Cases of hepatitis of unknown origin, first detected in UK children, have now been recorded in four more European countries and the U.S., the EU health agency said on Tuesday.

Pfizer and BioNTech on Thursday announced positive results from a clinical trial on the safety and immune response of a third dose of their Covid vaccine in children aged five through 11, adding they would soon seek regulatory authorization.

What do we know about "stealth omicron" so far?

It's an extra-contagious version of the omicron variant, but it doesn't seem to cause more severe disease.

Some residents of Shanghai were allowed out of their homes as the city of 25 million eased a two-week-old shutdown Tuesday after videos posted online showed what was said to be people who ran out of food breaking into a supermarket and shouting appeals for help.

About 6.6 million people will be allowed to leave their homes, but some must stay in their own neighborhoods, according to the online news outlet The Paper. The government said some markets and pharmacies also would reopen.

Novak Djokovic is ready to move on from the controversy surrounding his refusal to get vaccinated against COVID-19.

"I miss competition," the Serbian tennis star said Sunday on the opening day of the clay-court season at the Monte Carlo Masters in Monaco. "I still feel motivation to be on the tour and compete… and try to challenge the best players in the world for the biggest titles."

Following a public uproar, Shanghai is allowing at least some parents to stay with children infected with COVID-19, making an exception to a policy of isolating anyone who tests positive.

The announcement came as China's largest city remained in lockdown and conducted more mass testing Wednesday following another jump in new cases.

Real Madrid will likely be without coach Carlo Ancelotti for the first leg of the Champions League quarterfinals against Chelsea because of COVID-19.

Ancelotti tested positive for the coronavirus last week and did not travel to London with the rest of the squad on Tuesday.

Patrice Abela first knew something was wrong when his eldest daughter was learning to walk and her feet left trails of blood behind her, yet she showed no sign of distress.

She was soon diagnosed with congenital insensitivity to pain, an extremely rare and dangerous genetic disorder that dooms sufferers to a lifetime of hurting themselves in ways they cannot feel.

The COVID-19 outbreak in China's largest metropolis of Shanghai remains "extremely grim" amid an ongoing lockdown confining around 26 million people to their homes, a city official said Tuesday.

Director of Shanghai's working group on epidemic control, Gu Honghui, was quoted by state media as saying that the outbreak in the city was "still running at a high level."

The last time President Barack Obama was in the White House was on Jan. 20, 2017, when he left to escort his successor — bent on overturning "Obamacare" — to the U.S. Capitol to be inaugurated.

Obama returns to the White House on Tuesday for a moment he can savor: His signature Affordable Care Act is now part of the fabric of the American health care system, and President Joe Biden is looking to extend its reach. Obamacare sign-ups have increased under Biden's stewardship, and more generous taxpayer subsidies have cut costs for enrollees, albeit temporarily.