Hand-hygiene mitigation strategies against global disease spreading through the air transportation network

Christos Nicolaides; Demetris Avraam; Luis Cueto-Felgueroso; Marta C. González; Ruben Juanes

where T i is the total outgoing traffic from airport i, k i is the number of connections of i (i.e. the degree of node i in the network), and ∑ k i i=1 w i j d i j is the effective length of all links of i which is the weighted sum of the actual distances d i j between i and j nodes. The weights w i j are the fractions of passengers traveling from i to j. The susceptibility of airport i is calculated using the conventional SIR simulations as the weighted average fraction of infected individuals that arrive at i over all the seeding scenarios considered in the SIR model described above. Using the above combined metric (susceptibility × strength), we identify the ten 'key' airports of the world air transportation network as being the LHR, LAX, JFK, CDG, DXB, FRA, HKG, PEK, SFO and AMS. For the intervention scenario (ii), we identify ten 'key' airports for each source of the disease, by multiplying the airport strength by the source-dependent susceptibility. The source-dependent susceptibility of airport i for the seeding of the disease at airport j is calculated as the fraction of infected individuals that arrive at i when the disease is initiated at airport j. Therefore, for this intervention scenario, knowledge of the source of the disease is required and for different sources of the disease we have different sets of 'key' airports (see Figure 4 ). Finally, for the intervention scenario (iii), since we increase the hand washing engagement rate only at the source of the disease, prior knowledge of the source is required.