Early in the Covid-19 pandemic, researchers found preliminary evidence suggesting that people’s blood type might be an important risk factor — both for being infected by the virus and for falling dangerously ill.

But over the past few months, after looking at thousands of additional patients with Covid-19, scientists are reporting a much weaker link to blood type.

Two studies — one at the Massachusetts General Hospital and the other at Columbia Presbyterian Hospital in New York — did not find that Type A blood increases the odds that people will be infected with Covid-19.

Continue reading “Covid-19 Risk Doesn’t Depend (Much) on Blood Type, New Studies Find” →

A stretch of DNA linked to Covid-19 was passed down from Neanderthals 60,000 years ago, according to a new study.

Scientists don’t yet know why this particular segment increases the risk of severe illness from the coronavirus. But the new findings, which were posted online on Friday and have not yet been published in a scientific journal, show how some clues to modern health stem from ancient history.

“This interbreeding effect that happened 60,000 years ago is still having an impact today,” said Joshua Akey, a geneticist at Princeton University who was not involved in the new study.

Continue reading “DNA Inherited From Neanderthals May Increase Risk of Covid-19” →

Following a birthday party in Texas on May 30, one man reportedly infected 17 members of his family with the coronavirus.

Reading reports like these, you might think of the virus as a wildfire, instantly setting off epidemics wherever it goes. But other reports tell another story altogether.

In Italy, for example, scientists looked at stored samples of wastewater for the earliest trace of the virus. Last week they reported that the virus was in Turin and Milan as early as Dec. 18. But two months would pass before northern Italy’s hospitals began filling with victims of Covid-19. So those December viruses seem to have petered out.

Continue reading “Most People With Coronavirus Won’t Spread It. Why Do a Few Infect Many?” →

In a study not yet published in a journal, scientists have reported that the new coronavirus was present in wastewater in Barcelona, Spain in March 2019, a finding that, if confirmed, would show that the pathogen had emerged much earlier than previously thought.

But independent experts who reviewed the findings said they doubted the claim. The study was flawed, they said, and other lines of evidence strongly suggest the virus emerged in China late last year.

Up until now, the earliest evidence of the virus anywhere in the world has been from December 2019 in China and it was only known to have hit mainland Spain in February 2020.

Continue reading “Study Suggests Coronavirus Emerged Much Earlier Than Thought. Some Are Skeptical.” →