Some 90,000 New York City children in pre-K and those with advanced disabilities went back to school for in-person classes on Monday.

The big picture: All other students in the city resumed classes online. Elementary schools are due to open on Sept. 29, with middle schools and high schools following on Oct. 1.

By the numbers: Nearly 200,000 people have died from COVID-19 in the U.S. Over 2.6 million have recovered and nearly 96 million have been tested for the virus. The U.S. has reported more than 6.8 million positive cases, according to Johns Hopkins University data.

What's happening:

Trends to watch:

Vaccine: All of a sudden, it feels like we're hurtling toward a coronavirus vaccine — with the first doses potentially being administered before the 2020 election.

All of a sudden, it feels like we're hurtling toward a coronavirus vaccine — with the first doses potentially being administered before the 2020 election. New risk factors: The CDC included more demographic groups at risk for the coronavirus such as younger people who are obese and who have underlying health problems.

The CDC included more demographic groups at risk for the coronavirus such as younger people who are obese and who have underlying health problems. When to wear a mask: Scientific evidence shows face masks can help control the spread of the virus, but nuances and changes in messaging about their use are complicating public health efforts.

Scientific evidence shows face masks can help control the spread of the virus, but nuances and changes in messaging about their use are complicating public health efforts. Elections: A federal judge in Wisconsin extended the state's deadline for counting absentee ballots, siding with Democrats in a lawsuit to make absentee voting easier in light of the pandemic. Judges in Georgia, Michigan and Pennsylvania have issued similar rulings.

A federal judge in Wisconsin extended the state's deadline for counting absentee ballots, siding with Democrats in a lawsuit to make absentee voting easier in light of the pandemic. Judges in Georgia, Michigan and Pennsylvania have issued similar rulings. Schools: Kids are heading back to school, as students, teachers, administrators and parents try to build a clear picture of how it's going to work.

Go deeper ... In photos: Life in the era of the coronavirus pandemic

Editor's note: The graphic includes "probable deaths" that New York City began reporting on April 14. This article has been updated with new details throughout. Check back for the latest.