A Short Review of Serogroup C Meningococcal Conjugate Vaccines
The schedules used varied and a number of national schedules have been revised as experience with MenC vaccine has been gained (see the section on vaccine effectiveness below) and new vaccines have become available. A combined Hib–MenC vaccine conjugated to tetanus toxoid manufactured by GSK and a conjugate vaccine targeting serogroups A, C, W135 and Y conjugated to CRM197 manufactured by Novartis are now licensed in Europe. Some countries routinely offer a MenC-containing vaccine as a single dose after one year of age, while others schedule a two-dose primary course (a three-dose course in infancy is no longer used). A booster dose may also be routinely offered, usually given shortly after the first birthday or in adolescence.23
Available coverage data within Europe show high acceptance of the MenC vaccine. For example, in England, school children targeted by the catch-up campaign achieved 85 % coverage overall2
and the
national catch-up campaign in The Netherlands between June and November 2002 achieved 94 % coverage in children one to 18 years of age.24
Routine infant immunisation coverage in England rapidly reached the levels attained for other vaccines and was 94 % by second birthday from October to December 2009.25
Coverage for the
Hib–MenC booster introduced in 2006 and offered at 12 months of age was 90 % for the same period.
Immunisation against serogroup C meningococcal disease has also been recommended in Canada from 200126,27 2003.28
and in Australia from in 1989–1991 to 32.6 % in 199629
In the US, cases of serogroup Y disease rose from 2 % of disease and a quadrivalent meningococcal
conjugate vaccine, including capsular groups A, C, W135 and Y, has been recommended for routine vaccination of young adolescents (11–12 years of age) since 2005.30
Vaccination before high-school entry
(at approximately 15 years of age) was also recommended for those who had not previously received the quadrivalent vaccine. A serogroup A conjugate vaccine, MenAfriVac™, has been developed and received pre-qualification from the World Health Organization (WHO) in June 2010. This cleared the way for the introduction of the vaccine in Burkina Faso, Mali and Niger late in 2010. WHO compiled data showed a marked impact with these countries recording their lowest number of serogroup A cases ever in the 2010/2011 epidemic season.31
The Impact of Serogroup C Meningococcal Conjugate Vaccines
Meningococcal Disease Epidemiology
The early impact in European countries using MenC vaccines is summarised in Figure 2, which illustrates a marked reduction in serogroup C disease in European countries using a MenC vaccine, with a consistent pattern of disease in countries not using the vaccine. There was also a decrease in the number of cases of serogroup B between 1999 and 2006 in European countries using a MenC vaccine; however, group C disease decreased by 90 % and serogroup B fell by around 40 % over this period.32
This suggests that
the change in serogroup B incidence was more likely to be due to secular fluctuations whereas the serogroup C impact was largely attributable to vaccination.
Reports of the marked and specific impact of the introduction of a MenC vaccine on serogroup C disease have now been published from different individual countries. Cases in the targeted age groups fell rapidly after the introduction of MenC in England and Wales (see Figure 3). The incidence of serogroup C disease in the under 20-year-old age group in England and Wales fell from 5.34
EUROPEAN INFECTIOUS DISEASE <20 years 20+ years
per 100,000 population in 1998–1999 to 0.03 per 100,000 population in 2008–2009:33
Figure 2: Incidence of Serogroup C Invasive Meningococcal Disease by Routine Meningococcal C Conjugate Vaccine Use and Epidemiological Year in Reporting European Countries
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
0
Epidemiological year Routine MCC vaccination No routine MCC vaccination Countries with consistent data only Derived from EU-IBIS data. MCC = meningococcal C conjugate.
Figure 3: Cases of Serogroup C Disease in Those Under 20 Years of Age and Those 20 Years and Older in England and Wales
100 200 300 400 500 600 700 800
0
a reduction of 99.1 %. There was a concurrent fall in the number of deaths from serogroup C disease in those under 20 years of age, from 78 in 1998–1999 to only one in the three years between 2006–2007 and 2008–2009 (provisional data from the Health Protection Agency.33
Reductions in disease were also seen in age groups that were not targeted for immunisation (see Figure 3). In those 25 years of age and over, the vast majority of whom would not have been offered the MenC vaccine, the incidence of serogroup C disease fell from 0.55 per 100,000 population to 0.02 per 100,000 population between 1998–1999 and 2008–2009: a reduction of 95.6 % and strong evidence of a herd immunity effect.33
The number of deaths also fell in those 20 years of age and older, from 40 in 1998–1999 131
Percentage
Incidence (per 100,000 population)
1999/2000 2000/2001 2001/2002 2002/2003 2003/2004 2004/2005 2005/2006
1998/1999 1999/2000 2000/2001 2001/2002 2002/2003 2003/2004 2004/2005 2005/2006 2006/2007 2007/2008 2008/2009 2009/2010
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