Covid-19 peak may be past, now let’s prevent a second wave

The focus of Covid-19 testing should now shift to monitoring community transmission, as this could detect asymptomatic infections which could assist in managing a possible second wave of the epidemic, experts say.

Despite South Africa having the biggest Covid-19 testing programme on the continent, the number of daily tests have dwindled in the recent weeks in conjunction with the dip in new confirmed infections.

As of 19 July 2020, private and public laboratories had conducted a total of 49,006 tests within rolling 24-hour periods, but this plummeted nearly a month later to 22,609 tests conducted in the 24 hours leading to Sunday, 16 August 2020.

The reasons for this was because testing was prioritising healthcare workers, essential service personnel, and hospital patients who were tested more frequently, said South African Medical Research Council (SAMRC) CEO Professor Glenda Gray.

“At the height of the epidemic, due to the global shortage of tests and reagents, the testing was reoriented to prioritise healthcare workers and people under investigation for Covid-19, and those admitted in hospital. We had to change the testing strategy so that we could focus on what was most important – and that was healthcare workers, essential services and hospital admissions,” she said.

This also included the elderly, people with comorbidities, and those who presented with Covid-19-related symptoms or were in contact with someone who tested positive, head of biometric sciences department at Cape Peninsula University Professor Glenda Davison said.

“The second reason [for the decline in testing] is that we have reached the peak, and so less people are presenting to hospital with severe symptoms requiring testing. So, the demand for testing has dropped.”

“There are probably many people who have had the infection and don’t even know they have had it. A large proportion of cases don’t have symptoms or have very mild symptoms and so the person may not even go to the doctor. The strategy of only testing at-risk individuals and those with symptoms will miss many who are infected,” she explained.

But now that the peak is declining, Gray suggests that the focus should go back to community spread and transmission, which could see more infections but could prevent and better manage a possible second wave.

“We are managing the epidemic from a hospital point of view and now we need to focus on trying to manage the transmission in the community and to go back to where we were in the beginning when we were doing community testing. That needs to start again as we try to manage and prevent a second wave.

“If we change our strategy, we would continue to see infections. They may be more asymptomatic infections but that is important because a lot of people out there are asymptomatic and may be transmitting without knowing. Even if we might see more infections, we might not see more hospital cases,” said Gray.

But what do 3.4 million tests mean?

As of Monday afternoon, private and public laboratories had conducted 3 400 638 Covid-19 tests, with 54% conducted by public laboratories.

This did not fully reflect the number of people tested as the figure includes those who might have tested more than once.

According to Davison, retesting could largely be due to employers insisting that a staff member first tests negative before returning to work. This was, in fact, a waste of testing as it was shown to be unnecessary, she said.

“A person is no longer infective after 14 days. Another reason is that if a test is done too early after initial infection (1 – 4 days), the result is often falsely negative. The best time to test is around day 6 – 8. In the beginning, we did not know as much about the virus as we know now and so often testing was done too early and then had to be repeated later.”

Healthcare workers and essential services personnel were also frequently tested as they were more vulnerable to infections and it was vital to know their status, Gray explained.

“People might test more than once if they get into contact with people. If we compare ourselves with other low middle-income countries, I think our number of tests done is comparable, if not better, to other low middle-income country settings.”

rorisangk@citizen.co.za

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