No time for Covid-19 complacency – the pandemic is not over, experts say

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  • SA may already be in the fifth Covid wave, so experts are urging people to get vaccinated and boosted.
  • Two new Omicron sub-lineages, BA.4 and BA.5, are behind an increasing number of Covid cases.
  • Vaccination offers better protection against infection caused by these sub-lineages than immunity from prior infection.

South Africa may have already entered the fifth Covid-19 wave ahead of winter, and two experts agree that to avoid a surge in Covid-19 hospitalisations, people should ensure they’re vaccinated and boosted.

Last week, Health Minister Joe Phaahla warned that Covid-19 remained a threat and that SA couldn’t afford to drop all prevention measures.

He said: “It's going to be a very long winter where people spend more time indoors, where gatherings will largely be indoors, with a risk of high spread of any respiratory infections.”

Phaahla added that it would be an incorrect public health approach to believe that because there were high levels of immunity among South Africans, mostly induced through prior infection, the virus should be allowed to spread. 

“We don’t believe this is the correct approach because it will put a serious pressure on our health facilities and health workers,” he said, adding: “We urge those who are not vaccinated to come forward and take the jab. We know that natural immunity wanes with time and … [immunity] can only be boosted through vaccination.”

As of 4 May, fewer than 40% of adults aged 18–34 years had been vaccinated.

Ongoing need for precautions

“I understand how people could become complacent with respect to Covid but we are not nearly finished with the epidemic,” Professor Landon Myer, director and head of the School of Public Health & Family Medicine at the University of Cape Town (UCT), told Health24. 

He added: “We are certainly seeing ongoing transmission as we go into winter and with it, preventable hospitalisations and deaths in our families, friends and communities.”

Myer said that everyone needs to remain vigilant to prevent new infections and reduce the impact of infection. “And the best way to do this is to make sure your vaccinations are up to date – including recent boosting – and that we continue to take personal precautions like mask-wearing, hand-washing, and making sure our shared spaces are well ventilated,” he said.

‘This appears to be the fifth wave’

Another expert agreed on the importance of people getting vaccinated and getting their booster dose.

“The Covid pandemic is not over and we are seeing cases and hospitalisations going up. There are also indications that deaths are on the up. This appears to be the fifth wave,” said Professor Thomas Scriba, who directs the clinical immunology laboratory at the South African Tuberculosis Vaccine Initiative, UCT.

The risk of Covid-related severe disease and death has decreased significantly, due to a large portion of the population having some level of immunity from natural infection and/or vaccination, but there are still many who are at risk of the severe effects of the disease. 

Scriba explained: “There is clear evidence from multiple well-conducted studies that vaccine boosters provide high-level protection against Covid and that the benefits of these boosters far outweigh any risks of vaccination.”

Omicron sub-lineages: latest research

Scriba also referenced the recent findings of research conducted by Dr Alex Sigal, a virologist at the African Health Research Institute in Durban, and his colleagues.

The researchers measured immunity against the Omicron BA.4 and BA.5 sub-lineages by people infected with the original BA.1 Omicron sub-lineage, which, along with BA.2, dominated infections in SA’s fourth wave. The two new sub-lineages, however, are responsible for an increasing number of infections in the country, Health24 reported last week.

Scriba explained: “Dr Alex Sigal’s team … [found that] the current BA.4 and BA.5 viruses, which are causing this 5th wave, are escaping immunity from the prior BA.1 Omicron infection (fourth wave in SA), but that antibody neutralisation of the viruses in vaccinated people is about five-fold higher than unvaccinated people.

“In other words, there is clear evidence that vaccination is providing protection against Covid caused by these new BA.4 and BA.5 viruses over and above the immunity from prior infection.”

The study, which has been submitted to the preprint medRxiv, tested immunity in unvaccinated people infected with BA.1, and in people previously vaccinated with the Pfizer or Johnson & Johnson vaccine and who had breakthrough BA.1 infection. A breakthrough infection occurs when a fully vaccinated person gets infected with Covid.

In a tweet posted on 29 April, Sigal commented on the results: “My guess based on this: BA.4/BA.5 escape, while not as dramatic as Omicron escape from vaccine or Delta immunity, is enough to cause trouble and lead to an infection wave.”

However, he believed it was unlikely to cause much more severe disease than the fourth wave, especially in people who were vaccinated.

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