International sporting events are another example of increased disease risk due to mass gathering. With Japan hosting the Rugby World Cup in 2019 and the Olympics and Paralympics in 2020, researchers have assessed the vaccine-preventable disease (VPD) epidemiology there.11

Most VPDs present a low risk for travellers to Japan, but “due to the epidemiology of rubella, mumps and influenza in Japan, these diseases should be prioritized for pre-travel advice.” Measles and invasive meningococcal disease risk is also generally low, but as outbreaks occur regularly via international transmission, vaccination status should be considered.

Less familiar to Europeans is Japanese encephalitis, a mosquito-borne viral disease endemic in many Asian countries. Japan is considered a high-incidence country, although routine vaccination programmes have controlled levels to an incidence of 0.003 per 100,000 population. As such, travellers intending to visit western Japan, especially non-urban areas, should consider Japanese encephalitis vaccination as well as mosquito-bite prevention.11,12