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CDC sees 'worrisome' spike in swine flu-linked bacterial pneumonia

November 25, 2009 | 11:56 am

PigFederal officials said today they have noticed "a worrisome spike in serious pneumococcal disease" linked to infections with pandemic H1N1 influenza. Health authorities normally see an increase in such infections associated with seasonal flu, but this year the rate is substantially higher than normal and the disease is striking younger people than normal, according to Dr. Anne Schuchat, director of the Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases.

The pneumococcal infections typically occur when an influenza infection weakens the lining of the lungs, allowing bacteria that normally reside in the nose and throat to make their way down to the lungs, where they cause severe disease, inflaming the lungs and often spreading through the blood to other organs. The infections can be fatal and autopsies of deaths associated with swine flu typically show that about 30% of the patients had such an infection. Most of the pneumococcal infections can be prevented with a vaccine called Pneumovax that is recommended for people with medical conditions that leave them at high risk, but only about a quarter of people at risk have received an immunization.

The problem with pneumococcal infections is showing up in the CDC's Active Bacterial Core surveillance program, which monitors infections at 10 sites across the country. In the Denver metropolitan area, one of the sites, there are typically about 20 such infections in October. This year, there were 58, according to the ABC surveillance. "We don't think this is the only area of the country where this is going on," Schuchat said at a morning news conference. "There is some evidence of an increase at multiple sites, but there is probably more timely reporting in Denver." And while pneumococcal pneumonia most commonly strikes the elderly, most of the increase in infections in Denver occurred among people under age 60. A CDC team is going to that city to investigate.

The CDC will not publish new flu activity data until next week because of the Thanksgiving holiday. Schuchat said 61.2 million doses of swine flu vaccine are available for ordering by the states as of today, an increase of more than 7 million doses since last week. "We're expecting to see vaccination efforts really step up as we head into December," she said.

The agency posted its first assessment of potential side effects from vaccinations today. "A lot of people have been waiting for this report, and we think it is good news," Schuchat said. "So far, everything that we have reviewed is extremely reassuring. The patterns we are seeing are pretty much exactly what we see with seasonal flu," which is not surprising because the two vaccines are manufactured the same way. More than 94% of reports to the Vaccine Adverse Events Reporting System, or VAERS, are classified as not serious, she said, and range from a sore arm to redness and tenderness at the injection site.

There are 10 reports of Guillain-Barre Syndrome, which are still being investigated. That syndrome is a particular concern because there were reports of an increase in incidence following a 1957 swine flu vaccination program. "The number of reports, given the number of doses [of swine flu vaccine given], is not at all notable," she said. "It's important to remember that Guillain-Barre Syndrome happens, with or without the vaccine. Every week, 80 to 160 people come down with it." Just because an event was reported to VAERS does not mean that it was caused by the vaccine. For example, one severe adverse event reported to VAERS was a fatality in a car crash. Schuchat also noted that the CDC has organized an external group of experts to monitor the adverse event reporting to look for red flags, and so far "they haven't found any."

-- Thomas H. Maugh II

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