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Changes in Meningococcal Strains in the Era of a Serogroup C Vaccination Campaign: Trends and Evolution in Belgium during the Period 1997-2012.

Mattheus W, Hanquet G, Collard JM, Vanhoof R, Bertrand S - PLoS ONE (2015)

Bottom Line: This study shows the results of the laboratory-based surveillance of IMD in Belgium over the period 1997-2012.In the late nineties, the incidence of serogroup C disease increased considerably and peaked in 2001, mainly associated with phenotypes C:2a:P1.5,2, C:2a:P1.5 and C:2a:P1.2 (ST-11/ET-37 clonal complex).The introduction of the meningococcal C conjugate vaccine has been followed by an 88% significant decrease in serogroup C disease from 2001 to 2004 nationally, yet sharper in Flanders (92%) compared to Wallonia (77%).

View Article: PubMed Central - PubMed

Affiliation: Sections of Bacterial Diseases, Scientific Institute of Public Health, Brussels, Belgium.

ABSTRACT

Background: Invasive meningococcal disease (IMD) is a major cause of bacterial meningitides and septicaemia. This study shows the results of the laboratory-based surveillance of IMD in Belgium over the period 1997-2012.

Methods: The results are based on microbiological and molecular laboratory surveillance of 2997 clinical isolates of N. meningitides received by the Belgian Meningococcal Reference Centre (BMRC) over the period 1997-2012.

Results: Serogroup B has always been a major cause of meningococcal disease in Belgium, with P3.4 as most frequent serotype till 2008, while an increase in non-serotypable strains has been observed in the last few years. Clonal complexes cc-41/44 and cc-269 are most frequently observed in serogroup B strains. In the late nineties, the incidence of serogroup C disease increased considerably and peaked in 2001, mainly associated with phenotypes C:2a:P1.5,2, C:2a:P1.5 and C:2a:P1.2 (ST-11/ET-37 clonal complex). The introduction of the meningococcal C conjugate vaccine has been followed by an 88% significant decrease in serogroup C disease from 2001 to 2004 nationally, yet sharper in Flanders (92%) compared to Wallonia (77%). Since 2008 a difference in incidence of serogroup C was observed in Flanders (0-0.1/100,000) versus Wallonia (0.1-0.3/100,000).

Conclusion: This study showed the change in epidemiology and strain population over a 16 years period spanning an exhaustive vaccination campaign and highlights the influence of regional vaccination policies with different cohorts sizes on short and long-term IMD incidences.

No MeSH data available.


Related in: MedlinePlus

Number of laboratory confirmed invasive meningococcal disease cases per serotype in Belgium, 1997–2012.(A): serogroup B; (B): serogroup C.
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pone.0139615.g002: Number of laboratory confirmed invasive meningococcal disease cases per serotype in Belgium, 1997–2012.(A): serogroup B; (B): serogroup C.

Mentions: The serotype distribution of invasive meningococcal isolates is shown in Table 2. During this period, the serogroup:serotype combinations B:4, C:2a and C:2b together accounted for 57.5% of the serotyped isolates, non-typable (NT) isolates represented 17%. Serotype 2a was the most commonly identified among serogroup C meningococci. However, the increase of serogroup C was first associated with a rise of both serotype 2a and 2b. Serotype 2b was predominant in 1999 and mainly recovered in the province of West-Flanders (especially C:2b:P1.2,5 isolates). But between 2000 and 2001, the number of C:2a isolates tripled (from 40 to 122 strains) and in 2001, serotype 2a was responsible for 68% (122/179) of serogroup C infections. Seventy-three per cent of these infections were detected in Flanders (especially in the province of Antwerp, 30.3%). Serotype 2a remained the major serotype in serogroup C after the vaccination campaign, although at a much lower numbers, while C:2b isolates completely disappeared since 2008 (Fig 2A). Between 2001 and 2004, 14 B:2a:P1.5,2 and 5 B:2a:P1.2 strains were isolated in Flanders (especially in the provinces of East-Flanders and Antwerp), though B:2a meningococci were scarcely detected in the 1990s and hints at a possible capsule switching.


Changes in Meningococcal Strains in the Era of a Serogroup C Vaccination Campaign: Trends and Evolution in Belgium during the Period 1997-2012.

Mattheus W, Hanquet G, Collard JM, Vanhoof R, Bertrand S - PLoS ONE (2015)

Number of laboratory confirmed invasive meningococcal disease cases per serotype in Belgium, 1997–2012.(A): serogroup B; (B): serogroup C.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591272&req=5

pone.0139615.g002: Number of laboratory confirmed invasive meningococcal disease cases per serotype in Belgium, 1997–2012.(A): serogroup B; (B): serogroup C.
Mentions: The serotype distribution of invasive meningococcal isolates is shown in Table 2. During this period, the serogroup:serotype combinations B:4, C:2a and C:2b together accounted for 57.5% of the serotyped isolates, non-typable (NT) isolates represented 17%. Serotype 2a was the most commonly identified among serogroup C meningococci. However, the increase of serogroup C was first associated with a rise of both serotype 2a and 2b. Serotype 2b was predominant in 1999 and mainly recovered in the province of West-Flanders (especially C:2b:P1.2,5 isolates). But between 2000 and 2001, the number of C:2a isolates tripled (from 40 to 122 strains) and in 2001, serotype 2a was responsible for 68% (122/179) of serogroup C infections. Seventy-three per cent of these infections were detected in Flanders (especially in the province of Antwerp, 30.3%). Serotype 2a remained the major serotype in serogroup C after the vaccination campaign, although at a much lower numbers, while C:2b isolates completely disappeared since 2008 (Fig 2A). Between 2001 and 2004, 14 B:2a:P1.5,2 and 5 B:2a:P1.2 strains were isolated in Flanders (especially in the provinces of East-Flanders and Antwerp), though B:2a meningococci were scarcely detected in the 1990s and hints at a possible capsule switching.

Bottom Line: This study shows the results of the laboratory-based surveillance of IMD in Belgium over the period 1997-2012.In the late nineties, the incidence of serogroup C disease increased considerably and peaked in 2001, mainly associated with phenotypes C:2a:P1.5,2, C:2a:P1.5 and C:2a:P1.2 (ST-11/ET-37 clonal complex).The introduction of the meningococcal C conjugate vaccine has been followed by an 88% significant decrease in serogroup C disease from 2001 to 2004 nationally, yet sharper in Flanders (92%) compared to Wallonia (77%).

View Article: PubMed Central - PubMed

Affiliation: Sections of Bacterial Diseases, Scientific Institute of Public Health, Brussels, Belgium.

ABSTRACT

Background: Invasive meningococcal disease (IMD) is a major cause of bacterial meningitides and septicaemia. This study shows the results of the laboratory-based surveillance of IMD in Belgium over the period 1997-2012.

Methods: The results are based on microbiological and molecular laboratory surveillance of 2997 clinical isolates of N. meningitides received by the Belgian Meningococcal Reference Centre (BMRC) over the period 1997-2012.

Results: Serogroup B has always been a major cause of meningococcal disease in Belgium, with P3.4 as most frequent serotype till 2008, while an increase in non-serotypable strains has been observed in the last few years. Clonal complexes cc-41/44 and cc-269 are most frequently observed in serogroup B strains. In the late nineties, the incidence of serogroup C disease increased considerably and peaked in 2001, mainly associated with phenotypes C:2a:P1.5,2, C:2a:P1.5 and C:2a:P1.2 (ST-11/ET-37 clonal complex). The introduction of the meningococcal C conjugate vaccine has been followed by an 88% significant decrease in serogroup C disease from 2001 to 2004 nationally, yet sharper in Flanders (92%) compared to Wallonia (77%). Since 2008 a difference in incidence of serogroup C was observed in Flanders (0-0.1/100,000) versus Wallonia (0.1-0.3/100,000).

Conclusion: This study showed the change in epidemiology and strain population over a 16 years period spanning an exhaustive vaccination campaign and highlights the influence of regional vaccination policies with different cohorts sizes on short and long-term IMD incidences.

No MeSH data available.


Related in: MedlinePlus