The Covid virus has a Darwinian quality. As variants emerge, they compete with one another to become dominant. The most contagious variants tend to win the competition because they can spread more quickly. It’s survival of the fittest. That is why the virus has become more contagious over time. Today,Continue Reading

Many measures of adolescent mental health began to deteriorate sometime around 2009. It is true of the number of U.S. high-school students who say they feel persistently sad or hopeless. It’s also true of reported loneliness. And it is true of emergency room visits for self-harm among Americans ages 10Continue Reading

As the pandemic enters its third year, long Covid has emerged as an increasingly important concern. And many people are wondering whether getting a Covid shot can reduce their chances of developing long-term symptoms. What does the research show so far? The jury is still out, but a growing numberContinue Reading

The left-right divide over Covid-19 — with blue America taking the virus more seriously than red America — has never been the pandemic’s only political divide. Each partisan tribe has also had its internal disagreements. Republicans have long been split over vaccination, with many eagerly getting shots while many othersContinue Reading

Few of Covid-19’s peculiarities have piqued as much interest as anosmia, the abrupt loss of smell that has become a well-known hallmark of the disease. Covid patients lose this sense even without a stuffy nose; the loss can make food taste like cardboard and coffee smell noxious, occasionally persisting afterContinue Reading

Good morning. We’re covering escalating tensions in Ukraine, arrests in the Canadian trucker protest and the fate of Afghan government funds. Fears of Russian invasion mount Diplomacy is stalling and U.S. officials believe an invasion could begin at any time. Here are live updates. On Sunday, airlines suspended flights overContinue Reading

Over time, Ms. Purvis, the speech-language pathologist, incrementally ramped up the exercises: arrange numbers in descending order, repeat a sentence in reverse. She increased noise and distraction to approximate Ms. Lewis’s busy work environment. She kept the door open, turned on television news and eventually held sessions in the bustlingContinue Reading