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BA.2.75 subvariant not yet in SA, but mask mandate still an option: Phaahla

A World Health Organisation (WHO) official has confirmed that there is no new COVID-19 variant called ‘Centaurus’, but rather that social media has unofficially nicknamed the Omicron BA.2.75 sub-variant with this.

WHO Africa regional virologist Dr Nicksy Gumede-Moeletsi said it was incorrect for the media to refer to the variant as ‘Centaurus’, as the WHO had not given it this name and was not likely do so, reports IoL.

“The BA.2.75 is a sub-lineage of an existing variant that has already been named the Omicron variant. The name is not coming from the WHO, which is responsible for labelling variants, it's coming from people on social media,” she said.

The sub-variant was first detected in India last month and has since been found in more than 10 countries, including India, the United Kingdom, the United States, Australia, Germany and Canada.

Estelle Ellis and Aisha Abdool Karim write in Daily Maverick that BA.2.75 has been designated a “variant under monitoring” by the European Centre for Disease Prevention and Control (CDC). In addition to its rapid growth and geographical spread, virologists say it contains a high number of extra mutations.

It has not yet been detected  in South Africa, where, three weeks after the mask mandate was lifted, COVID cases have not shown a marked increase and surveillance programmes are showing similar case numbers to the flu.

In other parts of the world, including parts of the US, the UK and Singapore, significant outbreaks driven by the BA.2.75 and the BA.5 subvariants have been observed.

On 14 July, at a press conference, World Health Organisation director Tedros Ghebreyesus said subvariants of Omicron continue to drive global waves of cases, hospitalisation and death.

But he added that surveillance has reduced significantly, making it increasingly difficult to assess the impact of variants on transmission, disease characteristics and the effectiveness of countermeasures.

In South Africa, epidemiologists call this the “trough between waves”, with Health Minister Dr Joe Phaahla filing an affidavit in the Gauteng High Court (Pretoria), saying that the option to introduce a new mask mandate must remain an available public health measure in case of another outbreak.

The court is expected to hear an application by several organisations, including AfriForum and Sakeliga, to have interim regulations, which included the mask mandate – which has since been repealed – declared unconstitutional.

Phaahla repealed the rules on 22 June, but Piet le Roux from Sakeliga said their case highlights various concerns.

After President Cyril Ramaphosa lifted the State of Disaster, first introduced in March 2020, in April 2022 a set of interim regulations remained in place, including a mask mandate, until permanent regulations could be promulgated. The promulgation of these permanent regulations, which many claimed was the result of a flawed public participation process, was put on hold after Phaahla then extended the period for comment.

A set of interim regulations, including a mask mandate, was then put in place overnight. These regulations, among others, are the subject of the court battle involving Phaahla. On 23 June, he again, in a late-night notice published in the Government Gazette, repealed these regulations, but the litigation is continuing.

Should COVID still be notifiable?

One of the main points of contention is Phaahla’s argument that COVID-19 must be listed as a notifiable medical condition, making it compulsory to report to the National Institute for Communicable Diseases (NICD) if someone tests positive.

Le Roux said in an affidavit before court that they believe Phaahla is insisting on declaring COVID-19 a notifiable medical condition to give himself the option of being able to trigger strict regulations, providing him with similar powers to those of Minister of Co-operative Governance & Traditional Affairs Dr Nkosazana Dlamini Zuma under the State of Disaster that was declared in March 2020 and only lifted in April 2022.

In his affidavit before the High Court, Phaahla said a mask mandate must remain as a tool to fight a new outbreak of infections.

His main argument is the court should not hear the case, as he has withdrawn the matter, but he also dealt with allegations by the organisations that the regulations, which extended the mask mandate and further imposed some restrictions on gatherings and entry and exit into the country, were “irrational, unjustifiable or not supported by science”.

“The regulation requires the wearing of masks in indoor public places and public transport. The science is clear that there is a significantly higher risk of infection in enclosed congregate settings and that masks, even cloth masks, limit transmission. The fact that masks are less effective against a variant such as Omicron does not mean that it has no effect at all or that it will be effective against a future variant,” he said.

“While masking indoors may not become necessary during the troughs between waves and if COVID-19 becomes endemic, it is a public health measure that should be available in case of further waves,” he added.

The NICD’s latest sequencing report showed 29% of COVID-19 cases were caused by the Omicron variant BA.4 and 19% by BA.5.

In South Africa, where the two subvariants were identified as being the drivers behind an infection spike in May and June, the weekly incidence risk is also down. Gauteng has the highest numbers (an incidence risk of about six per 100,000) followed by the Western Cape (4.5 cases per 100,000 people).

Case increase have been reported only in the Free State and KwaZulu-Natal.

The number of people who are tested for COVID-19 symptoms is also down and the percentage of positive tests (about 5% to 6%) has remained largely unchanged.

“The immune landscape in South Africa is very complex,” said Dr Richard Lessells from the KwaZulu-Natal Research and Innovation Sequencing Platform, where Omicron was first identified. “Because we’ve had these five waves of infection and we’ve got vaccines, we’ve got this complex mix of immunity.”

Most South Africans have some kind of immunity to COVID by now. After two years and five waves, there have been almost 4m confirmed cases. But this only represents people who have been tested. The NICD estimates this is less than 10% of the actual number of infections in the country, meaning that more than two-thirds of the population could have some level of natural immunity to SARS-CoV-2.

Just more than half of South Africa’s adults have received at least one dose of a vaccine, according to the National Department of Health’s dashboard.

“In terms of South Africa and the kind of selection pressure for this virus now, any virus that’s going to gain an advantage in this context is going to be able to escape at least the immunity against infection,” Lessells said.

“For BA.4 and BA.5 to spread how they have, they had to have a property allowing them to gain an advantage in the population. And that property was that they were better at getting around the immunity in the population – particularly, they were a bit better at getting around the immunity that had been acquired from a BA.1 infection. That’s what allowed them to gain ground,” he added.

BA.4 and BA.5 were behind SA’s spike in infections during April and May that was classified as the fifth wave.

Lessells said although the subvariants BA.4 and BA.5 have stemmed from the original Omicron that was circulating in South Africa, they still behave like a different virus.

They are even trickier, as studies have shown that, even if you had one of the other variants or if you had the original Omicron variant, you can still be reinfected.

“We probably only pick up 10% of the infections, and, with Omicron, it’s probably even less,” said Lessells. He estimated that less than 5% of COVID cases during the last wave were actually picked up.

“That’s why we have this false understanding that reinfections are relatively rare, because diagnosed reinfections may still be relatively rare.

“But if we think about what we miss, then it’s clear that most of the infections happening now are reinfections.”

Aisha Abdool Karim writes for Spotlight.


IOL article – There’s no new Centaurus variant, says WHO official (Open access)


Daily Maverick article – Phaahla says mask mandate must remain a public health measure while world virologists express concern over scary Centaurus subvariant (Open access)


See more from MedicalBrief archives:


Continue wearing masks, government warns those at risk


Health Act amendments a bid by government ‘to cling to power’ – DA


Solidarity calls for health regulations withdrawal before court hearing


New BA.2.75 Omicron subvariant – and what we know so far


Moderna/Pfizer update two vaccines against newer variants




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