World Health Organization (WHO) experts on Tuesday cautiously backed delaying second injections of the Moderna coronavirus vaccine in some situations, as they have already done for the Pfizer-BioNTech jabs.The WHO's Strategic Advisory Group of Experts on Immunisation (SAGE) also insisted that international travellers should not be prioritised for any Covid-19 jabs for the time being.During a meeting last week, the experts had discussed the Moderna vaccine, which, like the Pfizer-BioNTech one, uses mRNA technology and is being rolled out in a number of countries.Both vaccines require boosters after three to four weeks, but several countries facing limited vaccine supplies have said they will delay administering the second injection so that.