New Delhi, July 26 -- The delta variant is the fastest, fittest and most formidable version of Coronavirus, having the potential to infect even the fully-vaccinated people, virologists and epidemiologists have observed, raising concern at a time when most parts of the world are relaxing restrictions.

Protection from vaccination remains very strong against severe infections and hospitalizations caused by the majority versions of the coronavirus.

However, those unvaccinated are still at risk, leading COVID-19 experts were quoted as saying by Reuters.

Viruses constantly evolve through mutation and lead to new variants, which are often more infectious than the previous version.

As per experts, masks, social distancing and other measures r...