Guidelines for Schools


Vaccination is the leading public health prevention strategy to end the COVID-19 pandemic. Promoting vaccination can help schools safely return to in-person learning as well as extracurricular activities and sports.


Indoor Masking - Due to the circulating and highly contagious Delta variant, CDC recommends universal indoor masking by all students (age 2 and older), staff, teachers, and visitors to K-12 schools, regardless of vaccination status.
Outdoor Masking - In general, people do not need to wear masks when outdoors. 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 other people. Fully vaccinated people might choose to wear a mask in crowded outdoor settings if they or someone in their household is immunocompromised.
School Transportation - CDC's Order applies to all public transportation conveyances including school buses. Passengers and drivers must wear a mask on school buses, including on buses operated by public and private school systems, regardless of vaccination status, subject to the exclusions and exemptions in CDC's Order.


Screening testing more than once a week might be more effective at interrupting transmission. Schools may consider multiple screening testing strategies, for example, testing a random sample of at least 10% of students who are not fully vaccinated, or conducting pooled testing of cohorts. Extracurriculars - To facilitate safe participation in sports, extracurricular activities, and other activities with elevated risk (such as activities that involve singing, shouting, band, and exercise that could lead to increased exhalation), schools should consider implementing screening testing for participants who are not fully vaccinated.

Physical Distancing

In addition to universal indoor masking, CDC recommends schools maintain at least 3 feet of physical distance between students within classrooms to reduce transmission risk. When it is not possible to maintain a physical distance of at least 3 feet, such as when schools cannot fully re-open while maintaining these distances, it is especially important to layer multiple other prevention strategies, such as screening testing.


Improving ventilation is an important COVID-19 prevention strategy that can reduce the number of virus particles in the air.During transportation, open or crack windows in buses and other forms of transportation, if doing so does not pose a safety risk. Keeping windows open a few inches improves air circulation.


Screening testing, ventilation, handwashing and respiratory etiquette, staying home when sick and getting tested, contact tracing in combination with quarantine and isolation, and cleaning and disinfection are also important layers of prevention to keep schools safe. Students, teachers, and staff should stay home when they have signs of any infectious illness and be referred to their healthcare provider for testing and care. Localities should monitor community transmission, vaccination coverage, screening testing, and occurrence of outbreaks to guide decisions on the level of layered prevention strategies (e.g., physical distancing, screening testing).

For more information, please see the CDC COVID-19 prevention in K-12 schools.

Understanding this Tool


The purpose of the tool is to equip you, as a school decision maker, with the ability to view and understand the effects that intervention strategies have on the spread of COVID-19 in your schools. Using the current number of cases and total population within your school's county, the tool calculates the expected percentage of your school that is currently infected, and then simulates the spread of COVID-19 given the intervention strategies you have selected.

Understanding the Interface

When the website is initially accessed, a window appears giving a general explanation of the tool. After closing this window, the interface is shown with a panel to input information on the left, and three tabs on the right. The first tab, 'Case Projections' tab displays the simulation outputs after you input your school's information (see below). The 'CDC Guidelines' tab outlines the CDC’s current recommendations for K-12 settings to reduce the spread of COVID-19. The 'User Guide' tab gives a general overview of how to use the tool and how the expected number of cases is calculated.

School Information

To simulate the expected number of cases for your school, you will need to enter your school's information in the left panel. Begin by selecting the county in which your school is located, school type (elementary school, middle school, high school, or other), number of students currently attending in-person, and number of in-person staff and faculty currently employed.

Intervention Strategy Inputs

You can simulate the impacts of masking, surveillance testing, and vaccinations on the spread of COVID-19. If you would like to see the expected number of cases given what your school is currently doing, toggle the intervention inputs to the current school policies. Alternatively, if you would like to see the expected number of cases with different interventions, toggle the intervention inputs to this 'what-if' situation. For example, if a school is currently at 25% masking but you would like to know the number of expected cases if masking was increased to 50%, simply toggle the 'Percentage of Mask Wearing' to 50%. You can also set the number of days you would like to observe case projections. The default is 2 weeks, but to change this value, simply change 'Projection Duration' to the desired duration.

Understanding the Outputs

After you input your school's information and desired intervention strategy plan, click the 'Submit Changes' button. The simulation outputs are displayed under the 'Case Projections' tab. You will see two graphs and some text.
The text at the top of the screen provides additional context for the output. Directly below this text is a graph showing the predicted number of cumulative cases for the duration of the simulation. The red plot shows the predicted number of cumulative cases if no intervention strategies are implemented (i.e. no masking, no surveillance testing, and the vaccination percentages you selected). The blue plot shows the predicted number of cumulative cases based on the intervention strategies you selected. The grey-shaded area represents a 95% confidence interval for projections each day. In other words, the simulation projects cases within this area with 95% confidence.
The text in between the two graphs provides an interpretation of the plots.
The second graph shows the predicted number of new cases per day across the duration of the simulation. The 'Predicted Number of New Cases' graph provides two plots: red shows the predicted cases with no intervention strategies, blue shows the predicted new cases with the selected intervention strategies.

Simulation Methodology

The decision-support tool intakes your inputs, data from the Georgia Department of Public Health for your school's county, and well-researched values for parameters (such as transmission rate, rate of recovery after infection, and proportion of (a)symptomatic infections). It is important to note that because some of these researched parameters have a range of values, multiple submissions with identical inputs may result in different outputs for the projected number of cases. The tool uses all the above-mentioned inputs to simulate COVID-19 cases 10 times and outputs two graphs. The first graph shows the average number of cumulative cases across all 10 runs, and the second graph shows the average number of new cases across all 10 runs for each simulated day.