In late 2023, the New England Journal of Medicine published a paper by Wang et al. that noted a substantial increase in foetal situs inversus cases in two Chinese regions earlier that year.1 Foetal situs inversus is a rare congenital condition with a mirror image of inner organs, compared to normal organ development. Wang et al. included situs inversus totalis, with dextrocardia, and partial situs inversus, with levocardia, in their outcome definition. Their study reported a four-fold increase in situs inversus during the first 7 months of 2023 compared to the mean annual incidence in 2014–2022.1 This increase coincided with China lifting its zero COVID-19 policy from December 2022 to February 2023.1 This policy had focused on control and maximum suppression and involved finding, testing, tracing, isolating and supporting. It is estimated that 82% of the Chinese population had COVID-19 during this latter three-month period (percentage based on self-reported data).