It's too soon to talk about the pandemic in the past tense

Suddenly, there seems to be a public perception that the H1N1 swine flu pandemic is over. At least, that's the sense I get within the U.S. public.

It's thankfully true that instead of officially having "widespread" flu activity nationwide in the U.S., only four states reported "widespread" activity last week, down from seven the week before. However, outpatient medical visits for flu-like illness, which were at the national baseline the previous week, edged back above that level, according to the CDC. Also, deaths due to pneumonia and flu climbed back above the epidemic threshold.

But just because flu activity may have declined where you live, don't think the pandemic is over. It isn't.

The H1N1 flu pandemic probably began less than one year ago, not coming to the attention of the WHO until only nine months ago (April-May). While the second wave now is declining in the U.S. and most of the rest of the Northern Hemisphere, flu activity is intense in Central and Eastern Europe, northern India, Nepal, and Sri Lanka, according to the World Health Organization's weekly H1N1 update. Pandemic flu activity ebbs and flows from location to location (and back again) until the global community achieves "herd immunity" to the new flu strain via exposure or vaccination. I doubt we're there so soon.

The apparent shift in attitude about the presence and threat of the pandemic really got my attention when I read a January 1 article by Donald McNeil of the New York Times. Mr. McNeil has been a leading reporter on the pandemic. So I was surprised to find his January 1 article is at odds with itself. His opening sentence says "it is too early to write the obituary for swine flu," yet the article broadly speaks of the pandemic in the past tense. And Mr. McNeil states that the pandemic "seems unlikely to reach even the lower end of a forecast of 30,000 to 90,000 deaths" and "It is now clear that this is the least lethal modern pandemic." Yet, the fact is (as I'm sure Mr. McNeil would readily agree), no one knows how this pandemic will play out - whether it is waning for good or whether there will be additional waves/outbreaks and, if so, how severe those will be and how well our health care systems handle the load. Flu viruses are noted for their tendency to mutate; yet no one knows how the pandemic H1N1 virus might change in coming weeks/months. No one knows these things. No one.

Also, there's room to debate whether government reactions have been the right steps. For example, undoubtedly closing schools would have delayed and probably reduced the peak outbreaks. It had been broadly predicted that the number of flu cases would shoot up as soon as U.S. schools and universities opened in the fall ... and that's exactly what happened. Opening schools ignored a key mitigating philosophy of pandemic planning: delay the spread. Delaying the spread of flu not only delays the caseload, it lowers the peak caseload. This delay buys time for vaccine production and other responses and the lower peak reduces the strain on health care systems. Opening schools had the opposite effect: it caused a more rapid spread and a higher spike in cases. I suspect opening schools was not a public health decision as much as it was a "political" decision driven by two factors: (1) school systems had not adequately prepared for a pandemic (e.g., they had no alternative plans for teaching) and (2) in an era where both parents work and/or the household has a single parent, schools were needed for babysitting or childcare services and as feeding stations. So the flu spread quickly among school children.

This New York Times article was surprising because Mr. McNeil well knows the characteristics of flu pandemics. In an article on Nov. 21 about the apparent peak in current pandemic flu activity, Mr. McNeil reported:

Epidemiologists expected a peak about now, because flu waves typically last six to eight weeks.

...and...

Dr. Anne Schuchat, the director of immunization and respiratory diseases at the C.D.C., chose her words carefully, saying: "I wish I knew if we had hit the peak. Even if a peak has occurred, half the people who are going to get sick haven't gotten sick yet."

That was just six weeks ago.

I believe the emphasis should be on Mr. McNeil's opening statement in yesterday's article: "it is too early to write the obituary for swine flu." It is not a past event, but an ongoing one. Remain prepared.