The case count continues to climb as people contract a rare form of meningitis that produces strokelike symptoms. As of this posting, 14 patients have died and 156 others have fallen ill across 11 states. The U.S. Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) have traced the unusual outbreak to three lots of steroid medication injected into the spine to treat pain.
Meningitis is an infection of the membranes surrounding the spinal cord and brain. It can be caused by a number of infectious agents. Viral meningitis is relatively benign, and those infected may recover without specific therapy. Bacterial meningitis—particularly meningococcal meningitis—can be acute and severe but is treatable if diagnosed early. The current outbreak is fungal meningitis, a rare form because fungi do not usually infect individuals with a healthy immune system. Unlike viral and bacterial meningitis, fungal meningitis is not contagious—and it is treatable if detected early.
The tainted drug is preservative-free methylprednisolone acetate contaminated with different fungus species. The CDC has identified two kinds of fungi in the meningitis patients: Aspergillus, commonly found in moldy leaves, and Exserohilum, which is involved in wood rot. Epidural steroid injections—a procedure to relieve back pain—likely delivered the fungus adjacent to membranes surrounding the spinal cord, according to the ongoing investigation. The meningitis symptoms can take weeks or even months to develop.
The contaminated lots came from the New England Compounding Center beginning May 21. The center, which voluntarily recalled all its products last week, is a so-called compounding pharmacy: it creates tailored formulations of medications by packaging different doses or changing a medicine from solid to liquid, for example. Compounding facilities do not fall under the same regulatory categories as larger pharmaceutical companies.
To learn more about the outbreak, Scientific American spoke with William Schaffner, an infectious diseases specialist and chair of the Department of Preventive Medicine at Vanderbilt University School of Medicine. He describes what we know about fungal meningitis, how it is being treated and how the unfolding investigation may subject compounding facilities to closer scrutiny.
[An edited transcript of the interview follows.]
How many people are at risk in this outbreak?
The investigation indicates that there were over 17,000 vials of this potentially contaminated medication produced. There may be some variability from vial to vial within each batch. It has been estimated that something like 13,000 people were exposed to this medication; some of it hadn't been used yet by the time the alert went out, and some people received more than one dose. That's very large. If there is a silver lining in this dark cloud, it's that the proportion of people who received this medication who are actually getting sick is rather low. It looks to be less than 5 percent.
What are the symptoms?
The symptoms are insidious. They begin slowly and not very dramatically: fever and chills, headache and a stiff neck from the inflammation. People lose their appetite, feel ill, can be nauseated and can vomit. But there's something else that's subtle: It seems these fungi have the capacity to invade little blood vessels in and around the brain, cause bleeding and produce symptoms that mimic a stroke—difficulty speaking, loss of balance and trouble walking. Those symptoms can occur even without fever, so physicians have to learn that patients who present with stroke symptoms may actually be part of this.