Risk assessment guidelines for infectious diseases transmitted on aircraft (RAGIDA): Influenza

This technical report provides options for contact tracing approaches related to possible transmission of influenza viruses on aircraft. It is targeted at decision-makers faced with the choice of whether to contact-trace air travellers and crew that were potentially exposed to influenza viruses during a flight, and covers the following:
 

• Seasonal influenza
• Novel influenza virus with pandemic potential, or seasonal influenza virus with increased virulence
• Influenza virus with zoonotic potential, such as avian or swine influenza

 
Contact tracing of passengers or crew possibly exposed to an influenza virus on-board an aircraft can have a number of objectives:
 

• to slow down the spread of the virus upon introduction into a country/region
• to facilitate timely diagnosis and treatment, for example, to administer post-exposure prophylaxis
• to allow implementation of other control measures like isolation
• to study the characteristics of the virus or assess the epidemiologic situation

 
When assessing the risk of infection on-board an aircraft, criteria such as the infectivity of the index case, the time since the flight occurred, evidence of transmission in the country of departure and the country of destination, the scale and prioritisation of contact tracing are all important considerations to take into account. 
 
The document proposes practical algorithms that cover these considerations and assist in making decisions if contact tracing should be pursued and what should its extent be in specific cases.
 
The proposed contract tracing approach is based on evidence found in scientific literature, combined with the knowledge of a disease-specific expert panel.