The Centers for Disease Control and Prevention (CDC) has released updated COVID-19–related vaccination guidance. Health care facilities should use this information for National Healthcare Safety Network (NHSN) public health surveillance reporting. Specifically, they should use these terms and definitions when reporting data for Quarter 1 of 2025 (December 30, 2024 – March 30, 2025) and Quarter 2 (March 31 – June 29).

Under these definitions, individuals 65 years of age and older are considered up to date when they have received two doses of the 2024–2025 COVID-19 vaccine or one dose of the 2024–2025 vaccine within the past six months. Younger individuals are considered up to date if they have received one dose of the 2024–2025 COVID-19 vaccine. A resident with a newly positive SARS-CoV-2 viral test who has received a 2024–2025 COVID vaccine is considered in the up-to-date category if they got that vaccine 14 or more days before the specimen collection that showed the positive test result. 

This guidance is different from the previous definitions for Quarter 4 of 2024 (September 30 – December 29), where individuals were considered up to date if they received a 2024–2025 updated COVID vaccine or a 2023–2024 shot within the previous two months. A person with a newly positive SARS-CoV-2 viral test result who received a 2024–2025 updated COVID shot or 2023–2024 vaccine within the previous two months were counted as up to date if they received the vaccine 14 or more days before the specimen collection that led to the positive test result. 

The key terms and definitions are updated quarterly to reflect any changes as COVID-19 vaccination guidance evolves. NHSN calls for facilities to use the definitions for the reporting period associated with the reporting weeks included in their data submission.