There are a number of possible public health measures that may be used to stop or slow down the spread. Border control has been extensively discussed in this context to delay the international spread of influenza. However, in order to achieve a significant delay, more than 99% of air travel would have to be stopped [3] . As has been shown for SARS, entry screening methods are unlikely to detect more than 10% of imported infections and the positive predictive value of temperature screening is low especially at the beginning of a pandemic [4, 5] . It is therefore inevitable that importation occurs. For the management of imported cases, other measures may be used and include contact tracing, isolation and quarantine, as well as post exposure prophylaxis. It is unclear; however, which public health strategy could be effective in preventing the spill-over from imported cases and slow-down the transmission within the general population. Even less clear is how long these measures should be maintained, particularly once that domestic transmission has started.