Covid-19: Why "test, test, test" is easier said than done - BizHealthcare- 24 March 2020

Covid-19: Why "test, test, test" is easier said than done - BizHealthcare- 24 March 2020

BizHealthcare- 24 March 2020

BY: JAMES STENT & NATHAN GEFFEN
"Testing people suspected of Covid-19 and then tracing who they have had contact with is vital to controlling the epidemic. But the test for SARS-CoV-2, the virus that causes Covid-19, is both expensive and logistically time-consuming.
A complicated process

President Cyril Ramaphosa said on Sunday night that everyone returning back to South Africa from high-risk countries would get tested. This probably isn’t practical at the moment. Doctors we spoke to said the waiting time to get a swab taken from you at a private laboratory in Johannesburg was about half an hour and people had to be turned away at a state testing facility in Cape Town.

“It’s too much,” an infectious disease specialist told us. “We simply can’t test as much as South Korea.”

“I’d suggest that for now we test only people who are symptomatic and who have recent travel or contact with a confirmed case. That’s the National Institute for Communicable Diseases (NICD) recommendation. As the disease progresses, this may be loosened because we will assume everyone has had contact with an infected person.”

He emphasised that with limited resources, everything must be focused on sick people.

What’s in a test?

This is what’s involved in getting a test for the coronavirus that causes Covid-19:

First, a nurse or doctor takes a swab from you, preferably from your nose, which is usually the best place for getting the most virus. Swabs can also be taken from your pharynx, which can cause you to gag, or you can cough up sputum. If you watch videos of this being done, you’ll notice it’s not straightforward. The health worker taking the swab needs to wear a mask because of the possibility of you sneezing or coughing in his or her direction.

Then the swab needs to be taken to a lab quickly.

There a technician does what is called a polymerase chain reaction, or PCR, test on your swab. This test works by making copies of viral DNA till there’s enough to detect it. To do a PCR test you need a bunch of chemical reagents. For many infections, such as HIV, there are manufacturers around the world supplying kits with all the reagents the laboratory needs. But SARS-CoV-2 was only discovered a couple of months ago and as far as we can tell no such prepackaged commercial kit yet exists for it. So until such kits are available — which should be soon — laboratories have to source the various chemicals, using a protocol developed by the World Health Organisation.

Then the result has to be sent back to you. The result is also logged with the NICD. The process typically takes 24 to 48 hours but one laboratory doctor we spoke to on Monday said that with the massive increase in tests, the process will probably start taking longer as a backlog builds."

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