Israel has begun trials of a fourth dose of coronavirus vaccine in what is believed to be the first study of its kind.

The trial began at Sheba Medical Center, outside Tel Aviv, with 150 medical personnel who received a booster dose in August receiving a fourth shot of the Pfizer/BioNTech vaccine. The staff receiving the additional dose were tested and found to have low antibody levels.

Christmas arrived around the world Saturday amid a surge in Covid-19 infections that kept many families apart, overwhelmed hospitals and curbed religious observances as the pandemic was poised to stretch into a third year.

From Bethlehem and Frankfurt to London and Boston, the surging coronavirus put a damper on Christmas Eve for a second year, forcing churches to cancel or scale back services and disrupting travel plans and family gatherings.

The biblical town of Bethlehem is gearing up for its second straight Christmas Eve hit by the coronavirus -- with small crowds and gray, gloomy weather dampening celebrations Friday in the traditional birthplace of Jesus.

A ban on nearly all incoming air traffic by Israel -- the main entry point for foreign visitors heading to the occupied West Bank -- kept international tourists away for a second consecutive year. The ban is meant to slow the spread of the highly contagious omicron variant, which has shaken Christmas celebrations around the world.

Nations around the world are lurching into lockdown, steeling themselves for a brutal surge as the omicron variant spreads like wildfire.

But in Dubai, Donna Sese is bracing for a very different surge: countless restaurant bookings and meter-long drink bills.

Two new British studies provide some early hints that the omicron variant of the coronavirus may be milder than the delta version.

Scientists stress that even if the findings of these early studies hold up, any reductions in severity need to be weighed against the fact omicron spreads much faster than delta and is more able to evade vaccines. Sheer numbers of infections could still overwhelm hospitals.

China shut down a city of 13 million people on Thursday in a bid to extinguish a tiny Covid-19 outbreak and chase its zero-case goal, as other nations around the globe battled huge infection surges driven by Omicron. 

Queen Elizabeth II has decided not to spend Christmas at the royal Sandringham estate in eastern England amid concerns about the fast-spreading omicron variant.

The palace said Monday that the 95-year-old queen will spend the holidays at Windsor Castle, west of London, where she has stayed for most of the pandemic.

Moderna said Monday that a booster dose of its COVID-19 vaccine should offer protection against the rapidly spreading omicron variant.

Moderna said lab tests showed the half-dose booster shot increased by 37 times the level of so-called neutralizing antibodies able to fight omicron.

The World Economic Forum is again delaying its much-ballyhooed annual meeting of world leaders, business executives and other elites in Davos, Switzerland, amid new uncertainties about the omicron variant of the coronavirus.

The forum, which repeatedly delayed, moved and finally canceled last year's event, says the previously planned Jan. 17-21 gathering in the alpine town will now take place in "early summer" — without giving specifics.