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Seasonal variation in meningococcal disease in Denmark: relation to age and meningococcal phenotype

Elise S Jensen1, Søren Lundbye-Christensen, Lars Pedersen

  • 1Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. esjensen@dadlnet.dk

Scandinavian Journal of Infectious Diseases
|July 4, 2003
PubMed

Insights

Meningococcal disease (MD) shows seasonal variation, particularly in children aged 5-14 years and specific bacterial strains. This pattern is influenced by age and meningococcal phenotype, but not gender.

Area of Science:

  • Epidemiology
  • Infectious Disease Dynamics
  • Public Health

Background:

  • Meningococcal disease (MD) exhibits known seasonal patterns.
  • However, the influence of age, gender, and specific meningococcal phenotypes on this seasonality remains unclear.

Purpose of the Study:

  • To investigate the seasonal variation in meningococcal disease.
  • To determine if this variation is associated with age, gender, or meningococcal phenotype.
  • To quantify the magnitude of seasonal variation using the peak-to-trough ratio (PTR).

Main Methods:

  • Analysis of 413 confirmed cases of MD in North Jutland County, Denmark (1980-1999).
  • Application of a sinusoidal Poisson regression model to assess seasonal patterns.
  • Calculation of peak-to-trough ratios (PTR) to measure the amplitude of seasonal variation.

Main Results:

  • An overall seasonal variation in MD was observed (PTR 2.0).
  • Significant differences in seasonal variation were found across age groups and meningococcal phenotypes, but not genders.
  • The highest seasonal variation was noted in children aged 5-14 years (PTRs 4.9 and 3.7, respectively) and for phenotype C:2a:P1.2,5 (PTR 3.8).
  • Minimal seasonal variation was observed in infants (<1 year) and teenagers (15-19 years).

Conclusions:

  • Seasonal variation in meningococcal disease is dependent on patient age and the specific meningococcal phenotype.
  • The most pronounced seasonality occurs in children aged 5-14 years and with phenotype C:2a:P1.2,5.
  • These findings highlight specific demographic and microbiological factors influencing MD seasonality.

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