Drugmaker says lab tests show half-dose booster shot increased by 37 times the level of so-called neutralizing antibodies able to fight new strain of coronavirus

British health secretary won't rule out further regulations before end of week, with nation facing surge of infections; US senators Warren and Booker contract virus

White House's top medical adviser says dire situation in US hampered by fact that so many people are still not getting vaccinated, says virus is very unpredictable

Research carried out by NIAID, Moderna and other institutions showed vaccine was safe and effective against an HIV-like virus

Experts doubt current vaccines will become useless in face of new variant, but virus is currently moving faster than science

But top US medical adviser warns that the new COVID mutation is probably more contagious, and that it 'might take longer to see' its true severity

Chief US medical adviser says more studies needed, but it does not appear to be driving up hospitalizations despite rapid spread, hopeful US will lift Africa flight bans soon

Biden's top medical adviser Fauci says carrier is a twice-vaccinated traveler who returned from South Africa and is experiencing mild symptoms

Auschwitz memorial museum calls comparison 'shameful,' lamenting journalist's exploitation of Holocaust for use in modern-day debate on vaccines

Starting Monday, America will limit travel from South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi; Fauci says more info on variant still needed