What can flu history teach us about this year’s outbreak?

A Q&A with U-M medical historian Howard Markel, M.D., Ph.D.

New York policeman with flu mask - 1918

A New York City policeman wears a mask to avoid catching the 1918 flu.

The flu is back in force this year — especially a strain that attacks younger, healthier people and can cause serious, even life-threatening, illness.

Fortunately, this year’s vaccine can protect against it — unlike in 2009, when the same strain of the virus arrived after the vaccine was made.

And it’s a far better situation than back in 1918, when a slightly different strain killed 650,000 Americans.

Those two historic outbreaks can teach us a lot, says University of Michigan Medical historian and pediatrician Howard Markel, M.D., Ph.D. His team has studied flu history for the Centers for Disease Control and Prevention.

Q: What does studying past flu outbreaks teach us about flu? Isn’t this a virus we know a lot about already?
A: What’s really interesting is that as much as we know, we still don’t know that much about flu. We know more than we did in 1918 – but we still don’t have a lot of good information. We know basically how it’s transmitted – through droplets, coughs — and how long it stays on a surfaces, which is about 24 to 48 hours. But we’re not entirely certain. That’s why flu still deserves a lot of research.

Q: Why are some years so bad and others, not so much?
A: Flu tends to travel in a very erratic and strange ways through a population, because it’s so easily transmitted and because people travel. But we don’t know why, year to year, some flu seasons are very severe – or why in some people it’s more severe, other than the fact that it tends to strike people with underlying illness harder. It’s amazing how little we still know.

Q: This year’s main strain of flu is called H1N1. What does that name mean?
A: Flu is a virus, and the H and N stand for two molecules that form parts of the virus: hemagglutinin and neuraminidase. The numbers are for a particular type of each molecule. They mix and match as the flu travels, so one year H1N1 is the main strain, then H5N1 another year. The real million dollar question is: how much experience does most the population have with that predominant strain, from past years? That tells us how well individuals will deal with it if they are infected, and helps us produce a vaccine for the U.S. six or more months in advance using data from the strain that’s going around South America. But it’s all still a guesstimate.

Philadelphia ambulance  - 1918 flu

An ambulance pulls up to a Philadelphia Girls Club that was converted to a hospital during the 1918 flu epidemic.

Q: What other things can flu history tell us?
A: One thing that history has taught us nicely is how important it is not to hang around in crowds, and for authorities to temporarily close schools, in really severe, deadly outbreaks. In our 2009 flu studies, we see signs that school closures did tend to stem the spread. But the minute the kids begin to congregate again, it comes back. School closures can be a stopgap until get kids vaccinated, and may be most important in special schools for kids with autism or other conditions. So thinking about this year, it will be interesting to look at the impact of the major snowstorm and cold temperatures that struck just as students were preparing to return to school early this year – even those three days of school closure may have had an impact.


Q: What can we do to protect ourselves?

Men line up for the 1918 flu vaccine

The 1918 flu vaccine wasn’t effective against the H1N1 strain of the virus that killed hundreds of thousands. But this year’s flu vaccine is effective against the strain that’s going around.

A: Everybody from age 0 to 100 has to take precautions this time of year. That’s means a lot of handwashing with Purell or good old-fashioned soap and water. If you are sick, stay home for 24 to 48 hours, because we don’t know exactly when people are contagious. With flu, it’s likely that you can spread it as long as you have a fever and other symptoms. You can even spread it early in the course of the illness, when you first start coughing, as the virus is incubating in you. But the more symptomatic you are, the more the virus is shedding – that’s when you have the very bad wracking cough, fever and chills, aches and pains. The other thing to remember is that when you get vaccinated, or keep yourself out of circulation when you’re sick, you’re not just protecting yourself. You’re protecting others, including the most vulnerable – and being a responsible part of the community.


Q: So if this year’s flu is H1N1,  just like 2009’s bad flu and 1918’s killer flu, should we be extra concerned?

New York City typist, 1918

A typist in New York City wears a mask to avoid catching the 1918 flu.

A: Although this year’s flu is mainly a similar strain, nothing has ever looked like the H1N1 of 1918, and this year isn’t going to either. It was so virulent – dangerous — because very few humans’ immune systems had experience with it. This year, everyone has had it or been vaccinated once or more against it in the past.

Though we can learn a lot from 1918, we have never again seen anything like it – it’s the greatest epidemic ever. We were worried in 2009, because it looked initially as if was very deadly and people didn’t have experience with it. In early 2009, we didn’t know the extent of non-deadly cases, so the case fatality rate seemed very high. It also came out of a place no one was expecting, Mexico, when the flu experts had mostly been focused on Asia and the H5N1 strain. The 2009 flu was a pandemic, meaning it spread everywhere. And it affected young children and younger adults with underlying illnesses, including obesity, more severely than other flu strains. But on the whole it didn’t turn out as badly as first feared. Still, it did cause deaths, and when a child or younger adult dies, there’s understandably more concern. This year, there have definitely been severe cases in younger and middle-aged adults, and we’re getting them here at U-M because we’re well-equipped to take care of the worst of the worst. But fortunately this year, the regular seasonal flu vaccine includes protection against H1N1, unlike in 2009.

Q: What else can the 2009 outbreak teach us? A: We’re preparing to publish data from our research, so we’ll be able to say more soon. But in general we were struck by the role of politics and social factors, as well as public health data, when it came to closing schools. We’ll continue to study data from that year, because it’s not a matter of if, it’s a matter of when, the next flu pandemic will come.

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All images in this article come from the Influenza Archive.

Simpson Memorial InstituteThe U-M Center for the History of Medicine, part of the U-M Medical School, conducts research and collaborations that place contemporary medical dilemmas in context with past events to help inform public health and medical policies. It also serves as consulting historians to the Medical School, and fosters appreciation of the medical humanities among U-M medical students. It is housed in the Simpson Memorial Institute, a 1926 building on the U-M medical campus shown at left.


new_logos_180x1806For more than 160 years, the University of Michigan Health System has been a national leader in advanced patient care, innovative research to improve human health and comprehensive education of physicians and medical scientists. The three U-M hospitals have been recognized numerous times for excellence in patient care, including a #1 ranking in Michigan and national rankings in many specialty areas by U.S. News & World Report.