The announcement was made Tuesday by Loudoun County schools Superintendent Dr. Scott A. Ziegler.
Fairfax County announced a similar requirement Monday.
Proof of a COVID-19 vaccine will be required for Loudoun County athletes participating in winter and spring sports and for all out-of-season practices for the 2021-22 academic school year.
Athletes participating in the five fall sports — football, cheer, cross country, volleyball and golf — are not subject to the vaccination requirement.
Ziegler said student-athletes are a particularly vulnerable group because they are required to travel to off-campus events and compete against student-athletes from other schools.
“The majority of past COVID-related disruptions to instruction for our high school students have come as a result of exposure during athletic activities,” Ziegler said.
Student-athletes who cannot be vaccinated due to a medical condition or religious belief will be required to submit a negative COVID-19 test result once a week before returning to play after an exposure to COVID-19, the county said.
“LCPS will not permit student-athletes with medical or religious exemptions who do not comply with the testing requirement to participate in school sports or related activities.”