Influenza Activity in the US: New CDC Data

Here are the latest influenza activity maps from the CDC; influenza activity continues to be widespread in the United States. The maps below illustrate how influenza activity has ramped up over the past few weeks (the most current map, including data for the week ending January 11, appears last). For orientation, states appearing in brown are states where there is widespread flu activity.

You can find up to date information on influenza from the CDC here. Here is a nice article that was just posted on CNN about influenza, as well. And remember: it's still not too late to get your flu shot!

Influenza in the US: Now Widespread

According to the CDC, influenza activity in the United States has now become widespread. The maps below demonstrate this (states appearing in brown have widespread flu activity; you can see how activity has ramped up across most of the middle of the country over the course of a single week).

This is shaping up to be at least a moderately severe influenza season; only time will tell how this season will compare to others. As this year's (Northern hemisphere) vaccine pretty closely matches the circulating flu strains detected to date, it is not too late to get a flu shot.

Update on Flu Activity in the United States

Detailed updates on influenza activity are produced weekly by the CDC and can be found here.

For the week ending on 12/22/12 here are the highlights (for the United States): 

1) 31 states reported widespread influenza activity (including my 'neck of the woods,' Virginia)

cdc.gov

2) There have been 16 pediatric deaths due to influenza since September 30, 2012. Overall the percentage of deaths due to influenza and pneumonia was below the "epidemic threshold" 

cdc.gov

3) Influenza A (H3N2) viruses have been most prominent, followed by influenza B; 2009 H1N1 (responsible for that season's pandemic) have been relatively rare

4) 312 infections with "variant" influenza viruses have been detected; these were mostly H3N2v. These viruses normally circulate in pigs and human infections have been attributed to prolonged contact with pigs at agricultural fairs; no sustained community spread of H3N2v has been detected

Influenza activity is now widespread in the US; this year's (Northern hemisphere) vaccine includes many of the circulating viral strains: it is not too late to get your flu shot! 

Where Is Flu Occurring? "Google" It!

Here is a link to a Los Angeles Times story that highlights work by Jeffrey Shaman and others on a new influenza prediction model using Google search data. These researchers created a new influenza tracking model that pulls data from the Google Flu Trends project and utilizes methodology from weather forecasting. They applied their model retrospectively to flu data from New York City from 2003-2008 and found that they were able to predict the peak of influenza activity over seven weeks before this actually occurred. 

This new study builds on work by Ginsberg and colleagues published in Nature in 2009 (full text available here). These authors created an influenza-like illness (ILI) surveillance model that utilized Google search data. This model correlated closely with ILI surveillance by the CDC, and predicted ILI nationally 1-2 weeks ahead of the CDC surveillance mechanism. 

The work by Shaman and colleagues illustrates that ILI surveillance models based on search engines such as Google can be refined using techniques from other disciplines (in this case weather forecasting). 

Other technologies such as Twitter and Facebook have also piqued interest as potential resources for disease surveillance, as well as for the real-time dissemination of information in the setting of disasters. 

For certain, influenza surveillance models utilizing internet search platforms such as Google are powerful tools, and as these models become more refined and are validated they will provide useful data that will give the medical and public health communities a real-time "heads up" when influenza activity is occurring. It is unclear how other technologies (such as Twitter and Facebook) can best be leveraged for disease surveillance and health communication, but these modalities also represent powerful potential tools.