The 20 state outbreak of fungal meningitis which erupted last September has become the largest outbreak of health care associated infections in the US. More than 300 professionals from CDC and thousands of public health professionals nationally were involved, according to CDC epidemiologist Benjamin Park, speaking at the annual Epidemic Intelligence Service (EIS) April conference in Atlanta.

As of late April 2013, 733 cases and 53 deaths have been reported with the largest number reported from Michigan, Tennessee, and Indiana. Caused by the rare mold exserohilum rostratum, the clinical disease was completely new and there was zero clinical experience in dealing with it, according to CDC’s Tom Chiller who helped coordinate the guidance given to clinicians.

It has been called a “catastrophic event” and “disturbing tragedy” by CDC epidemiologists Beth Bell and Rima Khabbaz writing in a recent issue of JAMA.

Early Worries

State and federal agency speakers at a special lunchtime session of the EIS conference noted that the data on the first few cases suggested a high case fatality rate. Also, previous outbreaks linked to spinal injection with contaminated products had found case fatality rates in excess of 40%.

After rapid identification of the source of the outbreak as contaminated methylprednisolone acetate prepared by the New England Compounding Center in Framingham Massachusetts, investigators discovered that almost 14,000 persons had been exposed and were at risk of invasive fungal infection. Doing preliminary math with these figures was very worrisome as it appeared the US was facing a potential for hundreds of cases and deaths from the outbreak.

The Good News

The good news according to Bell and Khabbaz is that scores of cases and deaths appear to have been averted by interventions such as discontinued use of the suspect medication, notification of at-risk patients, communicating with the public, and developing and disseminating treatment guidance as the outbreak continued to unfold. According to CDC, 99% of patients were warned in less than one month of the immediate need to seek medical care. Also, CDC’s meningitis outbreak pages were accessed more than a million times during the outbreak.

Case Fatality Rates

The most compelling evidence for the effectiveness of public health interventions comes from the “dramatic decrease in the 30 day case fatality rate among patients diagnosed with meningitis after the outbreaks was recognized and public health action initiated,” according to Bell and Khabbaz.  That case fatality rate fell from approximately 40% before outbreak detection to below 7% after the outbreak response. The overall CFR with both groups of cases before and after outbreak detection included is 7% as of late April 2013.

Lives Saved

Also speaking at the conference, Tennessee’s health care epidemiologist Marion Kainer stated that she had reliable data on which estimate the value of rapid public health actions and was able to document very convincingly that at least 99 cases were prevented and 69 deaths averted in that state alone.

According to CDC’s Park, over 100 lives were saved nationally as a result of the efforts to achieve early diagnosis and treatment. He added it is rare that public health professionals can point with such certainty to a concrete number of lives saved as a result of prevention efforts. Given the Tennessee data, the CDC estimate may be low since a total of 20 states were involved.

Simply Said

A simpler way of stating the impact of public health actions was presented in a CDC infographic on the outbreak which stated “despite the number of cases increasing, the death rate dramatically decreased thanks to swift public health action.”

Earlier Article

An article appeared in this newsletter last year describing how right thinking and right action by clinicians, epidemiologists, and public health officials helped to save lives. Now we have a fuller picture as evidenced by the case fatality rates of just how effective the public health response has been.

Use this link to read the original article entitled“Clinician and Epidemiologist Are Praised For Alertness and Shoe-Leather Detective Work In Finding Cause Of Fungal Meningitis Outbreak.” http://tinyurl.com/czoutew   ■

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