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It seems like every time we hear about a flu outbreak, comparisons are made to the massive 1918 pandemic, which killed between 30 and 50 million people worldwide. But when that pandemic was unfolding, what did people compare it to?
As biologist Michelle Ziegler wrote on her blog last month, in 1918, doctors were warning that that year’s flu epidemic might be as bad as the 1889-1893 “Russian flu.” While estimates of the number of deaths caused by this pandemic are hard to come by, in a separate post Zeigler notes that it spread very quickly, taking just four months from the initial outbreak in St. Petersburg, Russia, to spread across the entire northern hemisphere.
The 1889 pandemic returned with a vengeance for four straight years, with the second year considerably more damaging than the first. While it was certainly not as devastating as the 1918 pandemic, it still has influence — one of the nicknames for the 1889 pandemic, “La Grippe,” remains a part of our lexicon today (for example, in Adelaide’s Lament in the show Guys and Dolls).
But even the 1889 pandemic wasn’t the first large-scale deadly flu epidemic. Ziegler cites an article by David Morens and colleagues, showing that flu pandemics have a recorded history that now spans 500 years. Although recent pandemics (including the 1918 flu and the 2009 H1N1 pandemic) have come from poultry and swine, for centuries the most common route to human infection was through horses, which is now much rarer. Why don’t we see much equine flu in humans any more? My guess is the rise of the automobile: Few people live around horses today, so transmission is rarer.
What can we learn from historical studies of flu pandemics? For starters, the second year of the 1889 pandemic was worse than the first. So even though we may feel safe because the 2009 H1N1 pandemic turned out to be mild, it’s important to remain vigilant. As neuroscience graduate student Daniel Ocampo Daza notes, vaccination is the best defense against influenza. Not only does it protect the individual who is vaccinated, it also prevents the disease from being transmitted.
And as pharmacist Scott Gavura blogged last month, few treatments are effective after you’ve already contracted the flu. Gavura took a detailed look at the evidence for one popular “treatment,” the herbal remedy echinacea. One team of experts in 2006 analyzed 16 different studies about echinacea’s effectiveness for treating colds and flu. None of the studies showed a statistically significant difference between treatment with echinacea and a placebo.
Doctors conducting a 2010 trial gave echinacea or a placebo to patients ranging in age 12 to 80 immediately after those patients first showed symptoms of a cold. As with the other studies, no significant difference was found. While, as Gavura admits, this still leaves open the possibility that echinacea might work with a different sample, for now it simply adds to the long list of studies measuring no effect. While some studies have focused on colds and others on flu, none has shown a significant benefit. In the absence of evidence demonstrating a positive result, there is little reason to take echinacea to treat or prevent colds or flu. The best way to treat the flu is to get vaccinated each year—that’s a preventative measure that has actually been shown to be effective.
Dave Munger is editor of ResearchBlogging.org, where you can find thousands of blog posts on this and myriad other topics. Each week, he writes about recent posts on peer-reviewed research from across the blogosphere. See previous Research Blogging columns »
Originally published January 12, 2011