White House COVID coordinator Jeff Zients touted the recent increase in vaccine rates across the country during a briefing Monday.

He said last week the U.S. reached its highest day seven-day average of vaccinations since July 4th, and 3 million Americans got their first shot in the past seven days.

Zients noted that the most significant increases were in the states with the highest COVID-19 rates, where vaccination rates have doubled and, in some cases, tripled.

"Louisiana has seen a 302% increase in the average number of newly vaccinated per day, Mississippi, 250%, Alabama 215% and Arkansas 206%," Zients said.

He reiterated that the jump in vaccines will help to bring cases down throughout the country.

-ABC News' Cheyenne Haslett

The town leader of Provincetown, Massachusetts, said the city is "well on our way to containment" following the outbreak of over 880 COVID-19 cases since July.

Provincetown Town Manager Alex Morse said in a Facebook post Monday evening that the total number of active cases among Provincetown residents decreased to 59.

Positivity rates have been under 5% the last three days, down from a peak of 15% on July 15, according to Morse.

"The number of people recovering each day far exceeds the number of new cases being added. We are optimistic this will continue," Morse wrote.

As of Monday, 882 people, including 231 Provincetown residents, have contracted the coronavirus since the cluster cases emerged following the Fourth of July weekend.

Only seven hospitalizations associated with this cluster have been reported to date two of whom were out of state residents, and those patients have been released, health officials told ABC News. No deaths from this cluster have been reported so far, Morse wrote.

-ABC News' Arielle Mitropoulos

Michigan health officials are urging attendees of a recent motorcycle event to get tested after 16 COVID-19 cases were linked to it.

The Michigan Department of Health and Human Services said they are investigating the outbreak that was linked to the Muskegon Bike Time event, which was held from July 15 to 18.

Some individuals were at the event while they were infected, according to the health department.

"Attendees at Bike Time may have been exposed and are urged to get tested based on CDC’s latest guidelines," Dr. Joneigh Khaldun, the chief medical executive and chief deputy for health at MDHHS, said in a statement.

-ABC News' Darren Reynolds and Josh Hoyos

Health officials from eight Bay Area counties, including San Francisco and the city of Berkeley, announced Monday they will be reinstating a mask mandate for all residents for indoor activities.

The new orders go into effect at midnight. The order comes as COVID-19 cases and hospitalizations are on the rise in California, due to the delta variant, according to officials.

"While there may be slight differences between each jurisdictions' orders issued today, they all have one thing in common. A simple step, wearing a mask indoors to provide one more layer of protection for everyone," Dr. Chris Farnitano, the health officer for Contra Costa County, said at a news conference.

Thirteen theaters in Washington, D.C., have joined forces to require audiences to supply proof of vaccination in order to attend live performances at indoor venues.

In addition to the vaccination requirement, masks will be required inside the theaters. Medical and religious exemptions to the rule will be accepted, but those patrons will have to show proof of a recent negative COVID-19 test in order to gain entry. For children younger than 12, patrons should contact the theater directly for more information about individual policy.

More theaters are expected to join the cohort in comings weeks, according to Theatre Washington, an alliance of theater organizations and supporters.