Due to the recent outbreaks of meningococcal disease in various regions of Canada, we have been flooded with requests for information about the disease, the vaccines currently used in Canada and concerns about adverse reactions. The following compilation of articles, web sites and news reports is intended to present an overview of some relevant perspectives currently under discussion.
According to The National Advisory Committee on Immunization's statement on recommended use of meningococcal vaccines, "Meningococcal disease is endemic in Canada with periods of increased activity occurring roughly every 10 to 15 years, but with no consistent pattern. The incidence of meningococcal disease has varied considerably with different serogroups, age groups, geographic location and time. The last major epidemic of meningococcal disease occurred in 1940-1943 (serogroup A), when the peak incidence was close to 13 per 100,000 population per year. Since then, the overall incidence of disease has remained <= 2 per 100,000 per year (range 0.5 to 2.1). There have been sporadic localized outbreaks and periods of elevated activity (serogroup C) during 1989-1993 and 2000-present. Case by case data for meningococcal disease is available from 1985 to 2000. During this period, there were an average of 303 cases of the disease reported per year in Canada. Cases of meningococcal disease occur year round, but the majority present in the winter months."
The NACI statement can be viewed at:
http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/01vol27/27sup/acs6.html English
http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/01vol27/27sup/dcc6.html French
In the first few months of the year, 129 cases of invasive meningococcal disease were reported in Canada up to April 20, 2001, of which 57% were confirmed to be caused by group C. Of the 13 deaths in those four months, seven were group C’s.
http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/04vol30/dr3003ea.html English
PDF Version English
http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/04vol30/rm3003fa.html French
PDF Version French
Prior to the recent licensing of a new, genetically engineered “Group C Conjugate” vaccine, an older vaccine comprised of “a freeze-dried preparation of the group-specific polysaccharide antigens from Neisseria meningitidis, Group A, C, Y and W-135” was employed in areas reporting outbreaks of the disease. The new, “Group C Conjugate” vaccine is being injected into hundreds of thousands of people in Canada. In the fall of 2001, the province of Quebec committed $100 million to vaccinate everyone from the age of 2 months to 20 years with the new vaccine. The Group C Conjugate vaccine was test marketed on millions of British children, where extensive adverse reactions were reported. Read articles on the British experience in the list of links provided below.
Chiron Corporation of Emeryville, California developed and manufactures Menjugate and has contracted Merck Frosst Canada as the Canadian distributor of its product. It retails for $89 a dose. It's not known exactly how long the drug's immunizing effects last, but Dr. Mitchell Shulman, Merck Frosst Canada's assistant director of medical services said they persist for at least three years.
Unlike the U.S., in Canada access to specific information about vaccine adverse reactions is not readily available. To get an idea of the kinds of adverse events following the quadrivalent polysaccharide meningococcal vaccine and reported to VAERS - the U.S. Vaccine Adverse Events Reporting System’s data base, PROVE’s web page provides a random sample of these reactions. With appreciation to Dawn Richardson of PROVE (Parents Requesting Open Vaccine Education) for making this information available on their website:
Vaccine Info - Reported Meningococal Reactions
The meningococcal organism is known for its ability to rapidly switch serogroups when put under pressure such as exerted by mass vaccination programs. In a letter to the New England Journal of Medicine, German researchers expressed the following concern -
“The rapidity of the serogroup switching arouses concern about the induction of herd immunity against single serogroups by vaccination programs in which capsular antigens (e.g., serogroup C polysaccharides) are used. Without lowering the incidence of meningococcal disease in the long run, such programs may rapidly increase the incidence of serogroup B meningococcal disease, for which no vaccine is available.” (The New England Journal of Medicine, January 20, 2000 - Vol. 342, No. 3).
During the recent and continuing meningococcal outbreaks in the Edmonton, Alberta area, a new “clone” of the type C organism was identified, as the infecting organism in the majority of cases of invasive meningococcal disease in that area, and may very well be a result of the “switching” or mutation this bacteria undertakes so readily.
Parents want to protect their children from serious diseases like meningitis and deserve honest answers for the pressing questions that arise when outbreaks occur. Some questions are:
- -Why are these outbreaks of serious cases of the disease clustering and becoming more common?
- -If most people develop natural immunity to the bacteria with no consequences and some even carry it, what do the people who have died or become very sick from it have in common?
- -Could the bacteria have mutated into a more aggressive organism? And if so, why?
- -Can the vaccine weaken the immune system making a vaccinated person more vulnerable to contracting the disease?
- -Do recently vaccinated children pose a risk to unvaccinated children?
- -Have the children and adults who have had a serious outcome from the disease recently been on any medications, had any environmental exposures, or have they recently been vaccinated for anything else that could have depressed their immune systems?
Neither the older, quadrivalent meningococcal vaccine, nor the new Group C Conjugate vaccine protect from serogroup B meningococcal disease, which comprises a large percentage of cases occurring in Canada. In 1997 & 1998 type B meningococcal disease accounted for 47.9% and 50% cases respectively. To view the distribution of serotypes of meningococcal disease in Canada:
http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/00vol26/dr2621e.html English
http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/00vol26/rm2621f.html French |
