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Transmissibility and pathogenicity of the emerging meningococcal serogroup W sequence type-11 complex South American
Matthieu Domenech de Cellès1,2,3, Helen Campbell4, Ray Borrow5
1Université Paris-Saclay, UVSQ, Univ. Paris-Sud, Inserm, CESP, Anti-infective evasion and pharmacoepidemiology team, F-78180, Montigny-Le-Bretonneux, France. domenech@mpiib-berlin.mpg.de.
Background:
The recent emergence of strains belonging to the meningococcal serogroup W (MenW) sequence type-11 clonal complex and descending from the South American sub-lineage (MenW:cc11/SA) has caused significant shifts in the epidemiology of meningococcal disease worldwide. Although MenW:cc11/SA is deemed highly transmissible and invasive, its epidemiological characteristics have not yet been quantified.
Methods:
We designed a mathematical model of MenW transmission, carriage, and infection to analyze the recent epidemiology of invasive disease caused by MenW:cc11/SA strains and by other MenW strains in England and in France. We confronted that model with age-stratified incidence data to estimate the transmissibility and the invasiveness of MenW:cc11/SA in England, using the data in France as a validation cohort.
Results:
During the epidemiological years 2010/2011-2014/2015 in England, the transmissibility of MenW:cc11/SA relative to that of other MenW strains was estimated at 1.20 (95% confidence interval, 1.15 to 1.26). The relative invasiveness of MenW:cc11/SA was also found to exceed unity and to increase with age, with estimates ranging from 4.0 (1.6 to 9.7) in children aged 0-4 years to 20 (6 to 34) in adults aged ≥ 25 years. In France, the model calibrated in England correctly reproduced the early increase of MenW:cc11/SA disease during 2012/2013-2016/2017. Most recent surveillance data, however, indicated a decline in MenW:cc11/SA disease. In both countries, our results suggested that the transmission of MenW:cc11/SA carriage possibly started several months before the first reported case of MenW:cc11/SA disease.
Discussion:
Our results confirm earlier suggestions about the transmission and the pathogenic potential of MenW:cc11/SA. The main limitation of our study was the lack of age-specific MenW carriage data to confront our model predictions with. Furthermore, the lesser model fit to the most recent data in France suggests that the predictive accuracy of our model might be limited to 5-6 years.
Conclusions:
Our study provides the first estimates of the transmissibility and of the invasiveness of MenW:cc11/SA. Such estimates may be useful to anticipate changes in the epidemiology of MenW and to adapt vaccination strategies. Our results also point to silent, prolonged transmission of MenW:cc11/SA carriage, with potentially important implications for epidemic preparedness.
Insights
The study quantifies the transmissibility and invasiveness of meningococcal serogroup W (MenW) sequence type-11 clonal complex (MenW:cc11/SA) strains. These findings aid in anticipating MenW epidemiology shifts and adapting vaccination strategies for better epidemic preparedness.
Area of Science:
- Epidemiology
- Mathematical Modeling
- Public Health
Background:
- Emergence of meningococcal serogroup W (MenW) sequence type-11 clonal complex, South American sub-lineage (MenW:cc11/SA) strains, has altered global meningococcal disease epidemiology.
- MenW:cc11/SA strains are recognized as highly transmissible and invasive, yet their specific epidemiological characteristics remain unquantified.
Purpose of the Study:
- To quantify the transmissibility and invasiveness of MenW:cc11/SA strains.
- To analyze the epidemiology of invasive meningococcal disease caused by MenW:cc11/SA and other MenW strains in England and France.
Main Methods:
- Development of a mathematical model for MenW transmission, carriage, and infection.
- Confronting the model with age-stratified incidence data from England and France.
- Estimation of relative transmissibility and age-dependent invasiveness of MenW:cc11/SA.
Main Results:
- MenW:cc11/SA demonstrated a relative transmissibility of 1.20 in England (2010/2011-2014/2015).
- Relative invasiveness increased with age, from 4.0 in children (0-4 years) to 20 in adults (≥25 years).
- Model validation in France showed early MenW:cc11/SA increase, though recent data indicated a decline; prolonged silent carriage transmission was suggested.
Conclusions:
- The study provides the first quantitative estimates of MenW:cc11/SA transmissibility and invasiveness.
- Findings support adapting MenW vaccination strategies and improving epidemic preparedness.
- Lack of age-specific carriage data was a limitation; model predictive accuracy may be limited to 5-6 years.
