Children and adolescents have been seen as a relatively low-risk population during the pandemic. Data show that most children experience only mild symptoms of COVID-19 and so far they have not been found to be a major source of SARS-CoV-2 community transmission. However, the pandemic is evolving with the emergence of variants such as Delta, Lambda and Mu. In countries in which many adults are vaccinated, the relative incidence of COVID-19 in children and adolescents is rising. Severe COVID-19 is still rare in this group, but hospitalizations are increasing and symptoms of long-COVID do occur. Vaccines are still not available for children, nor for adolescents in many countries, and concerns about COVID-19 in the young are well-justified. A year and half into the pandemic, and with no end in sight, it is time to consider that the effects of COVID-19 in children go far beyond the symptoms of the disease itself. Indirect effects on health, education and social development have been devastating. A change of approach must happen now and the return to in-person schooling will be crucial to mitigate the long-term impact of these effects.

Online education is not feasible in low-income settings and even when used optimally, it cannot provide the same opportunity for social interaction and building healthy, stable relationships that the school setting provides. In-person schooling is therefore central to children’s wellbeing and must be a global priority as the pandemic continues to evolve. This is not without risk, but 1.5 years of intensive research has equipped public health officials with tools to monitor and mitigate SARS-CoV-2 transmission. The WHO and UNICEF have urged governments to make in-person schooling a “primary objective” and to put mitigation measures in place. What form these measures take will probably vary by region, according to vaccination guidelines, availability and uptake, community infection rates, and resources such as ventilation and classroom space.

Having successfully maintained in-person schooling for much of the pandemic, China, like many other countries, is now implementing a nationwide campaign to vaccinate schoolchildren aged 12–17 years to curb a rise in cases. Several European countries are supplying schools with CO2 sensors to monitor the level of exhaled air indoors, and these are being combined with the use of face masks and vaccinations, for those eligible. In India, measures include staggered attendance, limited class sizes, and vaccine mandates for staff. African nations are working to extend school reopening following a collaborative effort among ministries of education and health from 20 countries. But not all regions are taking a cautious approach; in the United States and the United Kingdom, a lack of adequate mitigation measures and mixed messaging have prompted concern from scientists and educators, amid rising levels of community transmission. Similarly, in much of Latin America, mitigation measures are lacking and school reopening, if any, has been slow.

The consequences of failing to curb transmission and keep children in school could be dire. At the peak of the first wave in April 2020, approximately 1.6 billion children were out of school. It is estimated that today’s children are several months behind expected learning milestones and will earn less over their lifetime as a consequence of disrupted schooling during the pandemic.

Along with frontline workers, children were among those most at risk of mental health issues during the pandemic. This is borne out by increased visits to mental health-related emergency departments and health insurance claims related to depression, anxiety, and substance abuse in the United States, particularly among adolescents—with studies across the globe reporting similar increases in depression and anxiety. Moreover, these issues have disproportionately affected children from low-income families, compounding pre-existing inequalities. For many children, school is a place where they can access support services such as counselling. The scale-up of mental health interventions and targeted learning strategies will be essential to reduce the inequality gap, and will require investment and training to be sustainable.

More time at home and on social media left many children susceptible to online abuse and domestic violence. In countries in which childhood marriage is legal and genital mutilation is practiced, these have increased during the pandemic, reversing progress made in recent years to curtail such abuse. Uninterrupted school attendance will mean more opportunities for education professionals to identify vulnerable children and to implement safeguarding measures.

Many children and families rely on meals provided by schools, and their closure, combined with disruptions to household income and social services, mean that childhood malnutrition is projected to increase. It is estimated that in low and middle income countries, an additional 9.3 million children will suffer from wasting between 2020 and 2022, owing to COVID-19-related disruptions. By contrast, in high income countries, childhood obesity is on the rise, which means a higher risk of severe COVID-19 in those infected and long-term increased risk of chronic conditions, including diabetes.

Even before the pandemic, many countries were failing to meet targets of 90% coverage for routine childhood vaccinations, and 2020 saw the biggest setback in decades. The absence of routine health services was compounded by school closures in regions in which vaccinations are mandated for attendance, and by flourishing anti-vaccine sentiments worldwide. In 2020, several million children missed doses of vaccines for diphtheria–tetanus–pertussis and measles, beyond what would have been expected in the absence of the pandemic. Recovery is underway, but gaps remain and recent outbreaks of measles underscore the urgency of the situation. Schools help to inform and educate parents and students to support vaccination programs. In countries in which COVID-19 vaccines are recommended and available for adolescents, funding for school-based vaccine clinics could ensure equal access, and provide an opportunity to check for and reschedule other missed vaccinations.

The true toll of the pandemic on children will only become apparent in the coming years, but it is still very much a modifiable outcome, if mitigation measures and targeted interventions to get children back on track happen now. A return to safe, in-person schooling will make the difference.