"I've seen a lot of flu," said Dr. Arnold Werschky in Mill Valley. That includes last year's outbreak, and all its preventive complications. "Last year the shot didn't work because the guys who do the work came up with the wrong virus."
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Experts know that the flu virus follows winter between the northern and southern hemispheres.
"Every year we see peaks in January and it starts in December," said Dr. Matt Willis at Marin County Health. He tracks the progress of yearly outbreaks on a graph.
Will explained how each year, the Centers For Disease Control builds our flu vaccines based on what we see in Australia during their winter. Those vaccines are a best guess. Australia's Influenza was mild last year, but, "We're always worried there may be a new or novel strain we had not anticipated. It happened with Swine Flu in 2010.
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Or worse. A century ago, the avian Spanish Flu killed 100 million people---five percent of the world's human population. A similar virus could develop again.
"It is possible if a strain like the 1918 strain came out we would have similar morbidity and mortality," said Willis. We would see them despite a century of medical advances. "It takes weeks to develop such vaccines."
Best advice---get a shot sooner than later, and take your chances.
To learn about 2019's flu season, visit this guide from the CDC.
For more information on flu season, visit this page.