Costa Rica has been struck with a case of measles for the first time in over five years after an unvaccinated French boy fell sick with the disease while visiting the country on holiday, according to Costa Rica’s Ministry of Health.

The 5-year-old boy arrived in the country on February 18 along with his parents. He was taken to hospital after displaying measles-like symptoms and is currently being kept under “strict isolation measures” at Monseñor Sanabria Hospital in Puntarenas. The child has since tested positive for measles and local health authorities are working hard to track down everyone who might have been in contact with the family, including people who boarded the same France Air flight, reports The Costa Rica Star.

The last case of measles reported in Costa Rica was in 2014, which was also brought into the country from the outside. The last case to originate in the country was in 2006.

Measles is a highly contagious viral disease that can be spread through coughs and sneezes. Typical symptoms include a fever, coughing, red eyes, and a distinctive skin rash. However, this potentially deadly disease can be prevented by receiving two doses of a measles-containing vaccine.

Fortunately, Costa Rica has a good public health system and a robust vaccination program that issues the recommended two doses of the vaccine. In 2017, at least 96 percent of the population had received the first dose of measles vaccine and 93 percent had received the second dose, according to World Health Organization statistics.

“Our country enjoys very good vaccination coverage in general, however, it is always important, in order to avoid particular cases and their possible complications, that those in charge of minors ensure that children have the complete vaccination scheme,” Costa Rica’s Ministry of Health said in an announcement.

It’s unclear why the boy was not vaccinated, but it’s worth remembering that some people cannot receive vaccinations on valid medical grounds, such as having a compromised immune system.

That said, Europe has recently seen a surge in reported measles cases due to under-vaccination. The reason behind this under-vaccination is not crystal clear, however, it is regularly associated with a resurgence in skepticism towards vaccinations.

This skepticism mainly rests on the erroneous fear that the measles, mumps, and rubella (MMR) vaccine is linked to autism. While science has wholeheartedly disproven and discredited any such link time and time again, the anti-vaxxer movement has gained a foothold in the age of social media. Sympathetic politicians have also bolstered the cause, such as Italy’s current government that looked to remove mandatory vaccination for schoolchildren claiming they were “useless, and in many cases dangerous”.

The results of under-vaccination are all too clear: Europe saw 82,596 new cases of measles in 2018, three times as many as 2017. Outside of Europe, the picture is not much better, with measles cases doubling globally last year.