Efforts to vaccinate the US may continue for years as Covid-19 variants circle the globe, expert says
Organ transplant patients may benefit from third Covid-19 vaccine dose to boost antibodies, study suggests
A dangerous Covid-19 variant on the rise could cause outbreaks in US states with lower vaccination rates, expert says
Have suitcase, will travel! Americans take to the skies in almost pre-pandemic numbers as Covid-19 restrictions ease
