Haemophilus influenzae Invasive Disease, 2012

Eighty-six cases of invasive Haemophilus influenzae disease (1.61 per 100,000 population) were reported in 2012. Cases ranged in age from newborn to 100 years (median, 67.5 years). Allowing for more than one syndrome per case, 44 (51%) cases had pneumonia, 21 (24%) had bacteremia without another focus of infection, 10 (12%) had meningitis, 3 (3%) each had epiglottitis and septic arthritis, 2 (2%) each had abscess, cellulitis, septic shock, and otitis media, and 1 (1%) had endometritis. Eleven (13%) cases died.

Of 83 H. influenzae isolates for which typing was performed at PHL, 18 (22%) were type f, 3 (4%) type b, 2 (2%) type e, 6 (7%) type a, and 54 (65%) were untypeable. Serotype f represented on average 14% of case-isolates from 2006-2011. The increase in 2012 serotype f cases was associated with increased risk of meningitis and fatal outcome.

Three cases of type b (Hib) disease occurred in 2012, compared to 3 cases in 2011, 1 case in 2010, and 2 cases in 2009. One Hib case occurred in a 4 month-old child with meningitis who had received 1 dose of vaccine at 2 months of age and was exposed to unvaccinated children. A second 4 month-old child who was not vaccinated had otitis media and pneumonia. The third case of Hib was in an unvaccinated 4 year-old who had pneumonia and epiglottitis. No Hib cases were found in adults. All 3 cases survived.

The 11 deaths occurred in patients ranging in age from 50 to 96 years. Five cases had pneumonia (of these, 1 also had cellulitis), 2 had epiglottitis and 4 cases had bacteremia without another focus of infection. All 11 cases had H. influenzae isolated from blood and all had underlying medical conditions. Of the 11 cases who died, 7 case-isolates were untypeable, 2 were serotype f, and 1 was serotype e, and 1 isolate was not available for typing.

• For up to date information see>> Haemophilus influenzae (invasive disease)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2012