Article Text

Original article
Summer heat: a cross-sectional analysis of seasonal differences in sexual behaviour and sexually transmissible diseases in Melbourne, Australia
  1. Vincent J Cornelisse1,2,
  2. Eric P F Chow1,2,
  3. Marcus Y Chen1,2,
  4. Catriona S Bradshaw1,2,
  5. Christopher K Fairley1,2
  1. 1Central Clinical School, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
  2. 2Melbourne Sexual Health Centre, Alfred Health, Carlton, Victoria, Australia
  1. Correspondence to Dr Vincent J Cornelisse, Melbourne Sexual Health Centre, Alfred Health, 580 Swanston St, Carlton, VIC 3052, Australia; vcornelisse{at}; echow{at}


Objectives To date, no study has correlated seasonal differences in sexual behaviour with the seasonal differences in sexually transmitted infections (STIs); and no seasonal study of STIs has been conducted in the southern hemisphere. Our study aimed to describe seasonal differences in sexual behaviour and correlate this with seasonal differences in STI diagnoses in Melbourne, Australia.

Method This was a cross-sectional study of individuals attending the Melbourne Sexual Health Centre over a 9-year period from 2006 to 2014. We conducted separate analyses for men who have sex with men (MSM) and men who have sex with women (MSW), and women. Seasonal patterns of sexual behaviour and STI positivity were examined within each group.

Results All groups reported a higher number of partners over the preceding three months for consultations in summer compared with winter (MSM mean 5.48 vs 5.03; MSW mean 2.46 vs 2.31; women mean 1.83 vs 1.72). Urethral gonorrhoea diagnoses among MSM were higher in summer compared with winter (OR 1.23, 95% CI 1.04 to 1.46). Similarly, non-gonococcal urethritis (NGU) diagnoses among MSW were the highest in summer (OR 1.11, 95% CI 1.03 to 1.20), but there was no seasonal difference in NGU diagnoses when we adjusted for partner numbers. In women, pelvic inflammatory disease (PID) diagnoses peaked in autumn, when rates were higher than in winter (OR 1.30, 95% CI 1.09 to 1.55).

Conclusions Our results describe a peak in sexual partner number and STI diagnoses during consultations in summer in men and a rise in PID in autumn in women.


Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Supplementary materials

  • Supplementary Data

    This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.