here are few issues more polarising than whether schools should reopen during a pandemic. We know that online learning often isn’t as effective as regular classes, and that closing schools disadvantages the poorest and most vulnerable children in society. But people are still divided over the question of when it will be safe enough to restart in-person learning. While politicians have argued that schools are safe, unions say that teachers are being sent into unsafe workplaces. I’ve been helping to review the evidence on schools over the past 10 months for the Royal Society, which provides input to Sage and the Scottish government’s Covid-19 advisory group. The issue is far from clearcut: the science is still unfolding, particularly around the new variant, and the real question isn’t whether schools are safe or not, but how we balance various harms, benefits and risks. So far, we know that closing schools for everyone except vulnerable children and those of key workers entrenches educational inequalities. This has an irreversible effect on people’s life chances. No amount of financial support can completely mitigate or reverse these harms, because schooling goes far beyond literacy and numeracy; it’s also about social and physical development and providing safe places where children can access supportive adults. Moreover, we know the impact of school closures falls largely on women; during the first lockdown, 41% of working women struggled to find childcare to cover their hours. What’s also becoming clear is that we may have overestimated the effectiveness of closing schools. The return of schoolchildren in mid-August doesn’t appear to have been the driving force in the surge in cases many European member states experienced during the autumn, according to a recent review from the European Centre for Disease Control. There also seems to be a difference between primary age children (4-11), who are underrepresented in cases and outbreaks, and older children (11-18), who fall in line with other age groups. The scientific consensus is that children are largely unharmed by Covid-19. Although they may be carriers, they rarely experience its worst symptoms. Indeed, children up to age 18 have lower rates of hospitalisation and deaths than all other age groups. But this doesn’t mean they’re entirely unaffected; in the US more than 1,000 children have been admitted to hospital with MIS-C, a serious but rare condition associated with Covid-19. We still need to suppress Covid-19 in children, or we risk not only some of them being hospitalised but also giving the virus more chances to mutate. One of the main reasons for closing schools is the risk that infected children may pose to teachers. But, as the World Health Organization has noted, transmission between staff is the most common way the virus spreads. It’s less usual for the virus to transmit between staff and pupils, while the chances of the virus spreading from pupil to pupil are rare. It’s also not certain whether schoolchildren pose a risk to members of their household; one analysis of more than 9 million adults in England who shared a household with children aged 11 or under did not indicate an increased risk of Covid-19 (though it’s worth noting this analysis didn’t include teenagers). Instead of thinking about schools as zones of transmission that cause case numbers to rise across the population, it’s more accurate to think of them as reflections of the existing rate of transmission: when cases rise in a community, so do the number of outbreaks that occur in schools. But the latter is not necessarily the cause of the former. In Scotland, when schools were reopened full-time in August 2020, the country had managed to suppress Covid over the summer, and 75% of schools had no cases of Covid-19 in the first half-term. And half of the schools with Covid-19 only had a single case. But as the term continued into December, the rising number of school outbreaks coincided with rising positivity rates across communities. The new variant complicates this picture. Scotland made the decision before Christmas to delay reopening school until late January, except for vulnerable children and those of key workers. This was a precautionary move due to questions about the new variant, including how much more transmissible it is, how quickly restrictions can bring its prevalence down, and whether the variant changes the infectiousness of children. We still don’t have good answers to these questions, which is part of the scientific uncertainty that ministers must grapple with when making decisions. But we know far more than we did 10 months ago. The fastest way to get schools open is to reduce the number of infections across the population. This means we must all adhere to restrictions, limiting our mixing with others, avoiding indoor gatherings, staying away from crowds and remaining at home at much as possible. It’s also clear that reopening preschools, nurseries and primary schools will pose less of a risk to Covid transmission than reopening secondary schools. The greater challenge is keeping schools open for the foreseeable future, and avoiding a situation where outbreaks force bubbles and entire classes of children to isolate intermittently, disrupting their education. There are things the government could do to help schools remain open: it could deliver regular testing in schools to catch surges in infections, and provide supported isolation for students, ensuring they have a home computer, access to wifi, and that their parents have childcare support. It could prioritise teachers and school staff in the vaccination programme to ensure they feel safe and fully protected when doing their jobs. It could allocate funding to improve ventilation in classrooms and, as we head into spring, permit teachers to use outdoor spaces for classes. There are no simple answers to the question of when schools should reopen. Controlling transmission and ensuring we have a functional testing, tracing and isolating programme are both necessary steps. Listening to the concerns of teachers and school staff, and putting measures in place to detect any new school outbreaks, will also be vital. It is time to put political games and egos aside: what we need is a balanced discussion on how best we can move forward. An entire generation of children depends upon it. Prof Devi Sridhar is chair of global public health at the University of Edinburgh