'Steady increase' in vaccines in past month, White House says

President Joe Biden is expected to announce a vaccine mandate for the nation’s 2.1 million federal employees on Thursday, ABC News has learned.

Details around the policy are still being reviewed by the White House, however, sources familiar with the discussion told ABC News that employees who aren't vaccinated will abide by "stringent COVID-19 protocols like mandatory mask wearing – even in communities not with high or substantial spread - and regular testing."

Once enacted, this will be the largest vaccine mandate by a single employer of this pandemic.

New York City and the state of California announced Monday similar rules for their public employees.

White House sources also told ABC News that following the Centers for Disease Control and Prevention's new recommendations on indoor mask use, the president will wear a mask when he travels to areas where the transmission rates are high and he needs to be indoors.
-ABC News' Cecilia Vega and Sarah Kolinovsky

Just hours after the Centers for Disease Control and Prevention changed its policy on indoor mask use for vaccinated Americans, the agency sent out an alert to doctors, pressing them to step up vaccines.

The Health Alert Network Health Advisory reiterated that vaccine coverage needed to go up "to prevent surges in new infections that could increase COVID-19 related morbidity and mortality, overwhelm healthcare capacity, and widen existing COVID-19-related health disparities."

As of Tuesday, 66.6% of Americans above the age of 12 have received one vaccine dose, however the rates are lower in several southern states including Louisiana, Alabama and Mississippi. Those states, the alert noted, have seen a major jump in COVID-19 cases, hospitalizations and deaths.

"Unvaccinated persons account for the majority of new COVID-19 infections, hospitalizations, and deaths," the CDC said in its alert.

-ABC News' Anne Flaherty

The COVID-19 outbreak in Provincetown, Massachusetts, has now grown to at least 765 people, officials said Tuesday.

The number of cases from the popular tourist destination have been increasing since the Fourth of July weekend.

Of these cases, 469 individuals are Massachusetts residents, 199 of whom reside in Provincetown, Town Manager Alex Morse wrote in a Facebook post.

The remaining individuals who tested positive reside in other states, or jurisdictions, he said.

There have been no reported deaths linked to the cluster so far, however, three people linked to it have been hospitalized. One of the patients was vaccinated, according to town officials.

-ABC News' Arielle Mitropoulos

The Centers for Disease Control and Prevention on Tuesday reversed its mask guidance for vaccinated people due to the delta variant surge. 

Vaccinated Americans should now wear masks inside if they’re in places with substantial or high transmission, the CDC said.

CDC Director Rochelle Walensky said data show that on "rare occasions, some vaccinated people with the delta variant … may be contagious and spread the virus to others. This new science is worrisome and unfortunately warrants an update to our recommendations."

Walensky added, "This moment -- and most importantly -- the associated illness, suffering and death, could have been avoided with higher vaccination coverage in this country."

In May, the CDC said vaccinated Americans could stop wearing masks indoors.

The CDC also said Tuesday that masks should be worn in schools by all students, teachers, staff and visitors, even for those who are vaccinated. The CDC said students should return to full-time in-person learning this year with prevention strategies in place.

President Joe Biden in a statement called the CDC's new rules "another step on our journey to defeating this virus."

"While we have seen an increase in vaccinations in recent days, we still need to do better," he added.

-ABC News’ Anne Flaherty and Eric Strauss