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Viruses infect us more efficiently than we can test for them – why ‘Columbo’ Covid-questioning graphic is misleading

“Why is it necessary to search for the virus DEEP in the nose?” asks a graphic posted on Facebook in South Africa in May 2022. It’s clearly referring to Sars-Cov-2, the coronavirus that causes Covid.

The graphic adds: “Wouldn't it be sufficient to spit on the stick when the virus is supposed to be contagious within 6 feet?”

It shows a photo of US actor Peter Falk, fingers on forehead, in his role as the legendary TV detective Columbo. Columbo’s “gotcha” questions were always happily anticipated by viewers.

The graphic has been circulating on Facebook for at least a year. It can be seen here, here, here and here.

It’s been posted with comments like:

  • Sal van die antwoord hou? Waar is daai kamtige slim dokters? (Afrikaans for “Would you like the answer? Where are those so-called smart doctors?”)
  • Make it make cents !! #keepitrealamerica
  • Exactly WHY !! !!

But the graphic could cause harm. It leaves out important information about what viruses are, and why Covid testing is important.

The Sars-Cov-2 virus is far better at infecting us than we are at testing for its infection. There’s a big difference between how well the coronavirus invades our bodies and how well medical technology detects its presence.


Viruses are ancient – medical technology isn’t

Viruses are little more than genetic material – either DNA or RNA – that’s wrapped in protein and, sometimes, a layer of fatty material.

There’s a reason the word “virus” is also used for harmful computer code

A virus exists only to make copies of itself. It doesn’t eat or excrete, breathe, or reproduce as living things do. And it can only make its copies inside the cells of a living organism. The way these copies are made may damage or destroy cells, causing disease in the organism. There’s plenty of debate about whether viruses can be considered alive.

Viruses don’t have cells. But all the organisms that make up the five kingdoms of life do have cells – or a cell. The five kingdoms are animals (like insects, fish and people), plants, fungi (yeasts, mushrooms and more), as well the two kingdoms of organisms with only one cell: protozoa (“first animals” such as amoebas) and bacteria.

But viruses can invade the cells of creatures from all five kingdoms – animals and plants, and even fungi, protozoa and bacteria, organisms that can also cause disease. Malaria, for example, is a serious disease caused by plasmodium parasites. The parasites are part of the protozoa kingdom of life, and are as vulnerable to viruses as the rest of us.

Viruses have been copying themselves inside living things’ cells for billions of years, long before people existed. They’re really good at it. Our ability to detect them doesn’t compare.

Why Covid tests have to go deep

People’s knowledge of viruses goes back only a hundred or so years. And viruses are so tiny – just a packet of DNA or RNA, remember – that they can only be photographed by high-powered cameras designed to detect electrons, some of the smallest particles of matter.

Testing specifically for coronavirus infection is far more difficult for us than it is for the virus to infect us in the first place.

There are two types of Covid test. The RT-PCR test looks for the coronavirus’s genetic material. The antigen or antibody test looks for certain proteins that show an immune response to the virus.

Both tests are sensitive and need a good sample

For this reason, a 15-centimetre swab is inserted, yes, “DEEP in the nose” to collect fluid from the nasopharynx. The nasopharynx, at the back of the nasal cavity, connects the nose to the windpipe. It’s also a place Sars-Cov-2 makes many copies of itself, and a place easily reached. Fluids collected from the nasopharynx will, if the person is infected, have a good sample of the virus.

The 6 feet – or 2 metre – rule

Covid-19 is a serious disease that has killed more than 6 million people in just 52 months. More people in need of care have died because healthcare centres were overwhelmed by Covid cases.

Authorities across the world have established measures to control the disease. One is social distancing – that people in public places keep apart so that somebody with Covid is less likely to infect the people around them.

Covid-19 is spread mainly by aerosols. When an infected person talks, sneezes or coughs, they expel tiny drops of mucus containing the virus, which can infect people near them.

If you’re 2 metres – about 6 feet – away from an infected person, the aerosols have further to go and there’s a smaller chance of you getting Covid. Wearing a mask also helps.

Testing for Covid isn’t as easy as being infected by Covid. Covid tests need to be rigorous and reliable, not only to properly diagnose Covid patients but also to track the pandemic.

The graphic does ask reasonable questions. But it may also cause people to doubt established facts about how Covid is transmitted, and how people are tested for the disease.

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