Cast your mind back to about this time a year ago. A novel strain of flu, influenza A (H7N9), had emerged in China, in the provinces around Shanghai. International health authorities were deeply concerned, because any new strain of flu bears careful watching — and also because, on the 10th anniversary of the SARS epidemic, no one knew how candid China would be about its cases.
By the time peak season for flu ended in China, there had been 132 cases and 37 deaths from that newest flu strain. But, confounding expectations, the Chinese government was notably open about the new disease’s occurrence, and scientists worldwide were able to ramp up to study it. Still, no one could say whether that flu would be the one to make the always-feared leap to a pandemic strain that might sweep the globe. As with other, earlier, worrisome strains of flu, science could only wait and see whether it might return.
And now it has.