Scientists hone computer model to predict flu outbreaks

There’s no shortage of experts monitoring influenza outbreaks around the globe.

The Centers for Disease Control and Prevention tracks flu activity in the U.S. year round and produces weekly flu activity reports between the peak months of October to May. Likewise, the World Health Organization gathers epidemiological surveillance data, and releases updates on outbreaks taking place anywhere, anytime.

Still, despite the monitoring and the annual push to administer flu vaccines, influenza still sickens millions of people around the world each year, leading to as many as 500,000 deaths annually.

But what if we were better at predicting — and preparing for — seasonal flu outbreaks?

That’s the impetus driving a team of researchers trying to show that it is possible to predict the timing and intensity of flu outbreaks in subtropical climates, such as Hong Kong, where flu seasons occur at irregular intervals throughout the year.

The group, which included scientists from Columbia University and the University of Hong Kong, has created a computer model to run simulations of an outbreak and predict its magnitude and peak, a study published Thursday in the journal PLOS Computational Biology said.

As a test case, the researchers gathering flu data from dozens of outpatient clinics and lab reports in Hong Kong between 1998 and 2013, then explored whether their system could accurately predict how outbreaks played out during those years. They said the program did remarkably well at predicting the peak of an outbreak weeks in advance.

That’s not to say it was perfect. Researchers said the accuracy of the predictions varied, depending on the strength of an outbreak and how far in advance they tried to make a prediction. In addition, forecasts for specific strains of influenza proved more reliable than those for overall epidemics, and it was easier to predict the peak and magnitude of an outbreak than exactly when it would begin or how long it might last.

Why does better prediction matter?

“These forecasts provide information at lead times that can be valuable for both the public and heath officials,” Jeffery Shaman, a Columbia environmental health science professor who last year helped develop a computer model to forecast the spread of the Ebola virus, said in an announcement of the findings. “Individuals may choose to get a flu vaccine to protect against infection, while officials can anticipate how many vaccines and other supplies are needed, as well as the number of clinicians and nurses needed.”

Being able to better predict flu outbreaks in a place like Hong Kong, which is a global crossroads and therefore an epicenter for influenza, eventually could help lessen the impact of the virus in other parts of the world.

Thursday’s study was funded in part by the National Institutes of Health, the U.S. Department of Homeland Security and the Hong Kong government. Researchers said they hope to continue refining their prediction models to account for complex factors, such as varying transmission factors among age groups and cross-immunity due to prior infection from similar influenza strains.

Predicting the timing and magnitude of outbreaks is just one piece of a complicated guessing game about the influenza virus. Another is the annual ritual of trying to select the strains to include in each year’s flu vaccine months ahead of time.

Last year, it didn’t go so well. Global health experts had hardly finished making their predictions when one of the strains they chose, a virulent type of H3N2 influenza, began to morph. It led to a particularly bad flu season.

“The virus is smarter than we are at this point. I don’t know of any disease that plagues us more. It’s very, very frustrating and a very inexact science,” Robert Daum a Chicago doctor who heads the Food and Drug Administration advisory committee that makes the U.S. recommendations, told The Post earlier this year, as the committee was about to meet to discuss strains to include in the coming season’s vaccines. “We do it with varying luck, and I think the luck is mostly the virus’ whim.”