If there is an issue that unites parents and the education community, and many other people, it has to be concern about school closures to fight the coronavirus. Many dislike them on a number of counts apart from inconvenience, even where there is acceptance of the need. Experts have warned about the harms of prolonged deprival of face-to-face teaching and interaction with other children during such a formative time. They include a decline in mental health, an increase in obesity and child abuse, impaired social development and, of course, loss of learning. Longer term, they may even affect job prospects and lifespans. Yet, two years into the pandemic, Hong Kong is closing schools again with fingers crossed they can soon be reopened. The city has already endured two sustained periods of home schooling. An extended time without local infections raised hopes there would be no more. The threat of an outbreak of the Omicron variant of Covid-19 has dashed them. Kindergartens and primary schools will close from today after three kindergarten pupils were found to have caught Covid-19 at home. This is understandable. Children can easily become infected and spread the virus. It is best to keep them home for everyone’s sake, given that children have not been vaccinated under current policy. In that respect, Hong Kong trails many other places, including the mainland. Thankfully, it is a vulnerability set to be remedied soon. Private Hong Kong clinic injects 36 people with expired Covid-19 vaccine The chief executive has announced that the age threshold for receiving the mainland-made Sinovac vaccine will be lowered from 12 to five after the Lunar New Year holiday. And a government expert advisory panel has recommended one-third strength doses of the German-made BioNTech vaccine for children as young as five, because the weaker paediatric version for under-12s is in short supply. Pfizer has long said that a dose one-third the strength of that for adults and adolescents is safe for children aged five to 11. The government should act without delay to implement its own advisers’ recommendation. The latest social-distancing measures have rocked Hong Kong just as its economy is recovering. They seem to have spurred more people to get vaccinated or seek booster jabs. It is particularly good to see that older people have been galvanised into getting jabbed by news that restaurants are to be included in the vaccination mandate from late February. But for a reassuring level of community immunity and resilience, it is especially important to get children jabbed, subject to detailed and science-based safety guidelines, as is happening in many other parts of the world.