Covid-19 antibodies as high as 68% in latest Western Cape study

Dave Chambers Cape Town bureau chief
A nurse at the Khayelitsha District Hospital in Cape Town gets her Covid vaccine jab. File picture.
A nurse at the Khayelitsha District Hospital in Cape Town gets her Covid vaccine jab. File picture.
Image: Esa Alexander

More than two-thirds of diabetics in the Western Cape's biggest township have Covid-19 antibodies, the provincial government said on Thursday.

Leftover blood from routine tests in February was tested for antibodies and showed that poorer, densely populated areas such as Khayelitsha (68%) and its neighbouring townships have the highest antibody levels, said health department head Dr Keith Cloete.

The lowest antibody levels were in the province's more affluent and rural areas, which meant people there would be most at risk from the third wave of the local outbreak, said Cloete.

Speaking during premier Alan Winde's weekly Covid-19 media conference, Cloete said only 20 health workers in the province have active cases of Covid-19 and this may be an early sign of the impact of the Sisonke vaccination programme.

So far, 36,000 Western Cape health workers have been injected with the Johnson & Johnson vaccine as part of the Sisonke implementation study being carried out nationally.

The 20 active patients — four doctors, four nurses, a pharmacist and 11 others — are among 8,851 Western Cape health workers who have had Covid-19 in the past year.

The provincial Covid-19 dashboard reported on Thursday that active cases are down to 2,188 from a high of almost 44,000 in mid-January, and Cloete said all key indicators were heading downwards.

No Covid-19 deaths were reported on Wednesday for the first time since October and the test positivity rate has fallen to just 5.1%. In Khayelitsha, the infection rate has fallen to 6/100,000 people.

The number of wastewater treatment stations at which no traces of Covid-19 were found in sewage was 18, double the number a week earlier.

However, Cloete and Winde both sounded warnings about the danger of Easter gatherings turning into superspreader events that could fuel the third wave of Covid-19.

Winde pleaded with people to stick to the Covid-19 rules over the holiday. “We need to push out the third wave as far as possible into the year,” he said.

The antibody survey, which tested blood from diabetics, HIV-positive people and children in the middle two weeks of February, found seroprevalence averaging as high as 47% among diabetics in the Cape Town metro, and 60% among those with HIV.

Diabetic patients cared for in the private sector had seroprevalence of only 28%, however, and overall seroprevalence in the more affluent southern suburbs was 38%.

The 30-59 age group had the highest seroprevalence, while those above 60 — and especially people over 75 — had the lowest, which Cloete said “supports the notion that we should start vaccinations with the elderly”.

Planning for the mass rollout of vaccinations is targeting a May start, and Cloete said vaccination sites of five sizes would each be capable of administering between 100 and 2,000 jabs daily. 

The province is persisting with efforts to secure its own supply of vaccines, and has made 28 inquiries. However, no positive responses have been received yet and Cloete said the target date for securing the first vaccinations was August.

Health MEC Nomafrench Mbombo called for urgent clarity from the national health department on details of the vaccine rollout.

After visiting women farmworkers in Stellenbosch on Thursday, she said: “The only question I get anywhere I go is, when are we going to get the vaccines?”