More than 50 major health care organizations have signed a letter urging health care and long-term care employers to require their employees to get vaccinated against COVID-19 as cases begin to rise again across the U.S.

We call for all health care and long-term care employers to require their employees to be vaccinated against COVID-19, the organizations said in the letter published Monday. The American Medical Association, the American Academy of Pediatrics and the American College of Physicians are among the groups that signed on to the letter.

The groups cited the highly contagious delta variant of the coronavirus, which has been spreading among unvaccinated people, for the recent surge in new COVID-19 cases, hospitalizations and deaths across the U.S.

Vaccination is the primary way to put the pandemic behind us and avoid the return of stringent public health measures, the letter states. Unfortunately, many health care and long-term care personnel remain unvaccinated.

About 25% of hospital workers who work directly with patients had not received even one COVID-19 vaccine shot as of May, according to a WebMD and Medscape Medical News data analysis of 2,500 hospitals across the country.