The HealthyTravel team wishes you a Merry Christmas and a happy 2026 with travels in good health.
The US CDC has updated the areas at risk for chikungunya. As of 16 December, there is a chikungunya travel health notice for outbreaks in:
Countries considered to have an elevated risk for chikungunya include:
*According to news (see under ‘Bolivia’) increased transmission is also seen in Bolivia.
In addition to optimal mosquito bite prevention, the Swiss ECTM recommendation include:
Chikungunya vaccination is recommended for:
Chikungunya vaccination may be considered for:
Of note:
Although global activity remains within expected seasonal ranges, early increases and higher activity than typical at this time of year have been observed in some regions.
Seasonal influenza viruses, including A(H3N2) viruses, continually evolve over time. Since August 2025, there has been a rapid increase of A(H3N2) J.2.4.1 alias K subclade viruses detected from several countries based on available genetic sequence data. These subclade K viruses have several changes from related A(H3N2) viruses. Current epidemiological data do not indicate an increase in disease severity, although this subclade marks a notable evolution in influenza A(H3N2) viruses. Early estimates suggest that the influenza vaccine continues to provide protection against hospital attendance in both children and adults, even though its effectiveness against clinical disease during the current season remains uncertain.
Media, citing local health authorities, report that the Departmental Health Service (Sedes) has issued a health alert following an active chikungunya outbreak in the Cochabamba tropics. Rubén Castillo, Head of Epidemiology, confirmed 100 cases, 81 of which are locally acquired, along with 40 suspected cases currently under investigation. The cases are primarily concentrated in the municipalities of Entre Ríos, Villa Tunari, and Puerto Villarroel. Authorities warned that transmission in the region continues to rise.
According to the European Center of Disease Control, chikungunya cases have been reported from six of nine departments with Santa Cruz to be the most affected one.
Optimal mosquito bite prevention 24/7, also for other mosquito-borne diseases.
Chikungunya vaccination may be considered for:
Of note:
Optimal mosquito protection 24/7, also in cities, see factsheet: Optimal mosquito and tick bite protection 24/7. This also protects you against other mosquito-borne diseases. Vaccination against chikungunya is not licensed in Switzerland.
For vaccination recommendations, see ECTM statement.
Practice regular hand hygiene.
Reminder: At risk person should be vaccinated against flu, RSV and SARS-Cov2 according to national guidelines. For Switzerland, see new FOPH Recommendation for RSV.
ECDC reports at least 193 Shigella sonnei infections in travelers returning from Cabo Verde in 2025, with most cases linked to all-inclusive resorts in Sal and Boa Vista. The outbreak strain shows resistance to trimethoprim with limited additional resistance markers.
Shigellosis outbreaks in Cape Verde have been reported in recent years, including among travelers.
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