If you haven't gone for a flu shot yet, you may want to hurry—the season of sickness is already upon us. The CDC's weekly flu tracker notes a wider geographic spread of the illness across the US compared with this time of year in years past. Popular Science also reports, based on baseline numbers, flu season kicked off during Thanksgiving week, a few weeks ahead of the past two flu seasons. Per Today, the CDC's numbers also indicate four states are reporting widespread influenza activity (no states reported such in 2016 at this time). And news from Australia, which is hit with its flu season months before ours (serving as a gauge of sorts for what we may expect), isn't promising, with a record number of cases, hospitalizations, and deaths. As it can take weeks for the flu shot to kick in, this all underscores the importance of people getting their shots ASAP, experts say.
Adding to the unpredictability of how we'll fare with the flu is that vaccines "are usually only about 40% to 60% effective in the best of years," Martin Hirsch, EIC of the Journal of Infectious Diseases, tells USA Today. That's what makes the Australia news worrisome, as the main flu strain there was H3N2, the vaccine there was only about 10% effective against that strain, and the H3N2 portion of that vaccine is the same one we'll use. But experts say it's still impossible to tell where we'll end up: The US may be mainly hit by strains other than H3N2, for example. Either way, Hirsch and others still recommend getting the shot, as it could still mitigate symptoms and keep you out of the hospital if you do get the flu. The vaccine could also offer protection against other strains, and, thanks to herd immunity, could help protect more vulnerable people like the elderly. (Read more influenza stories.)