Last year, Kate Webster started to feel unwell during a flight from Africa back home to Australia.
She initially put it down to one too many drinks the night before — but by the time she touched down, the Gold Coast travel journalist was so sick she had to be taken off the plane in a wheelchair.
The 37-year-old had been struck down with malaria while travelling through Uganda, and she ended up spending two months in hospital as she battled the deadly disease.
It took another six months to get back to "normal" — although she still endures frequent bouts of sickness as a result of the disease.
As she recovered, Ms Webster, who edits travel blog Captured Travel, ended up missing out on around $9600 in lost income, and was also left out of pocket due to many other medical and personal expenses.
But a travel insurance loophole meant her travel insurer didn't pay her a cent.
"I took months off work because I was bedridden … it ended up costing me, but the insurance company turned around and said because I was treated in Australia, they couldn't pay my claim," she told news.com.au.
"Clearly, malaria isn't a disease you get in Australia so it was really frustrating. Had I gone to hospital there they would have had to fly my family members over and fly me home and it would have cost them more.
"It was really poor timing, the fact it hit me on the plane instead of the day before."
But that's not the only travel insurance loophole that could sting Aussie travellers.
According to a recent analysis by comparison site finder.com.au, one in seven Aussies — or around 14 per cent — admitted they don't get the recommended travel vaccinations before jetting off overseas.
That means 3.5 million Aussies might be putting themselves at risk of contracting a preventable disease from around the world — and they could rack up a huge debt in the process.
That's because travel insurance won't pay out a claim for a disease that could have been prevented by immunisation.
In other words, those who skip their pre-flights jabs risk voiding their policy — which means if they do fall ill, they may have to foot the entire bill themselves.
According to the survey, men are more likely to avoid having a travel vaccine than women, while 7 per cent think they know more than health experts, dodging the needles because they "don't think they need them".
Meanwhile, 5 per cent of vaccination avoiders claim they do so out of fear of needles, while 4 per cent just don't want to have to fork out for immunisations.
Gen Y are the worst offenders, with 19 per cent claiming they don't get vaccinated before travelling, compared with just 10 per cent of baby boomers.
But the news isn't all bad — the survey also found 68 per cent believe travel vaccinations are crucial, and more of us are getting injections now compared with just over a year ago.
But getting vaccinated is clearly worth the hassle and expense, with more than 800 Aussies contracting tuberculosis so far in 2018, with 113 struck down by typhoid, 302 developing Hepatitis A and five infected with diphtheria.
Finder.com.au insurance expert Bessie Hassan said the findings were worrying — and that the travel insurance "loophole" could end up costing sick jetsetters a small fortune.
"Unvaccinated travellers could end up sick and incur extremely expensive medical bills while travelling," she said.
"Travel insurance won't pay out a claim for an illness that could have been prevented, so it's important to bear this in mind when preparing for a trip.
"Food and water borne diseases are common in many places overseas so it's better to be safe than sorry."
Ms Hassan said it was common for travellers to become ill while overseas, especially around food and water borne diseases.
"Outbreaks of these diseases still occur in countries with low vaccination rates," she said.
"It's crucial that Australians travelling overseas make an appointment to see their doctor before they go so they are not bringing home disease."