When covid-19 first began to spread around the world, pausing normal lessons was a forgivable precaution. No one knew how transmissible the virus was in classrooms; how sick youngsters would become; or how likely they would be to infect their grandparents. But disruptions to education lasted long after encouraging answers to these questions emerged.

New data suggest that the damage has been worse than almost anyone expected. Locking kids out of school has prevented many of them from learning how to read properly. Before the pandemic 57% of ten-year-olds in low and middle-income countries could not read a simple story, says the World Bank. That figure may have risen to 70%, it now estimates. The share of ten-year-olds who cannot read in Latin America, probably the worst-affected region, could rocket from around 50% to 80% (see chart 1).

Children who never master the basics will grow up to be less productive and to earn less. McKinsey, a consultancy, estimates that by 2040 education lost to school closures could cause global gdp to be 0.9% lower than it would otherwise have been—an annual loss of $1.6trn. The World Bank thinks the disruption could cost children $21trn in earnings over their lifetimes—a sum equivalent to 17% of global gdp today. That is much more than the $10trn it had estimated in 2020, and also an increase on the $17trn it was predicting last year.