Travel agent associations in India and Thailand - countries battling an increase in covid-19 cases - have warned the public against tour operators advertising overseas travel for vaccinations saying there may be hidden costs.

Advertisements for travel to get the vaccine, mainly to the US, have sprung up on social media in India, despite restrictions that make international travel almost impossible. In Thailand, the number of tour packages that make available the chance to get in line for vaccination abroad is also growing.

"It is not illegal to go to the US, travel is absolutely a consumer choice," said Jyoti Mayal, president of the Travel Agents Association of India. "As an association, our advice is to check the credibility of the agent, check all the documents and go ahead."

Mumbai-based Gem Tours & Travels Unip has collected names of 5,000 people interested in staying for three days in New York to get the first dose of the vaccine and making another trip to get the second dose after several weeks, at a cost of about 150,000 rupees per trip.

Another operator, Dubai-based Arabian Nights Tours, announces "a trip for vaccination and happiness" in Russia. Starting at $1,780, the package includes round-trip tickets from Delhi to Moscow, 24 nights' accommodation in St. Petersburg and the Russian capital, and two doses of the Sputnik vaccine. Although "visa support" fees are included, the cost of the visa is not. There is also the chance that Russia will close borders with India, a factor that the tour operator says is not its responsibility, according to local media reports.

Thailand also has advertisements for vaccine tourism to the United States and Russia. One Bangkok operator is offering trips ranging from $2,400 to $6,400 to San Francisco, New York and Los Angeles, with prices depending on the time interval between doses and the brand of vaccine. Johnson & Johnson's has only one dose and would therefore require a shorter stay.

Many of the Thai packages do not include visa fees, airline tickets, meals, or the cost of a quarantine, if needed. Tour operators are also not responsible if travelers get sick from side effects of the vaccine, according to Suthiphong Pheunphiphop, president of the Thai Travel Agents Association.

Another question is whether travel is even practical, considering the border closures. India, for example, has suspended international commercial flights until May 31, and earlier this month the US banned most travel from India, although the restriction does not apply to US citizens or permanent residents.