Many US colleges and universities have informed the students to get vaccinated ahead of the Autumn semester. But the students who have been inoculated with India's Covaxin or Russia's Sputnik-V were asked to get themselves re-vaccinated saying that those are not approved by the World Health Organization (WHO).

"Milloni Doshi, a 25-year-old student from India, who is due to start her master's degree this fall at Columbia University's School of International and Public Affairs, has been administered two doses of Covaxin. Now, Columbia has told her that she needs re-vaccination if she wants to enter the campus," writes Rukmini Callimachi in The New York Times.\

"I am just concerned about taking two different vaccines. They said the application process would be the toughest part of the cycle, but it's really been all of this that has been uncertain and anxiety-inducing," Doshi wrote via a messaging app. This is primarily because no data exist on whether combining vaccines from different companies is safe.

It is advised that people who were vaccinated outside the US wait for a minimum of 28 days before taking the first dose of Food and Drug Administration (FDA)-sanctioned vaccines.

American students have access to the Pfizer, Moderna and Johnson & Johnson vaccines, three of the eight doses authorised by the global health body. As per sources, this situation is challenging for those 20,000 students from India who go to study there every year