wave have appeared, and the vaccine rollout – according to experts – is unlikely to make a dent in that.

Wits University virology expert Prof Shabir Madhi said: “As signs of a third wave are already emerging, it is unlikely we will get sufficient numbers of high-risk individuals vaccinated before the wave is fully established.”

Furthermore, “we are only targeting a limited number of people”, and “the first generation of Covid-19 vaccines are unlikely to be that impactful against infectiousness and mild infection”, which means

“we will still see large numbers of cases documented”.

On the upside, the number of hospitalisations and deaths in the third wave could be influenced by the vaccine rollout, and this “depends on the percentage of high-risk individuals who get vaccinated, and the timing thereof in relation to the wave”.

According to Prof Barry Schoub, who leads the ministerial advisory committee on vaccines, the variant from India should not be cause for major alarm. He said “convalescent blood [blood in people infected previously]” seems to neutralise the variant detected in India “quite well”.