How to Calculate HIB

Hib is an acronym for Haemophilus influenzae type b. Hib continues to take lives among children in developing countries and worldwide; 400,000 children annually die as a direct result. Hib is the leading cause of bacterial meningitis deaths and the second-leading cause of bacterial pneumonia deaths worldwide. Lifesaving vaccines are available for this disease; however, limited awareness of the impact of Hib has stands in the way of progress with the goal of reducing Hib death rates. It is possible to calculate Hib rates in a timely fashion, which can help affected countries to take steps in combating Hib.

Instructions

Meningitis Incidence Rate Method

• 1

  Select an appropriate location where the Hib meningitis rate can be calculated. An appropriate site would be one where there are one or more hospitals that have well-defined service boundaries, where most children go if they have contracted meningitis and where the Hib vaccine is not often used. Other requirements for the hospitals chosen for study are those where physicians perform lumbar punctures (spinal tap) on children suspected of having meningitis.

• 2

  Count the number of cases of meningitis cause by Hib, as confirmed by culture tests at the hospital. Not all hospitals may have the facilities needed to perform culture tests, but surveying hospitals that perform culture tests is a necessary part of this method. Then, calculate the percentage of cases caused by Hib.

• 3

  Count the total number of purulent cerebrospinal fluid samples (spinal taps) for the time period being considered.

• 4

  Add the number of culture-confirmed Hib cases and estimated culture-negative Hib cases.

• 5

  Estimate the number of children with suspected meningitis who did not get a lumber puncture, according to information provided by local pediatricians. Add this number to the total figure.

• 6

  Multiply the total number of Hib meningitis cases calculated by a factor of five, which two studies have determined to be the ratio between Hib meningitis cases and the total number of Hib pneumonia cases. Adding the two numbers provides an approximate figure which you can then extrapolate using the ratio of the population of children in the study area to the population of children in the entire country. This provides a good estimate for calculating the impact of Hib in specific countries which can, in turn, lead to incentive for a more concentrated effort for vaccinating children.