Levels of childhood immunisations against dangerous diseases such as measles, tetanus and diphtheria have dropped alarmingly during the Covid-19 pandemic, putting millions of children at risk, United Nations agencies said on Wednesday.

"The avoidable suffering and death caused by children missing out on routine immunisations could be far greater than Covid-19 itself," World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus said in a joint report with Unicef.