Double and triple mutants of COVID-19 are same; vaccines effective on it: Scientist There is apprehension among experts that the new variant could also increase infection rates and easily surpass immune defences. By PTI| Posted by Nikita Venkatesh | Updated: 23rd April 2021 6:34 pm IST New Delhi: The double and triple mutant strains detected in India are one and the same variant of the coronavirus, and the available vaccines are effective on it, National Institute of Biomedical Genomics Director Soumitra Das said on Friday. Speaking at a webinar on ‘Genome Sequencing of SARS-CoV-19’, Das said double mutant and triple mutant terms are “colloquial” and both refer to the same variant — B.1.617 variant of the coronavirus.