There are several strains of meningococcus. The most common are called Groups A, B, C, Y and W. Vaccines are used routinely to protect against groups ACYW. Two new vaccines against group B have been approved for use in Canada in 2013.
In Canada since 2007, Group B strains have caused almost 60% of cases or an average of 111 cases per year. The frequency of group B cases does not vary very much from year to year. However, the number of cases caused by group C, Y and W do vary from year to year. The frequency of Group C disease has decreased significantly since the introduction of routine immunization with Group C conjugate vaccine in 2005-6 in infants and older children. From a peak of 202 cases in 2001, the number of group C cases decreased by 90%, to an average of 19 cases per year between 2007-2011.. The average annual number of cases caused by serogroup W and Y since 2007 were 11 and 34 respectively.
Children across Canada are routinely vaccinated with one of the conjugated group C vaccines (Menjugate C® or NeissVac C®) that protect only against disease caused by group C at 1 year of age or earlier. In addition, many provinces also use these vaccines in children in school-based programs between 10-13 years of age.
Conjugated ACYW vaccine protects against meningococcal disease caused by groups A,C,Y and W-135. It can be used in children 2 years of age and older previously vaccinated against Group C, thereby serving as a booster of immunity to group C while also providing protection against groups A, Y, and W. It can also be used in children 2 years of age and older who have not previously been vaccinated with any meningococcal vaccine.
In Alberta, New Brunswick, Newfoundland and Labrador, Ontario, Prince Edward Island, and Saskatchewan and in new recruits in the Canadian Forces, Conjugated ACYW vaccine has replaced the group C conjugate vaccine for routine use in adolescents in the provincial immunization program. It is hoped that other provinces will do the same to maximize protection against meningococcal disease.
Studies have shown that the conjugated ACYW vaccine is also effective in infants, but a series of injections is required to induce immunity, as with other infant vaccines. It is likely that the 4-in-1 will replace the group C conjugated vaccine currently used in infants.
There are over 80 types of this bacterium. They are primary causes of pneumonia, bronchitis, ear and sinus infections. Less frequently they cause meningitis.
Hib was the most common cause of bacterial meningitis until 1992. It also caused other serious infections including pneumonia, severe throat infections, skin and joint infections. Infants from 6 to 18 months and children under the age of 5 were most commonly infected. Hib infections are rare in Canada because since 1992 infants have been routinely immunized with Hib vaccine. In Canada, the conjugated Hib vaccine is given to infants at 2, 4, 6, and 18 months of age as part of a combined 5-in-1 vaccine containing diphtheria toxoid, tetanus toxoid, acellular pertussis vaccine, and inactivated polio vaccine.