COVID-19 updates: Michigan, Minnesota, New Mexico leading nation in cases

The National Institutes of Health is starting a study to track the impact of COVID-19 infections in children, enrolling its first participant at the NIH's Clinical Center in Bethesda, Maryland.

The idea of “long COVID,” or long-term health impacts, is of concern in children, and is one of the reasons doctors strongly encourage pediatric vaccination. Six million children in the U.S. have had COVID-19, and many "experienced significant acute and long-term effects," the NIH said.

The study will track up to 1,000 children and young adults between 3 and 21 years old who previously tested positive for COVID-19 and evaluate the impact on their physical and mental health over three years.

The study will also try to determine risk factors for complications. It will evaluate the long-term immune responses to the disease, screen for genetic factors that may affect how children respond to COVID-19 infection and determine whether immunological factors influence long-term outcomes.

-ABC News' Eric M. Strauss

Dr. Anthony Fauci said vaccinated family members "can feel good about enjoying a typical Thanksgiving, Christmas," in an interview Monday hosted by the Bipartisan Policy Center.

But Fauci warned that cases are still high, so people should wear masks when they're in groups of people in indoor settings.

"We are not going to be going through this indefinitely," Fauci said. "How quickly we get to the end depends on us: how well we vaccinate, how well we get boosted and how well we do the kinds of things to protect ourselves."

-ABC News' Cheyenne Haslett

The daily case average in the U.S. now stands at 78,500 – a 23% jump over the last 2.5 weeks, according to federal data

Twenty-one states have seen an uptick in daily cases of 10% or more over the last two weeks: Arizona, Arkansas, Connecticut, Illinois, Indiana, Iowa, Kansas, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, Nevada, New Hampshire, New Mexico, New York, Ohio, Pennsylvania, Rhode Island, Vermont and Wisconsin.

Last week marked the first national increase in hospitalizations in nearly 10 weeks. There are now more than 47,000 patients with COVID-19 in hospitals -- up by about 2,000 patients since last Monday, according to federal data.

-ABC News' Arielle Mitropoulos

New York City Health Commissioner Dave Chokshi said he's issuing an advisory allowing all adults to receive a booster, as long as it's been six months since their last Moderna or Pfizer dose or two months since the Johnson & Johnson shot.

Chokshi asked New York City health care providers to "proactively reach out to their eligible patients -- particularly those 65 and older, those with medical conditions, and those who have received a Johnson & Johnson dose."

New York City is seeing an uptick in cases in recent days, Chokshi tweeted, adding that "booster doses can provide one more layer of reassurance, allowing us to breathe a bit easier, either for ourselves or our loved ones, particularly as we gather and travel around the holidays."