Durban - The third wave of Covid-19 is expected to hit the country by June.
While vaccines would be rolled out, experts believe that the fight against the pandemic is far from over.
Advisor to National Health Department the minister Zweli Mkhize, Aquina Thulare said a third resurgence in Covid-19 infections was inevitable.
“We have seen other countries in Europe, parts of Asia and the US experience third waves and we anticipate our own. Currently, the virus is unpredictable and there is much to be learnt but what is known is that the third wave and the issue of herd immunity are intertwined with the behaviour of the virus,” she said.
Thulare added that herd immunity would be achieved once about 40 million citizens were vaccinated and this would take about a year.
“Until then we need to continue non-pharmaceutical protection measures like mask-wearing, social distancing, hand washing and sanitising.”
Professor Salim Abdool Karim, co-chairperson of the Covid-19 ministerial advisory committee and director of the Centre for the AIDS Programme of Research in South Africa, said the third wave would hit between June and July.
“We survived the second wave which is officially over as we have nationally crossed the threshold of low transmissions but we will continue to see about 2000 new cases per day. Drawing from experience and information gathered throughout the onset of Covid-19 in the country, we know a third wave will occur and it will hit in about three to four months which is around June and July. But between May and June we expect to discover new variants, and the greatest fear is that the new variants would mutate to bypass immunisation which would undermine all our efforts and the third wave would be devastating,” Karim said.
He said the roll-out of vaccines would have little impact in preventing or mitigating the effects of the third wave.
Professor Tulio de Oliviera, bioinformatician and director of the KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), said the virus was learning and mutating to survive.
“There are three main variants and they were discovered in South Africa, the UK and initially in Japan which was later linked to Brazil and all three present multiple mutations. We do not know what is driving the emergence of new variants.
“One hypothesis is that these mutations developed in immune-compromised individuals like patients undergoing long-term cancer therapy who couldn’t adequately attack the virus when it was developing. Two patients have been followed over time and they have seen very similar mutations appearing, one was in Boston, US and covered in the New England Journal of Medicine and the other patient was in Cambridge, UK.
“The N501Y mutation is common across all three variants and is associated with increased transmissibility as well as the 484K mutation that allows the virus to escape vaccine neutralisation.
“In the last few weeks, a second hypothesis came about that variants emerge from areas severely affected by previous waves as those who were infected would have increasing antibody levels so when the new virus arrives it is not enough and would need to develop antibody escaping mutations. We do not know which hypothesis is correct,” De Oliviera said.
Richard Lessells, KRISP’s Group Leader and infectious diseases specialist, said the hurdle was that vaccines would always be steps behind the virus.
“The virus is constantly evolving in new ways to spread especially while vaccines are rolled out which is why controlling transmissions is crucial. We would begin to see new variants emerge to combat the immune responses triggered by vaccines but the vaccine is not evolving.
“Next-generation vaccines would be required that can target a wider range of Covid variants that could address the constant evolution of the virus,” said Lessells.