A top World Health Organisation official estimated Monday that Covid-19 vaccination coverage of at least 80% is needed to significantly lower the risk that ‘imported’ novel Coronavirus cases like those linked to new variants could spawn a cluster or a wider outbreak.

Dr Michael Ryan, WHO’s emergencies chief, told a news conference that ultimately, “high levels of vaccination coverage are the way out of this pandemic.” Many rich countries have been moving to vaccinate teenagers and children who have a lower risk of more dangerous cases of Covid-19 than the elderly or people with comorbidities, even as those countries face pressure to share vaccines with poorer ones that lack them. Britain, which has vastly reduced case counts thanks to an aggressive vaccination, has seen a recent uptick in cases attributed largely to the delta variant.