The Biden administration will send out response teams made up mostly of government health experts to help areas of the United States experiencing an uptick in COVID-19 cases due to the highly transmissible delta variant.

“As we continue to work with communities across the country to get more shots in arms, we will also be working with governors and state and local health authorities to identify and address the needs on the ground in places with emergency outbreaks,” White House COVID-19 czar Jeff Zients said.

The “surge response” teams will include staff from the Centers for Disease Control and Prevention, the Federal Emergency Management Agency, and the Department of Health and Human Services Office of the Assistant Secretary for Preparedness and Response. The teams will provide help to states by supplying local health officials with more diagnostic tests and COVID-19 treatments, such as monoclonal antibody therapies.

Roughly 1,000 counties across the U.S. have vaccinations rates below 30%, CDC Director Rochelle Walensky said. These “most vulnerable” counties are primarily in the Southeast and the Midwest.

The delta variant, discovered in India, now accounts for over 20% of all active cases in the U.S. However, federal officials maintain that vaccinated people are safe from the variant, which has not been determined to cause more severe disease than the original strain, but it is estimated to be around 60% more transmissible than the highly infectious variant that was discovered in the United Kingdom.

The team deployments come just ahead of the Fourth of July weekend, when 47 million people are projected to be traveling to celebrate one of the first holidays after vaccines became widely available.

The nation will narrowly miss President Joe Biden’s goal of getting a shot to 70% of adults by Independence Day. To date, more than 66% of adults have received at least one dose of a vaccine, and nearly 58% have been fully vaccinated.