Over Half of COVID Transmission May Occur via Asymptomatic People

As COVID-19 cases surge and vaccinations lag, health authorities continue to seek additional ways to mitigate the spread of the novel coronavirus.

SARS-CoV-2 Transmission From People Without COVID-19 Symptoms

IMPORTANCE Severeacuterespiratorysyndromecoronavirus2(SARS-CoV-2),theetiologyof coronavirus disease 2019 (COVID-19), is readily transmitted person to person. Optimal control of COVID-19 depends on directing resources and health messaging to mitigation efforts that are most likely to prevent transmission, but the relative importance of such measures has been disputed.

Sorting Out Whether Vitamin D Deficiency Raises COVID-19 Risk

One of the risk factors du jour for coronavirus disease 2019 (COVID- 19) has been vitamin D deficiency.

Emergence of a Highly Fit SARS-CoV-2 Variant

Sarbecoviruses have emerged twice in the 21st century, causing a worldwide epidemic and pandemic.

U.S. Officials Say Covid-19 Vaccination Effort Has Lagged

The distribution of vaccines in the United States has gotten off to a slower-than-expected start, federal health officials acknowledged in a news conference on Wednesday, though they also voiced confidence that the pace would accelerate in the coming weeks.