Sweden, UK, also set new daily records as top WHO official says low hospitalization rates in South Africa are no guarantee Omicron will hit other countries as mildly

Tedros Adhanom Ghebreyesus warns against 'vaccine hoarding,' sets goal of 70% world vaccination rate by July

Series of experiments on mice, hamsters all reach same conclusion that new coronavirus strain mainly manifests in upper airway, causing fewer breathing problems

Registered infections up 37% since previous week and now stand at 6.55 million globally, the highest figures since the UN health agency declared a pandemic in March 2020

Even though it's facing much smaller outbreak compared with global virus hotspots, China has not relaxed its 'zero COVID' strategy, imposing stay-at-home orders in many areas

Number of cases multiplying in 1.5 to 3 days in places with community transmission, health organization warns

UN health agency cites data indicating infections from new variant are 'mild' or asymptomatic, predicts it will overtake Delta 'where community transmission occurs'

UN's top immunization official urges well-stocked countries to ease off on booster shots, enabling other countries to get initial doses

First research from South Africa indicates drop in effectiveness of Pfizer vaccine, but Omicron does not completely evade shot; boosters are beneficial

Rising Delta cases already force some governments to reintroduce restrictions; lab tests underway on Omicorn