The rising spread of the COVID-19 Delta variant in Indiana state is causing concern as hospitalizations rise, US authorities said.

Iran PressAmerica: According to local health officials, the Delta variant appears more transmissible than the initial Alpha variant.

With the Delta variant spreading, Indiana state authorities said that the people were more likely to be hospitalized.

In another development, US President Biden's chief medical adviser Anthony Fauci on Sunday urged patience as studies examine whether additional "booster" vaccines would be another tool in warding off the coronavirus, particularly the highly contagious Delta variant.

Fauci called Delta "a very nasty variant" but stressed that the best protection is the current vaccine regimen recommended by US health officials.

Appearing on CNN's "State of the Union," Fauci told host Jake Tapper that US health regulatory agencies have to follow the data, which he said does not yet support the need for a booster shot. The CDC and FDA said last week that they "are engaged in a science-based, rigorous process to consider whether or when a booster might be necessary," but that fully vaccinated Americans do not need additional doses yet.