A gathering outside an intubated patient’s room in the pediatric ICU at Arkansas Children’s Hospital in Little Rock on Aug. 5. (Michael S. Williamson/The Washington Post)

With only about half of the U.S. population fully vaccinated against the novel coronavirus, hospitals across the country are straining to respond to a deadly fourth surge of infections driven by the delta variant.

Doctors say the nationwide outbreak overwhelming hospitals could have been avoided had more people been immunized. In the week ending Tuesday, 46 of the 50 states experienced double-digit growth in covid-19 hospitalizations, according to an analysis by The Washington Post. Eight states, including California and New York, which for most of the summer had not seen many serious cases, added more than 400 new inpatients in that time.