Obama is throwing his 60th birthday bash on Martha's Vineyard with hundreds of guests amid Delta variant concerns

• Barack Obama is throwing his 60th birthday party outdoors on Martha's Vineyard, Axios reported.
• Sources said the party will have a "COVID-coordinator" and that guests are asked to be vaccinated.
• The CDC updated mask guidelines for vaccinated people last week over Delta variant concerns.

Former President Barack Obama is planning a massive outdoor party on Martha's Vineyard in Massachusetts next weekend to celebrate his 60th birthday as concerns over the Delta coronavirus variant rise.

Sources told Axios the hundreds of guests expected to be in attendance are asked to be vaccinated and that there will be a "COVID-coordinator" to make sure relevant protocols are followed. A source also said negative COVID-19 tests are required for every guest, but didn't give details on how that would be monitored.

The party is likely to be a star-studded event, with Oprah Winfrey and George Clooney rounding out the guest list, one source told The Hill.

Read more: Fight the Delta variant, but don't let it stop the reopening

Obama's 55th birthday party, held at the White House, was attended by Paul McCartney, Nick Jonas, Ellen DeGeneres, Stevie Wonder, and Magic Johnson.

Sources told Axios and The Hill the party is being held at the Obama's $12 million waterfront mansion. The seven-bedroom home sits on nearly 30 acres and has a swimming pool and private beachfront.

The party is being held amid renewed COVID-19 concerns. The Centers for Disease Control and Prevention recommended this week that everyone, vaccinated or not, should wear masks indoors in areas of the country with substantial or high coronavirus transmission.

Dukes County, where Martha's Vineyard is located, only has moderate community transmission, according to the CDC.

The updated guidance was prompted by new data on the Delta variant that showed vaccinated people can spread it as easily as the unvaccinated, Insider's Hilary Brueck reported.

The study the CDC considered was on an outbreak in an unnamed town in Massachusetts, a state with a high vaccination rate, that held multiple large gatherings, indoor and outdoor, in early July. Local media reports made clear the town was Provincetown, located on Cape Cod, which is north of Martha's Vineyard.

The study found 745 of the COVID-19 cases, or 346 infections, were among the fully vaccinated.

The CDC said the vaccines are still incredibly effective at preventing hospitalization or death, which is what they were intended to do, including with the Delta variant.