COVID-19 updates: More than 10,000 new deaths reported in US in 1 week

New York City's Heath Department announced Wednesday it is investigating a cluster of COVID-19 cases that were linked to a Labor Day weekend concert.

At least 16 people have been identified as part of the cluster linked to the Electric Zoo music festival on Randall's Island, which is located in the East River, the department said.

Eight people have been also been identified who "though likely exposed prior to attending the concert," were in attendance while potentially contagious, according to the health department.

"Anyone who attended this festival should get tested immediately, regardless of whether or not they have been vaccinated. This is especially urgent if attendees are experiencing symptoms," New York City's health commissioner, Dr. Dave Chokshi, said in a statement.

The concert's organizers had strict rules for entrance.

Attendees had to show proof of vaccination that matched their photo ID. Unvaccinated ticket holders were allowed in if they showed proof of a negative test "no more than 3 days prior to each day of attendance," according to the concert's website.

The U.S. Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP) is planning to meet on Sept. 22 and 23 and is prepared to discuss COVID-19 vaccine boosters.

This will delay the potential start date of boosters until at least late next week, past the president's planned start date for boosters on Sept. 20.

The White House acknowledged that the start date is ultimately up to the CDC and Food and Drug Administration.

The FDA advisory panel is currently scheduled to hold a public hearing on boosters for the Pfizer vaccine and will have a non-binding vote later that day.

If the FDA approves, the ACIP will discuss and vote on recommendations, such as who should get the boosters and when.

The CDC director will make the ultimate decision on the boosters following the ACIP recommendations.

-ABC News' Eric Strauss

Moderna on Wednesday released its own analysis of various studies, making the case that the company's original vaccine appears to generate the strongest protection among the three currently authorized vaccines, but also saying people who got their vaccine will also need a booster six months later.  

Like Pfizer, Moderna is requesting authorization for a booster dose six months after the primary vaccination based on evidence that boosters are safe and generate immune response, and based on newly published data from its phase 3 trial showing a lower risk of breakthrough infections among people vaccinated eight months ago compared to people vaccinated 13 months ago.  

Unlike Pfizer, Moderna’s third booster will be a half-dose. Moderna says its data shows that boosting with a half-shot seems to generate more than enough immune response.  

-ABC News' Sony Salzman

In the last five weeks, the U.S. hasn't reported a single day with fewer than 100,000 new COVID-19 cases, according to federal data. In the nearly six months between Feb. 7 and July 29, there was not a single day with more than 100,000 new cases.

Nine states -- Alaska, Georgia, Idaho, Kentucky, Oregon, South Carolina, Tennessee, Washington and West Virginia -- currently have more patients hospitalized than at any other point in the pandemic, according to federal data.

But the CDC says hospital admissions will likely decrease over the next four weeks.

Death rates are also continuing to surge, with approximately 1,260 Americans dying each day -- up by nearly 50% in the last month, according to the data.

-ABC News' Arielle Mitropoulos