The picture of the swine flu outbreak within the past few months is becoming clearer as researchers are compiling more epidemiological data. Scientists working at the MRC center for Outbreak Analysis and Modeling have recently published their key findings in "Science". Among their key findings is that the fatality rate of the H1N1 strain found in Mexico is approximately 4 in 1000 (0.4%), which is similar to the fatality rate of the influenza strain that struck in 1957. Secondly, the rate of secondary infection per infected person (attack rate) is 1.2 to 1.6. Thirdly, in a confined study of the infection in the town of La Gloria, Mexico, researchers have determined that children are more likely to become infected than adults, suggesting that the adults have some degree of immunity; although this effect might be due to behavioral rather than biological differences. While the data is highly uncertain (with estimates of the people infected ranging from 6000 to 32,000 in Mexico alone), scientists are confident that the virus is spreading and is behaving very much like the early stages of a larger pandemic. Luckily, they also extrapolate from the data that this virus is no where nearly as deadly as the influenza strain of 1918.