LONDON — People who have been infected with Covid-19 are likely to have some form of immunity for at least five months, according to early results of a major new study in the U. K. Preliminary findings in Public Health…

Countries around the world have closed their doors on the UK following the discovery of a new coronavirus variant. The variant—known as “B.1.1.7”—appears to have spread rapidly through London and the south-east of England. Although it appears to be more…

A new study has found evidence of a “robust cellular memory” against Covid-19 that lasts for at least six months after infection, reinvigorating the question of whether natural infection with the virus could grant lasting immunity after a study last…

A coronavirus vaccine the University of Oxford is developing with AstraZeneca Plc showed promising results in early human testing, which is a sign of progress in the high-stakes pursuit of a shot to defeat the pathogen. The vaccine increased levels…

Protection from any potential coronavirus vaccine might be short-lived and could require a booster to prolong protection, White House health advisor Dr. Anthony Fauci said Monday. As several companies move closer to the finish line of a potential vaccine for…