2009 H1N1 and Pneumococcal Disease in the News

Questions and Answers: 2009 H1N1 and Pneumococcal Disease in the News
November 17, 2009, 12:00 PM ET
November 19, 2009.

2009 H1N1 and Seasonal Influenza Infections and Invasive Pneumococcal Disease
What is invasive pneumococcal disease?
Invasive pneumococcal disease is an infection caused by a type of bacteria called Streptococcus pneumoniae (pneumococcus). Invasive disease means that germs invade parts of the body that are normally free from germs, like blood or spinal fluid. When this happens, disease is usually very severe, causing hospitalization or even death. When pneumococcal bacteria invade the lungs, they can cause pneumonia. They can also invade the bloodstream, causing bacteremia, and/or the tissues and fluids surrounding the brain and spinal cord, causing meningitis.

What does CDC know about invasive pneumococcal disease among people who get 2009 H1N1 or seasonal influenza?
Influenza (flu) infections can make people more likely to develop pneumococcal infections. Pneumococcal infections are a complication of 2009 H1N1 and seasonal flu infections and can cause serious complications, including death. CDC tracks pneumococcal disease through Active Bacterial Core surveillance (ABCs), part of the Emerging Infections Program Network (EIP).

What is Active Bacterial Core surveillance (ABCs)?
ABCs is an active laboratory- and population-based system for tracking important invasive bacterial pathogens (germs). For each case of invasive disease in the surveillance population, a case report with basic demographic information (age, sex, ethnicity, etc.) is completed and bacterial isolates are sent to CDC and other reference laboratories for additional laboratory testing. ABCs currently operates in 10 areas across the United States, representing a population of over 38 million persons.

What percentage of people hospitalized with 2009 H1N1 flu have developed invasive pneumococcal disease?
We do not know the exact percentage. Some people who have 2009 H1N1 flu will develop invasive pneumococcal disease; those who do may not develop symptoms of invasive pneumococcal disease until several days or even a week after they experience flu symptoms. Because of this timing and because not everyone is tested for both infections, we don’t know what percentage of people hospitalized with 2009 H1N1 flu go on to develop invasive pneumococcal disease.

Is 2009 H1N1 flu associated with an increase in invasive pneumococcal disease?
Possibly. Some ABCs sites have seen greater than expected numbers of cases of invasive pneumococcal disease coincident with increases in flu-associated hospitalizations. We don't know whether 2009 H1N1 flu actually caused this increase but CDC is pursuing that question with state and local public health officials. For a graphical representation of this data, please see the chart below, which represents one ABCs site.



abrir aquí para acceder al documento CDC completo:
http://www.cdc.gov/h1n1flu/vaccination/qa_pneumococcal_disease.htm