The N = 10,000 network estimated in Section 3.3 for demonstrating the effectiveness of EGP-based intervention is obtained from 100 SIR epidemics. In subtropical countries, there is typically one flu season each year. So if the estimation is based solely on flu, it would take 100 years to obtain the estimated network. In Singapore, because of the tropical climate and high population density, there is anecdotal evidence that epidemics of mild respiratory infections come around every one or two months. Assuming there are six epidemics a year, the estimation above will take a much shorter time of 17 years in this country. The main risk of using multiple infections to shorten the estimation time is the increased number of wrong estimates when two epidemics overlap. However, this is a problem that cell phone and GPS co-location can help to solve as well.