Rand Aid Association which runs four retirement villages in Johannesburg says 22 residents and employees have tested positive for Covid-19 at its homes.
It says of this, 18 cases are still active.
"Of the 18 active cases, 10 are residents and eight are staff members. Of these, many are asymptomatic and all are in isolation, with two in hospital.
"Three external service providers had tested positive and contact tracing was done to identify and test any staff members or residents who had come into contact with them," Rand Aid Association said in a statement.
Rand Aid Association runs Inyoni Creek, Elphin Lodge and Tarentaal in Lyndhurst and Thornhill Manor in Modderfontein.
It also runs two frail care centres for older persons - Ron Smith Care Centre, which is in the grounds of Elphin Lodge and Thembalami, which incorporates the Max Ordman Deaf Association in Lombardy East.
Collectively there are 1 400 residents and 425 employees at the care centres and retirement villages. When the nationwide lockdown was implemented in March, no visitors were allowed onto the properties, unless deemed essential.
Concerns were raised when two deaths of Thembalami residents were recorded - one in Rand Aid's isolation facility on 8 June and another in hospital on 6 June. Rand Aid Assocation said after tests were conducted for Covid-19 on all residents at Thembalami, it was revealed that everyone was negative except for two residents who were asymptomatic but tested positive for the virus.
The deaths of the two residents were not linked to the coronavirus.
"Despite the many precautions we have taken and put in place, we remain vulnerable to any person who unknowingly has the virus, as they may be asymptomatic. Also, as many of our residents have to visit hospitals and clinics and have various treatments and procedures from different healthcare providers from time to time, we had identified that the risk of infections was very real," Rand Aid CEO Peter Quinn said.
He added that the facilities are mindful that many of the residents have underlying conditions which make them vulnerable to the virus.
"We are tracking all coronavirus-related incidents within our villages on an ongoing basis to control the situation and react immediately when need be. Senior management and I also receive daily updates (or sooner, when an event is identified)," he said.
Dr Carmella Mielke, an expert in geriatric medicine who is based at Rand Aid's Elphin Lodge retirement village and who has been providing valuable assistance to Rand Aid, says Rand Aid's residents fall into the most vulnerable age groups.
"To quote the UN Secretary-General António Guterres, 'older people around the world are dying at a higher rate, and especially those over the age of 80 whose fatality rate is five times the global average'. The majority of our residents have underlying co-morbidities, frailty and poor functional reserve, all contributing to being extremely susceptible to the devastating outcomes of the coronavirus."