. >> back in march, 5-year-old edgar hernandez was apparently the first human infected.as now spread from mexico to 120 countries. it's spreading in the summertime in the northern hemisphere which isn't supposed to happen. it's spreading because h1n1 is totally immune -- a totally new strain. no one has had it before, so no one has built up an immunity. >> every single contact of an infected person is likely to lead to transmission. >> here in london, khloe buckley, an otherwise healthy 6-year-old girl died two days after falling sick. initially, doctors said she just had strep throat. parents across britain panicked, khloe's school closed early for the summer vacation. come the fall, the temperature will drop. humidity will rise and we'll be back huddled indoors, breathing on each other. >> then it will start to take off with a vengeance when you have the reassembly of kids to schools. >> britain and the u.s. right now have similar infection rates and britain is now expecting 100,000 new cases every day. come september. we are already being told to stay away from the do