Researchers have found that the chickenpox virus may actually be a seasonal disease, with more cases reported in the spring, according to a study published today in the Proceedings of the National Academy of Sciences.
To identify chickenpox rates, the researchers turned to an unconventional source: Google Trends. The search engine has actually successfully been used by researchers before to estimate and examine influenza rates. For this study, researchers wanted to see if chickenpox was a seasonal disease in the same way the common cold or the flu is.
They looked at Google search data from 36 countries over an 11-year period and then validated that data with information from published clinical cases. Researchers found that the virus appears to peak in the spring globally, though in countries where vaccines are used the association was much weaker.
The results of the study were somewhat limited since the only countries that were studied were in temperate regions where there was internet access and the population had enough education and literacy to search for information about the disease online.
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However, Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center who was not involved in this study, said the findings may be especially useful in countries where the chickenpox vaccine is not common and where the rate of the disease is not tracked.
"Data can instruct a ministry of health, where they don’t have any idea about chickenpox [rates]," Schaffner told ABC News. He said it was also interesting to see how chickenpox searches were different in countries where vaccines were readily available.
"In countries where we immunize routinely, the seasonality is much more muted and the inquiries themselves aren’t about disease and symptoms and treatment [but] about vaccines," he said, noting that those people doing online searches may have heard about a chickenpox infection in their community and become concerned their child was exposed.
Kevin Bakker, lead author of the study and a graduate student in Ecology and Evolutionary Biology at the University of Michigan, explained that he wanted to use the Google data after seeing how google searches appeared to match known seasonal peaks for childhood infectious diseases.
"I think digital epidemiology, which is using Google trends or Twitter trends ... is a complement to clinical data," said Bakker, explaining the drawback of getting traditional reported clinical data is that it takes a long time until it reaches the U.S. Centers for Disease Control and Prevention.
"You take your child to the doctor and the doctor sends the case report to state health officials and the CDC compiles it all," Bakker said. "If I go to Google Trends you can see the top trends in data anywhere in the world."
He emphasized Google data is being used as a supplement to traditional clinical data, which he and his co-authors used to verify the Google data.
Dr. Amy Edwards, pediatric infectious disease specialist at University Hospitals Rainbow Babies & Children's Hospital, said more research is needed to verify the findings but that Google data may become extremely helpful in the future as medical officials plan where to allocate resources during an outbreak of a particular disease.
"It has the potential to be extremely interesting particularly in unreported and under-reported diseases," Edwards said, explaining that information about the start of a flu outbreak can help medical staff start to screen people earlier for the virus and take protective measures.