The number of COVID hospitalizations have doubled since early May as more transmissible subvariants of the already highly contagious Omicron variant--called BA.4 and BA.5--spread across the United States, federal health officials said Tuesday.

Still, deaths related to COVID remain low compared to the number of infections. Dr. Ashish Jha, the White House's COVID response coordinator, said the current death rate is not increasing with rising cases and hospitalizations due to the widespread availability of effective vaccines and antiviral drugs like Pfizer's (PFE  ) Paxlovid.

"We are at a point in the pandemic where most COVID-19 deaths are preventable," Jha told reporters during a White House COVID briefing on Tuesday. "Our strategy to manage BA.5 relies on making sure Americans continue to have easy and convenient access to these tools."

The seven-day average of hospital admissions is about 5,100 per day, CDC Dr. Rochelle Walensky told reporters on Tuesday, representing a doubling of hospital admission since early May. Currently, the seven-day average of daily death is about 350 per day, according to Walensky. Moreover, the U.S. is reporting an average of about 104,000 COVID infections per day as of Sunday, according to data compiled by the CDC, which is almost double the number of cases reported at the start of May.

Dr. Anthony Fauci, chief medical advisor for the Biden administration, told reporters that infections are undercounted because many people are using at-home tests that aren't reflected in the data. Fauci estimates the real number of daily infections is between 300,000 and 500,000.

The Omicron BA.4 and BA.5 subvariants now account for about 70% of COVID infections in the U.S., and the BA.5 subvariant is becoming the dominant strain. Fauci said BA.5 is more transmissible than past variants like Delta and Omicron as its has mutated to better evade the protection offered by current COVID vaccines. However, vaccines still generally protect against severe disease.

Walensky said that those previously infected with the original Omicron variants, BA.1 and BA.2, are still likely at risk of infection from BA.4 and BA.5.

The Biden administration is discussing the benefits of expanding eligibility for a second COVID booster to more populations, but that decision will need to be reached by the U.S. Food and Drug Administration (FDA) and CDC, Jha said. Last month, the FDA told vaccine makers like Pfizer and Moderna (MRNA  ) to update their formulas to target the BA.4 and BA.5 subvariants, as well as the original SARS-CoV-2 strain.