State, CDC track link in child flu deaths
Two in Mass. also had fast-moving infection
State and federal disease investigators are tracking a disturbing increase in deaths among children stricken simultaneously with the flu and a hard-to-treat, fast-moving bacterial germ.
Massachusetts health authorities have linked two recent childhood flu deaths to a germ called methicillin-resistant staphylococcus aureus, known as MRSA, which evades the most common antibiotics. Nationally, of the 74 children known to have died from the flu in the United States in 2006-2007, 22 also had staph infections, most of which were MRSA.
Authorities at the US Centers for Disease Control and Prevention are so concerned by the phenomenon that next flu season they will activate a monitoring network at five sites - including one in Rochester, N.Y. - to hunt for patients co-infected with flu and MRSA. Specialists said that information and other findings could guide doctors to determine how to quickly intervene, preventing flu-MRSA cases from turning fatal.
Originally confined to hospital wards where it could find easy targets among the seriously ill, MRSA began migrating more broadly a decade ago, establishing a foothold across the United States and endangering otherwise healthy children and adults.
Scientists suspect that influenza is playing a deadly role in MRSA cases: The flu virus acts almost like a doorman for the bacterium, causing changes in the respiratory tract that allow the lethal germ to sneak in and start a devastating cascade of complications.
"I've been surprised by this phenomenon of MRSA with flu, which has been really quite shocking this winter," said Dr. Kenneth McIntosh, an infectious disease specialist at Children's Hospital Boston, who said he believes there were other children with both flu and MRSA who survived. "I think everybody's concerned about it. What to do about it is not clear."
So far, cases have been identified principally in children, which probably says more about the rarity of severe illness in youngsters than about the habits of the germs, specialists said.
Adults who die from the flu tend to be afflicted with an array of underlying medical problems, making it more difficult to identify all the factors contributing to their death.
Still, the tracking network being established next year will endeavor to more broadly gauge the impact of flu and MRSA on both children and adults.
"For whatever reason, it does seem that people who are co-infected are more likely to die than people who are just infected with staph aureus," said Dr. Alex Kallen, an Epidemic Intelligence Service officer at the CDC in Atlanta.
Researchers have known for the better part of a century that flu patients are prone to developing staph infections that can bring on pneumonia, a finding that became evident during the monumental flu epidemic that swept the world in 1918.
MRSA is a particularly virulent strain of staph that is a legacy of overusing antibiotics. When patients don't take their full course of antibiotics or they are given antibacterial medicine when they don't really need it, that allows hardier germs to survive, thrive, and acquire the genetic ability to outwit first-line antibiotics.
The germs find ready reservoirs in the noses and throats of healthy people. Most of the time, the bacteria just sit there, causing no obvious harm.
"Being a carrier of MRSA has increased a lot, especially among school-aged kids," said Lyn Finelli, chief of influenza surveillance at the CDC. "And being colonized may put them at risk for a severe staph aureus infection when they get the flu."
That's because the flu virus destroys protective cells lining the respiratory tract, making it easier for staph germs to attach themselves. Plus, patients with flu have more difficulty clearing mucus lodged in their lungs, making pneumonia more likely.
MRSA germs "can get a foothold and cause pneumonia that they wouldn't have caused if the influenza virus hadn't been infecting," said Dr. Alfred DeMaria, director of communicable disease control for the Massachusetts Department of Public Health.
"It's a serious problem. Any pediatric complication of influenza is a big concern because, obviously, that's a dangerous situation."
In Massachusetts, two of the four children who succumbed to flu this year also harbored MRSA.
A 15-year-old Newton boy and a 12-year-old Worcester County girl who died of flu had also developed MRSA infections. Health agencies such as DeMaria's are more closely tracking such cases.
In New Hampshire, the state Department of Health & Human Services now reviews death certificates as soon as they're filed, looking for evidence of flu and MRSA, said Dr. Jose Montero, the state's public health director. One New Hampshire child died this winter of the flu, but did not have MRSA.
While MRSA infections can't be treated with the most common antibiotics, they may respond to higher-powered drugs. Also, flu vaccine may help limit the severity of illness, DeMaria said.
At the CDC, investigators decided to review the medical charts of nearly all children admitted to Atlanta-area hospitals with the flu in the winter of 2006-2007. They found that 11 percent of the youngsters also suffered from staph infections, with a little more than half caused by the drug-resistant type.
"There are so many unanswered questions," said Carrie Reed, an epidemiologist in the agency's flu surveillance branch who reported the findings last week at a scientific conference. "It's something we're going to continue looking at and, hopefully, come up with some better conclusions soon."
Stephen Smith can be reached at stsmith@globe.com.
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