But symptoms such as fatigue are often not associated with myocarditis. And Dr. McManus suspects that the fatigue that sometimes follows an attack with Covid-19 could possibly be caused by this heart problem.
“We consider Covid-19 and influenza to be respiratory diseases, and in fact they are,” said Dr. Bruce M. McManus, a professor of emeritus pathology at the University of British Columbia, said. “But the reason many patients reach death in many cases is myocardial.”
Some seriously ill Covid patients have lung damage. It can also occur with other viruses, says Dr. Clemente Britto-Leon, a lung researcher at the Yale School of Medicine. He mentions some possibilities.
“You can have lung injuries and scars with flu, with herpes viruses and with cytomegalovirus infections, for example,” said Dr. Britto said and referred to a common virus that usually causes no symptoms. All of these viruses can cause damage in rare cases, he said. “You can be very seriously injured and destroy a lot of tissue.”
Influenza can cause blood clots in the lining of the lungs that look like the small blood clots seen in some Covid patients in the lungs, said Marco Goeijenbier of Erasmus University in the Netherlands. It happens when flu viruses infect the lower respiratory tract, an unusual occurrence because most people have a protective immunity.
Dr. Goeijenbier wants to study the blood clots that occur in these cases, but previously, with so few patients, he and others have turned to reproducing and studying the effect in laboratory studies and in ferrets.
“It was difficult to get funding,” he said. “Large magazines or funders did not find it interesting enough,” he explained.
Covid changes that.
There is now “a large group of people to study,” said Pamela Dalton, a Monell odor researcher. But ‘the big question is, even if you learn all about SARS-CoV-2’ – the formal name of the coronavirus – ‘how general is it?’