Queenslanders have again been warned about the dangers of measles after a man, who travelled to Vietnam, became the latest confirmed case of infection.

It brings the number of confirmed cases for 2019 to 13, one less than the total number of cases for 2018, a Queensland Health spokeswoman said on Wednesday.

It follows advice on Monday for people born after 1965, who have had only one dose of the MMR (measles, mumps and rubella) vaccine, to visit their doctor for a free booster.