Preliminary study shows shot may not prevent transmission of South African strain, or stop mild and moderate cases -- though it might curb serious cases and deaths

Report says health officials investigating whether results indicate those who have been inoculated can still be infectious, without getting sick themselves

Despite highly efficient drive, it’s increasingly clear there will be no pandemic day-after moment. 'It will be very gradual in the coming months,' one expert says

Israel's surge in vaccinations means recent emigrants could get immunized sooner by flying home than staying put, but logistical hurdles make it near-impossible to achieve

US government health bodies warn there's not nearly enough data to prove efficacy, but doctors report no deaths among thousands of high-risk patients prescribed the new treatment

British health minister warns latest virus version 'appears to have mutated further than the new variant that has been discovered' in the UK

FDA clears the experimental drug called bamlanivimab, similar to one used to treat Trump, from Eli Lilly for people 12 and older with mild or moderate COVID-19