The reopening of schools will put intense surveillance on the role of children in the Covid-19 pandemic.
The scientific advice is that they are less susceptible to the virus than adults and if they are infected the odds are very much against them falling ill.
But can they become drivers of the virus in a school, leaving adult teachers at risk? And what are the chances of them bringing the virus home and increasing its spread in the community?
These are questions which will be tracked when the school gates reopen and although evidence around the part played by children and young adults when it comes to risk and spread is growing, there is still a lot to learn.
Children appear to be at lower risk for contracting Covid-19 compared to adults. In Northern Ireland, no deaths were recorded for under-14s. Some 184 children under five in the Republic have tested positive for the virus and 340 were infected between the age of five and 14 years. The youngest person to die of the virus in the Republic was aged 17.
Reports suggest children are less likely to get Covid-19 than adults, and when they do they generally have a less serious illness. Adolescents aged 10 to 17 may be more likely to become infected but they also appear not to be at higher risk of developing a severe illness.
Children and adults with pre-existing conditions are at an increased risk of severe illness from Covid-19. Children with intellectual and developmental disabilities are more likely to have diseases of the respiratory system or heart, putting them at a higher risk.
Children as spreaders
A study from South Korea earlier this month suggested that children under 10 do not transmit the virus at the same level as adults pass it on to others. However, it can happen.
It suggested that older children and adolescents aged from 10 to 19 may spread the virus in the same way as adults. From what we know from other countries it seems the majority of children with Covid-19 were infected by a family member.
Published reports from contact tracing of students with Covid-19 in schools from France and Australia suggest that students are not as likely to transmit the virus to other students compared to household contacts. But research is needed on the transmission between children and members of their household.
Other countries are ahead on reopening schools and they have also changed the way they are run, introducing physical distancing measures, staggered opening times and pods where groups of pupils stay together.
Denmark, China, Norway, Singapore and Taiwan all imposed temperature checks at entrances to schools. In Taiwan, students returned to school with compulsory temperature checks and use of face masks.
The evidence to date is that a country with a low level of community transmission is well placed to take a chance on reopening schools.
The findings so far on whether the impact of returning to school leads to increased transmission of the virus or outbreaks are mixed. In Denmark there was a slight rise in cases in the community after schools reopened for younger children.
Israel suffered a significant increase in new cases and outbreaks in schools after it resumed schooling. The reports suggest so far that reopening schools where transmission of the virus is already high could see a further rise.
Experts say a good piece of work is still needed to give insight into what are the most effective mitigation measures.