The seasonal flu sickened an estimated 90 million young kids worldwide in 2008, landing a million in the hospital and killing 111,500, according to a new report.
The report -- based on a review of 43 studies involving more than 8 million children under 5 -- reveals the burden of flu among the world's weakest patients.
"Influenza is the second most common pathogen identified in children with [acute lower respiratory infections] and contributes substantially to the burden of hospitalization and mortality in young children," an international team of researchers reported Thursday in The Lancet. "Our estimates should inform public health policy and vaccine strategy, especially in developing countries."
The flu vaccine, which targets three common strains of the virus each season, is 59 percent effective at preventing infection. But people in developing countries, where 99 percent of flu-related deaths occur, often lack access.
"Given the level of serious illness that influenza causes, there is a real need to take our current vaccine -- with all its limitations -- and try and make it more available to the world's population," said Dr. William Schaffner, chair of preventive medicine at Vanderbilt University Medical Center. "And if we can make a better influenza vaccine, one that's more comprehensive, then there will be a huge imperative to deliver it to everyone."
Getting the flu shot to people in developing countries is complicated by cost, access and the need to keep the vaccine cool until the time of injection. And in countries plagued by malaria, tuberculosis and HIV, flu is lower on the list of priorities.
"Given that we have all those problems with vaccine production, distribution and implementation in developing countries, the next best thing is to focus on treating the complications of influenza," said Schaffner.
The flu virus inflames the tissues lining the passageway to the lungs, making them less capable of warding off bacteria. This can lead to pneumonia -- a lung infection that, left untreated, can be fatal.
"In patients who get admitted to hospital with bacterial pneumonia, you can use antibiotics to good effect," said Schaffner.
Children are especially vulnerable to the complications of flu. And through snotty noses and uncovered coughs, they can spread the virus like wildfire.
"They're the distribution franchise," said Schaffner. "If we reduce the transmission among children, we'll not only protect them but we will protect many older persons in our society because the virus won't get around as easily."
Among 115 children who died of flu-related causes in the U.S. last year, less than a quarter of them had received the flu vaccine, according to a September 2011 report from the U.S. Centers for Disease Control and Prevention.
The U.S. Centers for Disease Control and Prevention recommends that anyone older that 6 months get the flu shot. But less than half of eligible Americans got vaccinated last year -- a turnout driven down in part by misconceptions about the seriousness of the flu and the safety of vaccines, said Schaffner.
"There are also people that are grumpy that we don't have the perfect vaccine," he said. "It's good; not great."
But it's the best defense available. And people who choose not to get vaccinated -- despite plenty of vaccine and cheap (or free) access -- are missing an opportunity to safely protect themselves and others from the misery and risky complications of the flu, said Schaffner.
"If you haven't already, get vaccinated today," he said, adding that children under 8 need two shots the first season they get vaccinated. "Don't wait until tomorrow."