Claim: Thermometers can detect Covid-19

Pic Source: Paul Adepoju/Nature Medicine
The Claim: Thermometers can detect Covid-19
The Verdict: claim verdict

Claim: ‘If I pass a thermometer screen test, it means I have no Covid-19’

Verdict: False

Apart from sanitising hands, most businesses and supermarkets rely on thermometers to conduct temperature checks as a way of screening individuals with high temperatures before entering their premises.

Most of the time, if not all, everyone is able to pass through the screening test because their temperature would be reading normal, causing people to assume they are safe from Covid-19.

But medical experts warn that thermometers are not 100 percent effective in detecting Covid-19, as they can only detect people who have a fever that is higher than normal body temperature.

“Thermometers cannot detect people who are infected with Covid-19, as most people who have coronavirus never experience symptoms such as high temperature,” said Dr Edwin Sibanda, Director of the Health Services Department in Bulawayo in an interview with CITE.

“Over 80 percent of people don’t develop symptoms that’s why thermometers can’t pick these and it may take the virus one to 14 days to incubate and cause symptoms like a fever, so a thermometer cannot be used to identify asymptomatic patients.”

Dr Edwin Sibanda

This has implications on entities or institutions, even gatherings that rely on this sort of screening to detect infections and prevent outbreaks.

Dr Sibanda stressed that is why physical distancing and washing hands was more important than relying on temperature checks.

“A thermometer can pick those likely to have symptoms but someone can have a simple cough without high temperature and there are many causes of fever. The bottom line is those who are not exhibiting symptoms are more likely to pass on Covid-19 than those who are showing symptoms,” said the health official.

“A thermometer does not pick everybody because out of people who have Covid-19 not more than 20 percent develop symptoms and out of that the percentage who develop high temperature ratio is less.”

A specialist community physician, Dr Nyasha Masuka noted that thermometers needed to be properly calibrated to reflect the real temperature of people.

“Fever is a common sign of Covid-19 but some people are asymptomatic. Obviously some people are moving around with Covid-19 and might never know they have it because they have never been sick therefore are not tested.”

Dr Nyasha Masuka

Anyone who is infected with Covid-19 could pass on the virus, regardless of whether they are experiencing symptoms or not, Dr Masuka pointed out. 

“The main way of passing Covid-19 is through droplets in the air – coughing, sneezing or talking. This means that even if you don’t have a cough, fever or other symptoms, you can still pass it on to people around you. That’s why wearing face masks was important in controlling the spread of the virus.”

Dr Masuka highlighted that taking someone’s temperature is not enough and though common, a fever was not the only symptom of Covid-19 meaning asking someone’s history was more ideal.

“That’s when you may need to ask the whole history of someone whether they were looking after someone with Covid-19 and other factors,” he said, however indicating that this was not feasible especially in a supermarket situation.

“People are fatigued now and are taking a lot of risks. That’s why we see crowding and it is very difficult to even screen properly.”

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