CDC Update: Vaccinated Teachers and Students Do Not Need Masks Indoors

The Centers for Disease Control and Prevention (CDC) issued updated guidance, stating K-12 students benefit from in-person learning, and prioritizing safely returning to in-person instruction in fall 2021. The updated CDC guidance provides recommendations on masking for vaccinated individuals while indoors and outlines strategies for K-12 including unvaccinated populations to reduce the spread of COVID-19 and maintain safe operations.

Prevention Strategies to Reduce Transmission of SARS-CoV-2 in Schools

This revision of the CDC recommendations on COVID-19 prevention strategies points to the importance for in-person learning by students in K-12 schools. Due to this emphasis for in-person learning the CDC has provided schools with strategies where not everyone is fully vaccinated. These strategies include masking and physical distancing.

Since many schools serve children under the age of 12 who are not currently eligible for vaccination, the updated guidance emphasizes implementing a layered prevention strategy to protect those not fully vaccinated, including students, teachers, staff, and members of student households. The guidance is based on current scientific evidence and lessons learned from schools implementing COVID-19 prevention measures.

Together with local public health officials, school administrators should consider multiple factors when they make decisions about implementing layered prevention strategies against COVID-19. Since schools typically serve surrounding communities, decisions should be based on the school population, families and students served, as well as their communities. This is particular true in communities and regions of moderate-to-high community transmission levels. The primary factors to consider include:

  • Level of community transmission of COVID-19.
  • COVID-19 vaccination coverage in the community and among students, teachers, and staff.
  • Use of frequent SARS-CoV-2 screening/testing programs for students, teachers, and staff who are not fully vaccinated. Testing provides an important layer of prevention, particularly in areas with substantial to high community transmission levels.
  • COVID-19 outbreaks or increasing trends in the school or surrounding community.
  • Ages of children served by K-12 schools and the associated social and behavioral factors that may affect risk of transmission and the feasibility of different prevention strategies.

In communities and regions with low presence of disease and high vaccination coverage, the school administration may implement fewer or more relaxed COVID-19 prevention strategies. Included in the updated prevention strategies are some familiar language:

The CDC continues to recommend masking (for non-vaccinated individuals) and physical distancing, however if a school is considering whether and how to remove prevention strategies, one prevention strategy should be removed at a time and students, teachers, and staff should be closely monitored (with adequate testing through the school or community) for any outbreaks for increases in COVID-19 cases.

Promotion of Vaccinations

The CDC says vaccinations are currently the leading public health prevention strategy to end the COVID-19 pandemic. The CDC’s newest guidance recommends K-12 school administrators promote vaccinations to staff and students (over the age of 12) and stresses the need for localities to monitor community transmission, vaccination coverage, screening testing, and occurrence of outbreaks to guide decisions on the level of layered prevention strategies. The CDC says promoting vaccination can allow schools to safely return to in-person learning as well as add back extracurricular activities and sports.

Masking & Physical Distancing

The updated CDC guidance states, in general (vaccinated) people no longer need to wear masks indoors and masks should not be worn by children under 2 years of age. However for individuals who are not fully vaccinated, CDC says consistent and correct mask use is especially important indoors.

While outdoors, CDC says no-one needs to wear masks. However, where there is an area of substantial to high transmission, the CDC recommends that people who are not fully vaccinated wear a mask in crowded outdoor settings or during activities that involve sustained close contact with others who are not fully vaccinated.

The CDC recommends schools maintain at least 3’ of physical distance between students within classrooms, combined with indoor mask wearing by people who are not fully vaccinated, to reduce transmission risk. The updated guidance states, when it is not possible to maintain a physical distance of at least 3’, such as when schools cannot fully re-open while maintaining these distances, it is especially important to layer multiple other prevention strategies, such as indoor masking.

Ventilation in K-12 Schools

It is clear from the scientific and medical literature how important ventilation is to control and prevent transmission. The CDC stressed by reducing the number of virus particles in indoor air, such as when increasing fresh outdoor air into a building and making changes to the HVAC or air filtration systems, disease prevention can be achieved.

Additional ventilation recommendations for different types of school buildings can be found in the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) schools and universities guidance document.

Funds provided through the Elementary and Secondary Schools Emergency Relief Programs and the Governor’s Emergency Education Relief Programs can support improvements to ventilation. Please see question B-7 of the U.S. Department of Education Uses of Funds guidance for these programs.

RHP Professionals are experienced, knowledgeable, and credentialed to provide ventilation guidance for K-12 schools with effective and actionable steps towards the safe operations of K-12 schools through prevention, early detection, and control of COVID-19. RHP’s school ventilation system assessment services include a through audit of your school ventilation system performance and maintenance, tracer gas testing to measure actual air-change rate, verification of engineering and HVAC controls, and validation of efficacy of strategies. With many uncertainties associated with indoor air quality concerns, hazards, and risks, RHPs staff of public health professionals provide customized best-practice guidance and can assist with the development and implementation of customized building ventilation solutions. Contact RHP for an initial consultation at or call (773) 867-6010.