One is a viral illness responsible for an estimated 35,000 deaths every year. The other is a potentially deadly superbug, a horrifying legacy of antibiotic overuse that is now resistant to almost every treatment today's doctors can throw at it.
Even on their own, infection with either influenza or methicillin-resistant Staphylococcus aureus (MRSA) can lead to a grave situation. But now, health officials are keeping an eye out for an even more harrowing threat -- simultaneous infection with both diseases. And they say that, in children at least, these cases of co-incident infection appear to be on the rise.
So far, what the U.S. Centers for Disease Control and Prevention has learned about the potential link between flu and MRSA in young patients is disturbing.
According to an official health advisory issued Jan. 30, between Oct. 1, 2006, and Sept. 30, 2007, the agency received a total of 73 reports of child deaths due to influenza. In 22 of these cases, the children were also infected with some form of the staph bug, mostly MRSA.
This compares with only three such cases of co-infection during the same period in 2005 and 2006, and just one such case identified in 2004-2005.
And on Friday, the Boston Globe reported that Massachusetts health officials have linked MRSA to two recent deaths in children from the flu, renewing concerns over such a surge.
It is not the first time that viral and bacterial infections have gone hand-in-hand, notes Dr. Jonathan C. Weissler, chief of medicine at University of Texas Southwestern University Hospitals in Dallas.
"It is well known that community-acquired staph pneumonia is much more common in patients who have influenza," he says. "This has not changed."
But when it does happen, the results can be disastrous. Infectious disease experts say spikes in this kind of co-incidence of influenza and drug-resistant bugs have happened in the past, with devastating results even for many healthy individuals.
"The association of influenza viral infection disrupting the mucosa to permit secondary bacterial infection is not new," says Dr. Jerome Klein, professor of pediatrics at Boston University School of Medicine. "This is what happened in the influenza pandemic in 1957, which was co-incident with a pandemic of multidrug resistant staphylococcal infections. Not only were the elderly and immunocompromised prone to the combination, but otherwise healthy individuals were felled with substantial morbidity and mortality."
"Thus, now when children -- and maybe adults also -- get influenza that is complicated by pneumonia, the bacterial cause of the pneumonia will likely be MRSA," says Dr. William Schaffner, professor and chairman of preventive medicine at the Vanderbilt University School of Medicine. "Thus, we have a new phenomenon that can cause serious, life-threatening disease and is more difficult to treat."
Contracting both the flu and MRSA at the same time is far more than simple coincidence, scientists believe. Rather, they suspect that the damage inflicted on the lungs and airways by the flu virus allows MRSA germs to sneak into vulnerable tissues and gain a foothold.
The timing of concerns over the links between flu and MRSA come at a time when pandemic fears are growing and reports of nonhospital superbug infections are on the rise.
"The public health groups in the state and the CDC are concerned about a confluence as 'the perfect storm,' a virulent influenzal pandemic -- for example, bird flu, SARS or [another viral illness] occurring at the same time as the increasing incidence of MRSA," says Klein.
Schaffner says the key to heading off the dangerous partnership between influenza and MRSA is to go on the attack against the flu with increased vaccination rates.
It is a task that is easier said than done. Schaffner notes that only about one-third of children actually receive the flu vaccine during a given season. Part of the reason behind this low turnout could be the number of groups that actively discourage parents from having their children vaccinated against the flu. These groups claim that these vaccines -- primarily, the forms of the vaccine that contain thimerosal -- are a primary cause of autism in children.
One group, known as SafeMinds, provides a printable brochure on its Web site titled "Help Spread the Word About the Flu Vaccine." The group encourages supporters to leave the brochure in their doctors' offices and other locations.
On the other side of the vaccination equation, current CDC recommendations do little to bolster flu vaccination among kids, as they urge vaccination primarily of children 6 months to 5 years old, and others "if feasible."
But this could change soon. Schaffner says that by the 2008-2009 flu season, the agency will change its guidelines to recommend that everyone under the age of 19 receive the flu vaccine.
Additionally, he hopes that parents and pediatricians will take immunization recommendations more seriously as additional information about MRSA and influenza become public.
"This strengthens even more the rationale for vaccinating all children against influenza each year," he says. "If you prevent the initial influenza infection, you also prevent the dire complication of MRSA pneumonia. Thus, vaccinating all children against influenza is a public health program with a double benefit -- what could be better than that?"
Dr. Diane Kang contributed to this report.