Denise King, a staff member at Crown Heights Center for Nursing and Rehabilitation, a nursing home facility, receives the Pfizer-BioNTech coronavirus disease (COVID-19) vaccine from Walgreens Pharmacist Annette Marshall, in Brooklyn, New York, December 22, 2020.Yuki Iwamura | ReutersThe Centers for Disease Control and Prevention said Wednesday that an average of 60% of nursing home personnel in the U.S. are vaccinated against Covid, a rate officials say leaves the care facilities at higher risk for outbreaks among residents and staff.Vaccinating more employees is one of the most important steps nursing homes can take to keep residents safe, CDC epidemiologist Dr. Rachel Slayton said at a meeting of the agency’s Advisory Committee on Immunization Practices on Wednesday. Though administering booster doses to residents can help limit cases, Slayton said nursing homes remain vulnerable to outbreaks when staff members choose not to vaccinate.”Even with highly effective boosters, the community transmission is high in our model,” Slayton said. “That suggests that there will still be Covid-19 cases in nursing homes, highlighting the need for continued infection prevention and control strategies.”Slayton said Covid case projections forecast a decline in infections when staff immunization rates rose and residents received a supplemental third dose. Even though Covid infections continued to appear in Slayton’s model as more staff got vaccinated, she recorded a reduction in symptomatic cases among residents connected to higher staff immunization rates.Slayton’s report came as the CDC and Food and Drug Administration weigh whether to approve Pfizer’s Covid booster doses, a decision that could be made by Thursday.Nursing homes were hit particularly hard by the delta variant, officials said at the ACIP meeting. From March 1 through May 9, the National Healthcare Safety Network reported 17,407 weekly Covid cases in 3,862 nursing homes. But as the delta variant surged from June 20 through Aug. 1, NHSN recorded 85,593 weekly Covid cases in 14,917 nursing homes.To curb the delta variant, President Joe Biden issued a vaccine mandate on Aug. 18 for staff in approximately 15,000 nursing homes serving residents using Medicare or Medicaid. The Biden administration will block Medicare and Medicaid funding for any nursing home that fails to comply.Some nursing home operators even announced vaccine requirements before Biden’s guidance. Brookdale Senior Living CEO Cindy Baier told CNBC about her staff vaccine mandate on Aug. 6 in order to protect residents most susceptible to Covid complications.