The total number of people in the UK who died with or from the coronavirus may never be known due to the lack of testing and the numbers self-isolating alone without medical supervision, a coroner has warned.

Speaking to BuzzFeed News on the condition of anonymity, the coroner said that, with tests currently “rarer than hen’s teeth”, it would be much harder to establish where COVID-19 was responsible in cases where untested people die at home alone and are not discovered for some time.

“There will be people who don't see or speak to anyone and those deaths may not get picked up, not least because they could well be quite decomposed by the time they are found,” the coroner said.

The uncertainty around deaths was underlined by the chief coroner for England and Wales who issued new guidance warning that it may not be possible to carry out some postmortems during the crisis.

The Office for National Statistics also issued guidance to doctors last week enabling them to report COVID-19 as a cause of death on the death certificate if they believe it to be the case, whether because a test, symptoms, or other clinical factors indicate this. “In the circumstances of there being no swab [test] it is satisfactory to apply clinical judgement,” the ONS said.



But, the coroner told BuzzFeed News, it “boils down to whether people report symptoms to their doctor or anyone else.”

If a patient had not been tested or received medical care, giving the doctor little indication of what caused their death, further investigations could be triggered.

But a leading pathologist, Dr Mike Osborn, chair of the death investigations committee of the Royal College of Pathologists, told BuzzFeed News that while a coronavirus test performed on living patients can be used on the deceased, it could be harder to rely on until more is known about the disease.

“The tests are designed and verified for living people as you would expect,” he said. “So, [with] the use in the deceased you'd have to be careful how you interpreted the result. I'm not saying that you can't use it, but it's been developed for living people. So whilst it may be a useful test, you can't necessarily interpret as much from it or use it as extensively as you might do in the living.”

After all deaths, changes occur in the body, he said, “and that makes interpretation of results harder and not necessarily directly correlated to what you would interpret those results to mean in the living”.

The longer a person is dead before being tested, the harder it could be to establish whether they had coronavirus, because “after somebody dies, the virus would denature over a period of time”, Osborn said.

The speed of this would vary according to a number of factors, but in general, “the more virus you've got, the more likely you are to be able to pick it up”, he said.

“As the viral load decreases over time, the likelihood of the test being positive or the results being as reliable — or it being as easy to interpret the results — probably decreases.” He stressed that more work would need to be done on those who have died to understand the picture better.

But currently, he said, the number of postmortems being carried out on people with COVID-19 was "vanishingly small” — he'd only done one so far for a research case “to get tissue to our scientists around the country … to investigate the disease further, learn from it to better model it, and develop treatments for it”.