Children And Risk Of COVID-19 In Schools

Children And Risk Of COVID-19 In Schools Children And Risk Of COVID-19 In Schools
Peter Teska
Global Infection Prevention Expert
Mar 05, 2021

With the number of cases of COVID-19 declining globally over the last month, countries are starting to take measures to reopen facilities that had been closed or limited in use during the peak of the pandemic. Both the World Health Organization (WHO) and US-Centers for Disease Control and Prevention (CDC) are issuing recommendations for reopening various facilities.


One of the areas that has proven to be more controversial in some countries is the reopening of schools. This article briefly discusses both the WHO and CDC recommendations/strategies and some of the key issues associated with schools. It also discusses why the US-CDC is recommending that reopening of schools can occur prior to vaccination of students and teachers/staff.


Risks of School Closures:

Prolonged school closures are associated with a number of negative outcomes for children. The WHO states that there are risks of a reversal in educational gains, limiting future educational opportunities, potential social and emotional issues for children, and delayed development (2020). Additionally the WHO (2020) comments that school closures can interrupt essential school based services, such as feeding and nutrition, immunization, and mental health support. The CDC states that the risk to children from school closures is so serious that during a pandemic schools should be the last facilities closed and the first ones reopened (CDC, 2021).


Infection Risk of Children:

Children are well known to be susceptible to a range of common respiratory infections, such as influenza, rhinovirus, and common coronaviruses. When unvaccinated, they are highly susceptible to more serious respiratory diseases such as measles, mumps, and pertussis (whooping cough). 

From the start of the COVID-19 pandemic, children were reportedly infected with SARS-CoV-2 at lower rates than adults, with younger children (0-11) infected at even lower rates than older children (12-18). Because many countries closed schools during the first phases of the pandemic, it was not clear whether lower infection rates in children were because children were less susceptible to SARS-CoV-2 or whether being quarantined at home interrupted normal routes of transmission for children associated with schools.

A study in the US (Fisher, 2020) of activities that increased the risk of SARS-CoV-2 infection showed that adults that were infected were much more likely to have eaten in a restaurant (2.8 times more likely) or been to a bar or coffee shop (3.9 times more likely) within 2 weeks of getting infected than people that did not visit these facilities. If children are generally less likely to be in restaurants, bars, and coffee shops, then a major risk factor that is present in adults is absent in children, which could help explain the lower infection rate in children.

Early studies showed that most (52%) children that do get infected with SARS-COV-2 are likely infected by a family member (Zachariah, 2020). Children also appear more likely to develop milder disease, but they can become severely ill and die, however this is rare. Data from the US through the end of Jan 2021 shows that of 478,912 deaths, only 204 were for people under 18 years of age (0.043%) versus people 85 and over which represented 151,344 deaths, or 32% of all deaths (CDC, 2021). Globally the WHO estimates (2020) that children comprise 8.5% of all reported COVID-19 cases with fewer reports of severe disease or death.

In a 2020 study, Heald-Sargent (2020) tested for SARS-CoV-2 in nasopharyngeal swabs and found that children 5-17 had comparable viral loads to adults, but that children <5 years old had higher viral loads. This demonstrates that children of all ages can transmit the virus and younger children may be able to more readily transmit the virus even if they are less likely to become seriously ill or die from the infection.


Children Causing Infections:

Several cases studies have demonstrated that even if children rarely become seriously ill with COVID-19, children can be super spreaders for SARS-CoV-2. In one report (Schwartz, 2020) a teen (13F) staying in the same house with 13 family members over a 3 week period as part of a family vacation infected 11 of the other 13 people. Six other relatives that visited, but stayed outdoors and maintained physical distancing, did not get infected. If children are capable of spreading the virus, then being in facilities where conditions favor infecting others are important in understanding the transmission risk in schools.

A recent high school wrestling tournament in Florida in the US was the source of a super spreading event where 13 teenage wrestlers who were asymptomatically COVID-19 positive caused 38 infections in other wrestlers over the 2 day event (Atherstone, 2021). Among close contacts an additional 41 people were infected including family members and other team members that did not attend the tournament. High school athletics where mask wearing is not possible and physical distancing cannot be maintained are at higher risk for transmission of SARS-CoV-2 (Atherstone, 2021). 

In Wisconsin in the US during September – November 2020, a study was done to compare infection rates for students and staff in seven K-12 schools versus the community. With widespread mask usage (>92%) and other public health practices being enforced, COVID-19 infection rates of students and staff were lower than in their communities (Falk, 2021). Overall 133 students and 58 staff were detected as being infected and seven case of transmission were associated with the school environment, all student to student transmission, and rate of transmission in these schools was 37% lower than in the general community (Falk, 2021). This study suggests that with proper mitigation measures, K-12 schools can open with an acceptable level of risk of SARS-CoV-2 infection for students and staff. It also inherently suggests that not following recommended mitigation measures can create situations for outbreaks.  


CDC and WHO Recommendations for Safe Reopening:

In Feb 2021, the CDC (2021) issued updated strategies for K-12 schools. They state the following:

"While risk of exposure to SARS-CoV-2 in a school may be lower when indicators of community spread are lower, this risk is also dependent upon the implementation of school and community mitigation strategies. If community transmission is low but school and community mitigation strategies are not implemented or inconsistently implemented, then the risk of exposure and subsequent transmission of SARS-CoV-2 in a school will increase."

This means that no matter how low the community infection rate, if the school does not follow the recommended practices, the infection risk will be higher. The CDC recommendations include:

  • Use of layered mitigation strategies to reduce transmission. This means a bundle of interventions, rather than a single intervention. Recommended interventions include:
    • Universal and correct use of masks (with 2-3 layers of fabric) for all students, staff, and visitors. Younger students and those with disabilities or certain health conditions may not be able to use masks.
    • Physical distancing of at least 6 feet whenever possible. This may mean limiting the number of students in the room at one time. Cohorting or podding is also recommended to minimize exposure across the school.
    • Hand hygiene
    • Respiratory hygiene/etiquette
    • Environmental cleaning and maintaining healthy facilities
      • Routine cleaning and disinfection of frequently touched surfaces
      • Modify physical layouts, such as turning desks to face in the same direction
      • Use physical barriers and guides to direct flow
      • Discourage shared items, especially if they are difficult to clean
      • Ensure the water system is safe if it has not been used during a facility shutdown
      • Close communal spaces or stagger use, cleaning between uses.
      • Avoid self-serve food and beverage stations.
      • Improve ventilation to the extent possible by increasing air flow or opening windows and doors.
    • Contact tracing in combination with isolation and quarantine as needed, working with the local health department.
  • Using the community infection rate as a guide to understand the community risk. New cases per 100,000 people in the surrounding community and the percent of PCR tests that are positive are the 2 measures recommended.
  • Phased mitigation and learning based on the level of community transmission.
  • Testing to identify students and staff with SARS-CoV-2 infection. In schools with a nurse on site, rapid point of care diagnostic tests may be used to detect asymptomatic infections and for testing of close contacts. Symptomatic people can be referred to healthcare facilities that will perform diagnostic testing and should not be allowed on campus and no sick students or staff should be allowed to attend school. When a healthcare professional is not available, public health screening tests to identify asymptomatic people may be used. These tests are often saliva based rapid antigen detection tests. All testing should be on a voluntary basis and testing of students under 18 will require consent from a parent or legal guardian.
  • Vaccination for teachers and school staff as soon as supply allows. While teachers are not generally prioritized in the first groups to be vaccinated, their critical role in providing education warrants inclusion in the next groups vaccinated. Since states set their own prioritization, prioritization of teachers and student facing staff may vary from state to state. While the CDC states vaccination of teachers should not be considered a condition for school reopening, additional precautions may be needed until vaccination is available. Teachers unions have been concerned about schools resuming face to face instruction without vaccination, making this a controversial issue. Many teachers are older people with underlying health conditions, putting them a higher risk for serious disease if infected. The lack of funds for many schools to implement all the recommended CDC strategies suggests these schools will be at higher risk for transmission, with risk of serious disease being much more for teachers and staff than for the students.
  • In-person instruction should be prioritized over extracurricular activities including sports and school events. Suspending these activities can play a major role in controlling risk in the school environment.
  • Families with high risk family members should be given the option of virtual learning.
  • Schools with younger students (Elementary Schools) should be prioritized for face to face instruction as the impact of face to face instruction is higher for younger students.
  • If using a hybrid educational model, prioritize in-person instruction for students with disabilities.

The CDC also states (2021):

"Despite careful planning and consistent implementation of mitigation, some situations may occur that lead school officials to consider temporarily closing schools or parts of a school (such as a class or grade level) to in-person instruction. These decisions should be made based on careful considerations of a variety of factors and with the emphasis on ensuring the health and wellness of students, their families, and teachers and staff."

Thus the emphasis should be on safely reopening schools, not just getting them reopened. Until widespread vaccination is available later this year, the risk of outbreaks associated with schools will continue to be a controversial issue. However the CDC’s position is clear that if mitigation measures are followed, the risk to students and staff will be lower than in the general community.



Attending schools are important for the social and educational development of children. The COVID-19 pandemic forced school closings in many areas, causing hardships for students and their families. Concerns about how to safely reopen schools or resume face to face instruction have risen as COVID-19 case numbers have dropped. The CDC published strategies for schools to use to provide a safe learning environment and this document reviewed the proposed strategies.



  • Atherstone C, et. al. SARS-CoV-2 transmission associated with high school wrestling tournaments – Florida, December 2020 – January 2021. MMWR. 2021; 70: 1-3.
  • Centers for Disease Control and Prevention. Operational strategy for K-12 schools through phased migration. 2021. Retrieved from:
  • Centers for Disease Control and Prevention. Weekly updates by select demographic and geographic characteristics. 2021. Retrieved from:
  • Falk A, et. al. COVID-19 cases and transmission in 17 K-12 schools – Wood County, Wisconsin, August 31 – November 29, 2020. MMWR. 2021; 70: 1-5.
  • Fisher KA, et. al. Community and close contact exposures associated with COVID-19 among symptomatic adults ≥18 Years in 11 outpatient health care facilities - United States, July 2020. MMWR, 2020; 69(36): 1258-1264.
  • Heald-Sargent T, et. al. Age-related differences in nasopharyngeal Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) levels in patients with mild to moderate Coronavirus Disease 2019 (COVID-19). JAMA Pediatrics. 2020. doi:10.1001/jamapediatrics.2020.3651
  • Schwartz Ng, et. al. Adolescent with COVID-19 as the source of an outbreak at a 3-week family gathering – four states, June-July 2020. MMRW 2020; 69(40); 1457–1459.
  • World Health Organization. Checklist to support schools re-opening and preparation for COVID-19 resurgences or similar public health crises. 2020. Retrieved from:
  • Zacahariah P, et. al. Epidemiology, clinical features, and disease severity in patients with coronavirus disease 2019 (COVID-19) in a children’s hospital in New York City, New York. JAMA Pediatrics. 2020; doi:10.1001/jamapediatrics.2020.2430