As part of efforts to mitigate the impact of the coronavirus disease 2019 (COVID-19) outbreak, many countries have closed their schools. In Korea, the Ministry of Education had initially postponed the start of the new school year until March 23. Despite the declining number of new COVID-19 cases, the government has just ex-extended it to April 6.
It is challenging to make guidance on reopening schools because its impact on the containment of the COVID-19 outbreak is unpredictable. The issue gets more complicated by the data suggesting children are less susceptible to the novel coronavirus and less ill.
|Professor Choi Eun-Hwa|
Strategies to mitigate COVID-19 are rooted in the pandemic influenza preparedness plan. Non-pharmaceutical interventions provide time for mitigation in the case of pandemic influenza.
Historical findings demonstrated a strong association between early school closure and mitigation of the 1918–1919 influenza pandemic in the United States. Yet, a few observational studies and mathematical models have shown varied conclusions about the effects of reactive school closures in the course of influenza outbreaks. Models have generally predicted a reduction in the peak incidence of 20-60 percent. However, these predictions depend on the model's assumptions, and some studies have predicted no reduction in the attack rates.
Nonetheless, COVID-19 is not influenza, as it exhibits different viral kinetics, transmission dynamics, and clinical outcomes.
From the early epidemiological reports on COVID-19, we see a low frequency of cases and less severity among children. As of March 15, among 8,162 confirmed COVID-19 patients in Korea, only 83, or 1 percent, were aged under 9 and 427, 5.2 percent, were teenagers. Adults with COVID-19 transmit the virus during the asymptomatic or pre-symptomatic phase. A recent study on close contacts in China shows similar infection rates among children and adults.
In such a context, it is reasonable to presume children, too, are a source of transmission in the community despite their mild symptoms. As outbreaks are occurring in places where people interact with one another closely, transmission between children is likely to happen when schools open, thus triggering a second wave of the community infection. Opening of schools is also likely to increase contact rates in the community, reducing the effectiveness of social distancing, which is the mainstay of the current mitigation strategy.
Before ending shutdowns, schools need to prepare for the possible occurrence of COVID-19 on campus. The level of action and quarantine in the case of a school-outbreak will be significant and require the closure of affected schools. Standardized measures applicable to affected schools should be in place, such as detailed guidance for school closure, disinfection, and contact management.
At this moment, we do not have strong evidence to guide decisions on the duration of school closures and how different durations will affect public health.
A few days of closure are reasonable in response to school-based COVID-19 outbreaks for decontamination and contact tracing, while mid- to long-term closure (four to eight weeks) may be considered as part of a broader community mitigation strategy.
Extending school closure will likely support the overall effectiveness of social distancing and help to flatten the peak of the epidemic curve. The policy should maintain a balance between public health benefits and significant social consequences.
<The writer is a professor of the Pediatrics Department at Seoul National University College of Medicine. This article was originally published in the Journal of Korean Medical Science. >
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