Posted: June 29, 2009
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Article SummaryCanadian Press reporter Helen Branswell (the dean of the pandemic press corps) sent me an email asking my opinion on all the official statements that pandemic H1N1 is “mild” and that it attacks mostly people with “underlying health conditions.” I wrote back that both claims are accurate but misleading. When applied to a flu pandemic, “mild” doesn’t mean what we think it does, and an awful lot of people have “underlying health conditions.” And anyway, why were officials trying so hard to reassure the public, when the real problem was public complacency? Helen used only a little of my email in her article. This is my original email to her.

Is Swine Flu “Mild”? Are We Safe If
We Have No “Underlying Conditions”?

Helen Branswell’s Canadian Press article is also online.

You ask about two things that keep getting said about swine flu: that it’s usually mild, and that the people it kills usually have underlying medical conditions.

The “mildness” meme

The information that most swine flu cases are mild was crucial information in late April and early May, when the early news from Mexico suggested that swine flu might be very severe.  What “mild” meant then was fairly clear: The vast majority of cases weren’t fatal.  Swine flu wasn’t the public health catastrophe it had originally looked like it might be.

But now “mild” has become a meme more than an actual piece of information.  The question that is too seldom answered is: mild compared to what? 

Compared to bird flu, with its 61% fatality rate, swine flu is incredibly mild.  Compared to the 1918 pandemic, with its 2-3% fatality rate, swine flu is still very mild. 

And swine flu is mild compared to what it might turn into – compared to the possibility of a much more virulent second wave.  But the key message for this comparison shouldn’t be that swine flu is mild; the message is that swine flu could get a whole lot worse.  This is a message I’d like to see much more often: We need to get prepared in case it doesn’t stay as mild as it is so far.

Compared to the seasonal flu, which kills on average about one person in a thousand, swine flu isn’t especially mild.  Health officials can’t calculate a precise case fatality rate because they’re not trying to count all the cases – so they don’t have any denominator for the fraction.  But it’s looking like swine flu is roughly as deadly as the seasonal flu – about one death in a thousand cases.  And while seasonal flu deaths are overwhelmingly the elderly, swine flu deaths tend to be younger.

Like other flu pandemics, swine flu is expected to infect one-third to one-half of the population eventually (not counting any who get vaccinated, once there’s a vaccine).  When you focus on this pervasiveness to come, one death in every thousand cases doesn’t sound so mild anymore.  If you know two or three thousand people, someone you know will probably die of swine flu.  Several people you know will get seriously ill and need hospitalization.  And maybe a thousand people you know will go through a week or so of feeling really awful and being thoroughly incapable of doing much of anything, even taking care of themselves. 

Somehow, the word “mild” doesn’t conjure up all that illness in people’s minds.  Most people underestimate the seriousness of the flu to start with.  In normal, non-pandemic times, doctors are used to telling patients they probably don’t have the flu this time because they don’t feel rotten enough.  So when we’re told that swine flu is mild, we don’t think, “It will infect a half to a third of the world population and kill a few million people, mostly young people, before it’s over.”  We think, “It’s like having a bad cold.” 

Considering how hard public health professionals have to work to get the public to take influenza seriously enough – to bother getting vaccinated, for example – they’re not doing themselves any favors when they stress endlessly that swine flu is mild.  Assuming next year’s seasonal flu is equally serious, will they call that “mild” too? 

Bottom line: The mildness meme isn’t inaccurate, but it’s incomplete and therefore misleading.  It leaves people unprepared for what is almost certainly coming, lots of very sick friends and neighbors and a North American death toll in the tens of thousands; and for what might be coming, a more virulent strain of the same disease and a North American death toll in the hundreds of thousands or even the millions. 

The “underlying conditions” meme

Like the seasonal flu, swine flu often kills in combination with other medical conditions – asthma, diabetes, AIDS and other autoimmune disorders, pregnancy, etc.  In some cases the flu exacerbates another disease; in some cases the other disease weakens the system and makes it more vulnerable to flu.

This is obviously useful information.  It tells doctors that they should be especially attentive to patients with both the flu and one of the listed conditions.  It tells policymakers that they should prioritize people with the listed conditions when it comes to allocating scarce resources, such as antivirals and vaccines.  And it tells the rest of us that if we have one of the listed conditions, we should try even harder to avoid catching the flu, and should take it even more seriously if we catch it.

But like “mild,” “underlying conditions” has become a meme, repeated too often in ways that don’t necessarily convey the right meaning. 

What matters is that people with underlying conditions are especially vulnerable and need to be especially careful.  What people often hear, though, is that swine flu is no big deal because it’s usually not deadly except to people with underlying conditions.  That is, people hear it not as a warning but as an effort to reassure.

If people take this effort to reassure seriously, it will mislead them – because in fact swine flu has killed significant numbers of people with no underlying conditions at all.  But I suspect people are neither misled nor reassured by repeated news stories about people who died from swine flu plus some underlying condition.  More commonly, I suspect, we think of our own medical conditions, and of all the people we know with various medical conditions.  So if anything we feel a little alarmed. 

And perhaps we even feel a little offended.  The “underlying conditions” meme tries to draw a line between “us” (the healthy, who presumably have little to fear from swine flu) and “them” (those with underlying conditions, who might die … but after all they were sick already).  It sounds dismissive, and it backfires.  Too many of “us” feel like “them”; most people with listed conditions feel like they’re basically healthy.  So the news that they – we – are vulnerable to swine flu isn’t reassuring after all.

Why reassure?

To the extent that reassurance is the goal of these two memes, it is a pretty pointless goal.  At least in the U.S., public opinion polls show that concern about swine flu has declined from low to lower.  I assume the same is true in Canada.  In North America, swine flu panic is much rarer than swine flu deaths.  The problem isn’t panic or even excessive anxiety.  The problem is complacency, both about what’s going to happen and about what might happen.

Copyright © 2009 by Peter M. Sandman

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