Vacation flings are the stuff of bad romance movies and unhappy trips to the clinic, but now they are also the subject of two studies published in a British Medical Journal publication called Sexually Transmitted Infections. Two groups of researchers analyzed surveys of what British people do when they travel abroad and found that sex is high on the list.

One study, authored by population health researcher Clare Tanton and her colleagues, was an examination of 12,530 people who took part in the British National Survey of Sexual Attitudes and Lifestyles between 2010 and 2012. The group was composed of people from 16-74 years old, who reported having at least one sexual partner in the past five years. Out of this group, 9.2 percent of men and 5.3 percent of women said they found one or more new sexual partners while outside the UK. And out of those groups, according to Tanton and her colleagues, there was a lot of "disassortative sexual mixing," meaning cross-nationality intermingling.

In total, 72 percent of men said their overseas hookups were with non-UK residents, while 58 percent of women said the same. Interestingly, the study states that "men were less likely than women to report having partners from the Middle East/North Africa (2.4 percent vs 5.7 percent)." People who had sex with non-UK residents were also less likely to identify themselves by ticking the box for "White (British)" on the survey form.

These encounters were not just snogging sessions, either. The study defined sex as "vaginal, oral, or anal with someone of the opposite sex, and oral, anal (for men), or genital contact (for women) with someone of the same sex." People who had sex while overseas were also more sexually adventurous in general; they reported having more partners both at home and abroad, as well as multiple partners and partners of both sexes. These adventurers were not always having safe fun. They were less likely than the abstinent travelers to use condoms every time they had sex and (surprise) more likely to have been diagnosed with a sexually transmitted infection (STI). They were also more likely to get intoxicated using drugs or alcohol—though not necessarily during sex.

Tanton and her colleagues suggest that these findings lead to one basic conclusion, which is that travel can spread STIs across the world very rapidly. The rate of sexual mixing suggests that populations with low rates of STIs are being exposed to ones with higher rates. For example, chlamydia transmission rates are much higher in the UK than elsewhere in Europe, so when UK travelers hook up with non-UK residents, they may act as an infection "bridge" between the two populations. The same issue arises for UK travelers exposed to STIs that are more common abroad, who come home and spread the infection locally. The researchers recommend providing information about STIs and safer sex to travelers who leave the UK.

This is especially true in the case of backpackers, who were the subject of a second study of sexual activity among people backpacking in Thailand. "Over one-third of backpackers traveling without a longterm partner or spouse had vaginal and/or anal intercourse with a new partner; one-third of these did not use condoms consistently," write medical researchers C.T. Lewis and G. de Wildt in their paper. When it came to safer sex, Brits and Swedes were the most likely to report not using a condom during their escapades. Germans had less unsafe sex than Brits and Swedes but only because they hooked up less often. Canadians were most likely to say they'd used a condom and were also more likely to hook up with a new partner than other groups. (So the best travel sex is with Canadians, everybody.) Though Lewis and de Wildt admit that their findings may not be generalizable to all travelers, it's still a strong signal that backpackers would be a good target for a safer sex campaign.

Of course, these findings offer data that goes beyond who might infect whom with an STI. For one thing, they reveal that one out of 10 male travelers, and one out of 20 women, are going to get some action the next time they leave Britain. Plus, Brits on vacation like to get busy with people from other cultures, which seems very democratic. If there's any takeaway message for the intrepid British traveler, it's that packing condoms is a good idea. Always be prepared!

Sexually Transmitted Infections, 2016. DOI: 10.1136/sextrans-2015-052459 and DOI: 10.1136/sextrans-2015-052301