But she says the variant alone cannot be blamed for the dramatic surge in cases and deaths, adding that India appeared to have let its guard down with 'huge social mixing and large gatherings'.
The WHO plea comes after Canada authorised the use of Pfizer vaccine on children, with other rich nations set to follow suit.
Presiden Joe Biden menyifatkan inisiatif itu sebagai 'komitmen kemanusiaan yang penting' dari Amerika Syarikat.
WHO says the Covid-19 variant first found in India has been detected in over 1,200 sequences uploaded to the Gisaid open-access database from at least 17 countries including India, the UK, the US and Singapore.
They say the vaccine is safe and effective, and that the government should clearly explain the matter to allay public anxiety.
Health experts believe the actual death toll is far higher than official counts claim, with populous states accused of undercounting Covid-19 fatalities and cases
They say most clotting cases were reported in Britain and the European Union, with very few cases noted in other countries.