The Department of Homeland Security this week issued an intel notice warning that extremists, including white supremacists and other would-be domestic terrorists, are likely to “threaten violence or plot against healthcare personnel, facilities, and public officials in response to renewed and expanding COVID-19 mitigation measures.”

The document, distributed Monday to U.S. law enforcement and government agencies and obtained by ABC News, noted that anti-vaccine messaging will likely increase as vaccine mandates spread.

The notice warns that some of the misinformation and disinformation now circulating is being pushed and promoted by Russia, China and Iran as a means of sowing anger and discord in the U.S.

-ABC News' Josh Margolin

Seventy-six percent of Americans ages 12 and above have had at least one vaccine dose, White House COVID-19 data director Cyrus Shahpar said Tuesday.

Now 65% of the total U.S. population has had at least one dose, he said.

A federal judge has declined to impose a temporary restraining order on New York City’s public school vaccine mandate, rejecting a request from special education teachers who were denied a religious exemption.

Michael Kane and nine other educators -- who all said they possess sincerely held religious beliefs that compel them to eschew any vaccine -- sought the temporary restraining order, claiming the mandate violates the free exercise and equal protection clauses of the Constitution.

The educators can try again during a hearing next week at which they’ll seek a preliminary injunction, accusing the state of “hostility” toward religious beliefs that may be outside the mainstream.

New York City, the nation’s largest school district, is one of the first in the country to require school staffers to be vaccinated.

About 95% of the city’s 150,000 Department of Education employees have been vaccinated, including 96% of teachers and 99% of principals, Mayor Bill de Blasio said Monday.

About 8,000 replacement DOE staff members, including 7,000 substitute teachers, were used on Monday, which was the first day of the vaccination mandate.

-ABC News' Aaron Katersky

NIH Director Francis Collins announced that he's stepping down, saying in a statement that no person should serve for too long and it’s time to give space for the next generation of scientists to lead.

He was in the role for 12 years.

President Joe Biden in a statement called Collins "one of the most important scientists of our time."

Biden said he got to "know," "trust" and "lean on" Collins during his time as vice president, including when Biden led the National Cancer Moonshot.

Biden said he "was grateful" Collins "answered the call to serve" when Biden asked him to stay on at the start as his term as president, "even though it was asking him to stay on the job longer than anyone in NIH history."

-ABC News' Ben Gittleson

Last week, the U.S. reported more than 173,000 child COVID-19 cases, marking the first week with fewer than 200,000 new cases reported since mid-August, according to a newly released weekly report from the American Academy of Pediatrics and the Children’s Hospital Association.

Even with the decline, last week children still accounted for 26.7% of reported weekly cases. (Children make up 22.2% of the population.)

The South is reporting the highest number of pediatric cases followed closely by the Midwest.

The number of children hospitalized with COVID-19 is also declining. About 1,700 children are currently hospitalized across the country, according to AAP and CHA.

Severe illness due to COVID-19 remains "uncommon" among kids, the two organizations wrote in the report. However, AAP and CHA warned that there is an urgent need to collect more data on the long-term consequences of the pandemic on children, "including ways the virus may harm the long-term physical health of infected children, as well as its emotional and mental health effects."

-ABC News' Arielle Mitropoulos