The B.1.617 variant of the coronavirus was first detected in India last year and has been blamed for much of a devastating Covid-19 wave that has battered South Asian nations in recent weeks.
"The situation was different with the AstraZeneca vaccine, which induced particularly low levels of antibodies neutralising" the Indian variant, the study said.
The Indian government has slammed the posts as "completely false," with officials concerned that the term "Indian variant" could hurt the country's reputation.
“It has come to our knowledge that a false statement is being circulated online which implies that an 'Indian variant' of coronavirus is spreading across the countries. This is completely false,” read the letter, obtained by AFP.