South Africa may be entering a fifth COVID-19 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 said on Friday.
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.
Health Minister Joe Phaahla told a briefing that although hospitalisations were picking up 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 one circulating, Omicron.
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.
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A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
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 like BA.2.
But 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 3.7 million COVID cases and over 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 uptick on the African continent.