'A worrying increase in cases': Covid-19 third wave looms

It’s a race against time, but experts say that vaccines — due to be rolled out more broadly from May 17 — are unlikely to save SA from a Covid third wave.

Professor Wolfgang Preiser, a virologist at Stellenbosch University, told the Sunday Times the challenge was the pace of the rollout, which will initially target people over 60. 

“It is basically too slow to make an impact if the third wave strikes during the next few months, as some people fear. On a population-wide basis, not enough people will have been vaccinated to make a dent into the next wave.”

However, “as so many South Africans have been infected during the first two waves, many of them will have some degree of immunity and that will hopefully reduce the extent of the third wave”, Preiser said.

He cautioned, though, that immunity resulting from previous infection is of unknown duration and “that nobody should rely on it” or ditch ventilation, masks, hand hygiene and social distancing.

Wits University vaccinology expert Professor Shabir Madhi said much is riding on “how quickly we get people vaccinated, and when the third wave arrives”.

“As signs of a third wave are already emerging, it is unlikely we will get sufficient numbers of high-risk individuals vaccinated before the wave is fully established.”

Furthermore, the rollout next week would target a limited number of people and “the first generation of Covid-19 vaccines are unlikely to be that impactful against infectiousness and mild infection”.

This meant many new cases would be reported, Madhi said. 

But the number of hospitalisations and deaths in the third wave could be held in check, depending “on the percentage of high-risk individuals who get vaccinated, and the timing thereof in relation to the wave”.

Earlier this week, the South African Covid-19 Modelling Consortium released data on five possible scenarios for a third wave.

The researchers left vaccines out of the picture, and based the scenarios on the degree to which people adhere to nonpharmaceutical interventions, as well as the extent to which the government imposes restrictions.

The scenarios ranged from 7,800 deaths if the response is “fast and strong” to 70,000 deaths in the case of a “slow, weak response”. 

The third wave would likely cause fewer infections than the second wave, but a “slow, weak behavioural response would increase admissions for severe or critical cases across most groups”, the consortium said.

Preiser said it would help that many health-care workers had already been vaccinated.

“So many of them are now vaccinated that we should see fewer getting infected during the next wave, which will be very valuable to keep the health system running,” he said.

Staff off sick, or in quarantine, is a major issue during outbreaks as it reduces the capacity to respond to the surge in cases.”

Preiser said figures were being monitored very closely to “recognise the build-up of the third wave as quickly as possible”.

Small infection clusters are also being investigated quickly, and wastewater is being tested regularly, he said. Minister of health Zweli Mkhize said this week that over the past fortnight “a worrying increase in cases” had been noted, particularly in North West, Gauteng, the Free State and the Northern Cape. This week, for the first time since mid-February, new daily infections began rising by about 2,000 a day. 

Dr Muzzammil Ismail, a public health expert at the University of Cape Town, said the public should actively monitor signs of a third wave.

He and the team behind the Western Cape Covid dashboard have updated it to include a user-friendly “resurgence monitor”, which allows users to keep abreast of whether new infections indicate the start of a third wave.

“We see the public as partners in the outbreak response,” Ismail said.

“Every person, every industry, every business, must be able to answer the question of whether we are entering the third wave, and the faster we are aware of this, the more time we all have to plan, prepare and adjust our behaviour to limit the impact on our family, friends, colleagues and community.”