The World Health Organization (WHO) estimates that less than 10 per cent of the global population have antibodies to the coronavirus, WHO Chief Scientist Soumya Swaminathan said.

"Less than 10 per cent of the world's population actually has antibodies to this virus. Of course in some settings, like particularly in the very high-density urban settlements, there are pockets where 50, 60 per cent of the population has been exposed to the virus and has antibodies," Swaminathan said in a Sunday interview, released on the official WHO Twitter handle.

The only way to achieve mass herd immunity is through vaccination, the WHO chief scientist stressed.

According to Swaminathan, the currently approved vaccines offer good protection against severe disease, hospitalization and death from COVID-19. The vaccines' effectiveness with regard to mild disease and asymptomatic coronavirus infection is still being studied.

More than 114 million coronavirus cases have been confirmed globally since the start of the pandemic last spring. According to Johns Hopkins University data, the global COVID-19 death toll stands at over 2.5 million.