It’s flu season. Well, below the equator, it’s flu season. As we turn towards summer heat in the northern hemisphere, half of the globe has colder weather and more flu activity on the way. Just as we expanded Google Flu Trends to much of Europe last fall in advance of the winter flu season, we’re bringing Google Flu Trends to eight additional countries in the southern hemisphere where winter is approaching.
We now show national estimates (and a few regions too!) of flu activity for Argentina, Bolivia, Brazil, Chile, Paraguay, Peru, South Africa, and Uruguay, bringing our grand total of countries with Google Flu Trends estimates to 28. As flu affects millions every year, these estimates made in near real-time give health officials an additional early warning tool which can help them to respond more quickly to flu outbreaks. This can be especially important when people from many countries converge in one place, like in South Africa for the World Cup. South Africa is the first country we’re adding in Africa, and we hope Google Flu Trends will provide useful information for football fans and foes alike.
Several of the newly added countries are near the equator which means they won’t show a strong seasonal peak of flu activity. Brazil provides a neat example of how the flu season in a country becomes more pronounced as you are further away from the equator. In Ceará, a Brazilian province that is nearer to the equator, the Google Flu Trends estimates generally don’t show a strong peak. The chart below shows the current season curve as compared with last year’s curve:
You can, however, see a stronger peak emerge as you move further south, away from the equator. Rio Grande do Sul offers a fine example of this, again comparing the current season with last year:
Where more people are searching, our models will likely be more robust. We won’t be able to provide flu-related estimates if people aren’t searching for flu-related information online. In the U.S. we’ve given estimates that are more than 90% accurate as compared with the CDC’s ILINet data from which our model was built.
Upon annual review of a country’s model, we may release an updated model. Just as we updated the U.S. model one year after launching, today we’re also updating the Australia and New Zealand models. We’ve retrained these models with an additional year of surveillance data and they should better reflect current activity levels.
You can also see animated Google Flu Trends for the world in the Google Earth layer now also available on the website. This video visualizes flu activity over the last two years in North America and Europe:
Check out flu activity in your area and stay healthy!