Monday, 21 November 2011
Meningococcal disease – the frightening aspect of public health, and a germinating success.
It is not common that I hear fear in people’s voices, but it happened a few times in the past week. That sense of emergency and dread that fear causes. The cause was a couple of unrelated cases of meningococcal disease. Sure, the expected rate is 1 per 100,000 population per year (or roughly 1 in 5 Million in any given week) and we all need to be prepared to respond and manage the situations. Something most public health professionals will be involved with at least some point in their career – and it appropriately is handled as an emergency. Many in Canadian public health will have be engrossed in at least one Meningococcal C outbreak, the most recent that I recall being over the Western provinces in 1999-2001. Fortunately all Canadian jurisdictions now provide childhood meningococcal programs, although variations exist in the primary, catch-up and reinforcement scheduling which confuses the best of professionals. Canada’s lack of a unified immunization approach unmasked once again.
Detailed statistics and vaccine recommendations can be found at NACI meningococcal disease update 2009.
The mainstay for decades for preventing secondary transmission of meningococcal disease has been short term antibiotics. Rates in the immediate period after a case amongst household contacts are nearly 1000 times higher than in the general population – sounds like a huge increase. This converts to less than 1 in 100 household contacts. For those further distant like health care providers involved in care, the rate may be 25 times the general population, or about one in 200,000 workers exposed to a case of disease. Public health should be treating the situation as urgent, but perhaps it is worth remembering what the risks actually are. There are tangible and measurable risks for the antibiotics in use as well.
The flip side of this coin is that up to 10% of invasive meningococcal cases result in a fatality, the highest rate being amongst meningococcal C serotypes which has twice the fatality rate as other serotypes. The dread is often that meningococcal disease strikes healthy adolescents or young adults at the prime of their life. As one person said to me, is this the “really really really bad meningitis”?There is evidence from the UK and Quebec that post vaccination programs result in the reduction in meningococcal illness. The major gap in our defense has been the lack of an effective meningococcal B vaccine, and that may be just around the corner. It is less likely that we will bid farewell to meningococcal illnesses in a similar fashion to Hemophilus influenza, but dramatic reductions could reduce the fear and anxiety that outbreaks and tragic deaths have fueled.