Influenza Vaccine in Tropics and Subtropics

Patient vaccinated in Brazil

Over the last decade an increasing number of low and middle income countries situated in the tropics and subtropics have considered introducing or expanding seasonal influenza vaccination in their national immunization program.

Due to the complexities of seasonal influenza activity in tropics and subtropics e.g., multiple peaks and identifiable year-round activity, two challenging questions to these countries are when to vaccinate and which formulation (northern or southern hemisphere) to use.

The WHO Global Influenza Program recommends an evidence-based practical approach to group countries that share the same seasonality pattern and virus antigenic characteristics, into Influenza Vaccination Zones to address the country needs.