The fast-spreading delta variant ripped through a federal prison in Texas over the summer, infecting both the unvaccinated and fully vaccinated populations, but few were hospitalized, according to a report published Tuesday by the Centers for Disease Control and Prevention.

The new report by the center’s Morbidity, Mortality Weekly Report shows that 185 of the prison’s 233 inmates were fully immunized against Covid19.

The CDC reported that Covid was found in 172 of those incarcerated, representing 74%, during July and August. According to the CDC, 39 of 42 unvaccinated prisoners were infected by the delta variant, with the remainder still not having received the vaccine. Compare that to the 129 illnesses infected out of 185 fully-vaccinated individuals.

According to the CDC, four people were admitted, including three unvaccinated. One person also died.

According to the agency, this report highlights the risk of delta variant outbreaks within congregate settings.

The agency stated in its report that although attack rates, hospitalizations and deaths were greater among those who had not been vaccinated, the duration of positive serial tests results was comparable for both.

The agency stated that it is crucial to continue vaccinating the majority of Americans as shots have been shown to be highly effective in preventing serious disease, hospitalizations, and death.

This new report is issued as federal health officials call on all Americans, particularly in large groups, to continue wearing masks indoors and get vaccinated against the highly contagious Delta variant.

Still, the U.S. has dangerously high numbers of cases. Johns Hopkins University data shows that the country is currently reporting more than 138.900 new cases each day. Hopkins data shows that there are an average of 1,900 deaths each day in the United States.

Earlier this month, President Joe Biden outlined a broad plan to boost Covid vaccination rates in the U.S., pressuring private employers to immunize their workforce as well as mandating the shots for federal employees, contractors and health-care workers.

This plan provides booster shots for Moderna and Pfizer’s vaccines to all citizens.

A Food and Drug Administration advisory committee on Friday unanimously recommended Pfizer booster shots to people age 65 and older and other vulnerable Americans. The agency will make a final decision within the next 24 hours.