Travel agent associations in India and Thailand — both battling a surge in infections — have warned the public against operators advertising overseas tours to get vaccinated, saying there can be hidden costs.

Advertisements for vaccine tours, mainly to the U.S., have popped up on social media in India, despite restrictions that make international travel almost impossible. In Thailand, too, there are an increasing number of tour packages offering the chance to join a vaccination queue abroad.

"It’s not illegal to go to the U.S., traveling is absolutely your option,” said Jyoti Mayal, president of Travel Agents Association of India. "As an association, our advice is check out the credibility of the agent, check out all the documents and then move forward.”