Who was hit hardest last flu season?

Our Mission

On average, 5% to 20% of the U.S. population gets the flu each year, but not all age groups are affected equally. Compiling fever readings collected by Kinsa's nationwide 'sensor network' of Smart Thermometers - the first device families turn to when illness strikes - proves what many may already suspect.

School aged children hit hardest

It’s common knowledge that there is a link between schools and the spread of germs. It seems obvious – you put a susceptible population with developing immune systems in close quarters, toss in some germs, and you have a petri dish for cold and flu.

Last year’s Kinsa data shows school aged children had similarly timed peaks, and grossly (no pun intended) surpassed toddlers, college-aged students, and adults with the highest illness percentage (fevers/sample population). 

What this means for prevention: The flu costs a conservative $10.4 billion dollars per year in the U.S. alone. Effectively targeting schools with proper preventative tactics can lower the spread across all age ranges, increasing workforce productivity, but this solution isn’t so simple. With 98,300 active public schools, it’s very difficult to provide adequate resources across the board. By understanding spread, we can select not only which populations to target in a given year (schools, senior homes, etc) but when and where as well.

Elementary aged children show first seasonal spike

While school aged children had the highest illness % overall, younger children (elementary aged) saw a rise in illness % weeks earlier than those in the 10-19 age bracket (middle/high school).

What this means for prevention: Instead of targeting all populations equally, it would be more effective to target specific groups (age, school-level, geography) that appear to be the catalysts in a given season, before these high-risk populations spread to those close by.

With the advent of technologies like Kinsa, we can now proactively monitor at-risk populations in real-time, and provide these populations with solutions in their moment of need.

The need for real-time surveillance

Electronic medical claims are currently relied on to give us an overview of emerging trends. Unfortunately, this data may be flawed by “selection bias” with research suggesting a large portion of those with a common illness such as influenza never see a doctor or get a prescription, relying solely on OTC meds. Another issue is the length of time it takes for an agency such as the Centers for Disease Control and Prevention (CDC) to gather and process the data, relying on local jurisdictions to send reports. For an infectious disease such as influenza, early detection and response is vital. For an interesting take on the keys to preventing the next flu pandemic, see Dr. Sanjay Gupta’s article “The big one is coming, and it's going to be a flu pandemic.


  • Children in primary school and secondary school led all other age brackets in illness percentage.
  • Ages 5-9 had a significant jump in illness % before other school-aged children.

With improved surveillance comes new insights. I’ll be posting these insights here and on our Kinsa Insights blog, for those interested in following cold and flu trends.


Download: Baby's First Year Weekly Health Chart