It’s hard to get a handle on swine-flu numbers — on who has H1N1 and where. We’ve listed here some data resources (including those from CDC and Flu.gov), but they don’t show an exact picture of the pandemic.
One basic limitation of the data stems from the way they’re reported. Back in July, the US government discontinued “official reporting of individual cases of confirmed and probable novel H1N1 infection.” The reason? The CDC explains that “as novel H1N1 flu became more widespread, individual case counts became an increasingly inaccurate representation of the true burden of disease.” It argues that some infected people never visit a doctor, and even those who do aren’t necessarily tested. So now CDC surveys H1N1 trends in the same routine way it does seasonal flu — but it doesn’t count individual cases. You can find the CDC’s reporting guidelines here.
This AP article gives a good overview of the reality and problems of H1N1 data reporting. It explains the CDC’s surveillance system this way:
The CDC has nine ways of monitoring influenza. Some focus on people who die from flu-like illness — one tracking deaths of children, another counting pneumonia and flu deaths of all ages in 122 cities.
Other systems gather flu-testing information from labs across the country. And some rely on reports of flu-like illness from hospital emergency departments and from estimates from state and territorial health officials.
Those systems combine to give a good general picture of whether more or fewer people are going to the doctor with flu, and how often lab samples are showing swine flu as compared to other respiratory bugs, health officials say.
On the international front, WHO also declared in July that reporting of individual swine-flu cases was no longer realistic or essential.
So where does this leave you — stations, reporters, producers — in offering the numbers to your audience? In this third excerpt from the FluPortal webinar, NPR’s “stats genius” Robert Benincasa explains that NPR and CDC are sitting down together to create an online, Adobe Flash-based “visualization” that you’ll be able to put on your website. Benincasa says it will draw from the CDC data series mentioned in the AP excerpt above — which don’t necessarily separate H1N1 data from other influenza data. It will update itself automatically whenever the CDC releases new numbers.
This NPR tool will focus on national-level data, so Benincasa warns that for community- or county-level data, your local health authorities will remain your best source.
