South Africa may be entering fifth Covid wave earlier than expected
Rise in infections appears to be driven by Omicron sub-variants, say health officials
South Africans wait to be vaccinated at an ambulance converted into a mobile Covid-19 vaccination site in Cape Town. Photograph: Nardus Engelbrecht/AP
Reuters
Fri 29 Apr 2022 05.42 EDT
South Africa may be entering a fifth Covid wave earlier than expected after a sustained rise in infections over the past 14 days that seems to be driven by the BA.4 and BA.5 Omicron sub-variants, health officials and scientists have said.
The country that has recorded the most coronavirus cases and deaths on the African continent only exited a fourth wave around January and had predicted a fifth wave could start in May or June, early in the southern hemisphere winter.
The health minister, Joe Phaahla, told a briefing that although hospitalisations were increasing there was so far no dramatic change in admissions to intensive care units or deaths.He said at this stage health authorities had not been alerted to any new variant, other than changes to the dominant Omicron variant circulating.
The infectious disease specialist Richard Lessells told the same briefing that waning immunity from previous waves could be contributing to the earlier-than-expected resurgence in cases.
He said the rising share of infections attributed to the BA.4 and BA.5 sub-lineages of Omicron suggested they had a growth advantage over other Omicron sub-variants such as BA.2.
So far there was no sign that BA.4 and BA.5 were causing significantly more severe disease, said Waasila Jassat from the National Institute for Communicable Diseases.
South Africa has reported more than 3.7m Covid cases and more than 100,000 deaths during the pandemic. On Thursday, the WHO’s Africa office flagged the rise in South Africa’s infections as the main driver of an increase on the African continent.
Senior health official Nicholas Crisp also said on Friday South Africa had enough vaccine doses and was not planning to procure more. He added the government was not intending to buy Pfizer’s Covid treatment pill Paxlovid for public sector patients, partly because it was very expensive.
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New Omicron sub-lineages can dodge immunity from past infection
TIM COCKS
May 1, 2022, 11:35 AM
HAD BOOSTING ANTIBODIES AGAINST
ALL VARIANTS,
Scroll back up to restore default view.
By Tim Cocks
JOHANNESBURG (Reuters) - Two new sublineages of the Omicron coronavirus variant can dodge antibodies from earlier infection well enough to trigger a new wave, but are far less able to thrive in the blood of people vaccinated against COVID-19, South African scientists have found.
The scientists from multiple institutions were examining Omicron's BA.4 and BA.5 sublineages - which the World Health Organization last month added to its monitoring list. They took blood samples from 39 participants previously infected by Omicron when it first showed up at the end of last year.
Fifteen were vaccinated - eight with Pfizer's shot; seven with J&J's — while the other 24 were not.
"The vaccinated group showed about a 5-fold higher neutralisation capacity ... and should be better protected," said the study, a pre-print of which was released over the weekend.
In the unvaccinated samples, there was an almost eightfold decrease in antibody production when exposed to BA.4 and BA.5, compared with the original BA.1 Omicron lineage. Blood from the vaccinated people showed a threefold decrease.
South Africa may be entering a fifth COVID wave earlier than expected, officials and scientists said on Friday, blaming a sustained rise in infections that seems to be driven by the BA.4 and BA.5 Omicron sub-variants.
Only about 30% of South Africa's population of 60 million is fully vaccinated.
"Based on neutralisation escape, BA.4 and BA.5 have potential to result in a new infection wave," the study said.
(Editing by Frances Kerry) |
