January 12, 2015|Categories: Analytics and Research
For the second consecutive week, national influenza-like illness (ILI) rates have declined, according to data from roughly one million patient visits on the athenahealth network. The ILI rate is 2.3% for the week ending Saturday, January 10, 2015, down from 3.4% for the week ending January 3, and 4.5% for the week ending December 27, 2014 (Figure 1). The pediatric ILI rate also fell during these two weeks, to 5.3%. That number is down from 6.3% for the week ending January 3 and 10.4% for the week prior to that.
These consecutive weeks of decline appear across census regions except for pediatric rates in the West, which climbed up slightly this past week (Figure 2). It is worth noting that this particular post-New Year’s resurgence of the pediatric rate occurred the previous two flu seasons as well.
Overall, it appears that the worst (the peak) of the flu season has passed, reinforced by consecutive steep declines in the South and Midwest. Given that the flu tends to migrate West, a region that typically has much lower ILI rates, we do not believe that the national ILI rate will rebound to levels near this season’s high (our friends at HealthMap also show similar declines).
Of course, this does not mean the season has ended, since current levels are still far above off-season rates. Given influenza’s widespread impact, we will continue to monitor ILI rates and report on any notable patterns or resurgence.
athenaResearch analyst Stewart Richardson generated the analysis for this report.