Poster Presentation Lancefield International Symposium for Streptococci and Streptococcal Diseases 2025

A streptococcal vaccine to prevent cellulitis in older adults (#311)

Laurens Manning 1 2 3 , Jeffrey Cannon 2 , Alma Fulurija 2 , Michael Morici 2 , Jonathan Carapetis 2
  1. University of Western Australia, Shenton Park, WA, Australia
  2. END RHD, The Kids Institute, Perth, WA, Australia
  3. Department of Infectious Diseases, Fiona Stanley Hospital, Perth, WA, Australia

Strep A vaccine development pathways have focused on opportunities to prevent Strep A pharyngitis, with the ultimate goal of reducing the global burden of RHD, particularly for children and young people in low- and middle-income countries and in First Nations peoples in some high-income countries.

The large burden of cellulitis in older adults from high income settings could warrant a reappraisal of Strep A vaccine development pathways by providing an additional indication and strengthening the economic rationale. This would have additional value if there was cross protection between S. pyogenes and S. dysgalactiae subspecies equisimilis (SDSE). Preventing recurrent infections is a key patient-centred outcome.

In this presentation, epidemiological data from data linkage studies of cellulitis and invasive disease caused by S. pyogenes and SDSE shows a striking increase in age-adjusted incidence, with the highest rates amongst older adults. Additionally, recent prospective studies of cellulitis exploring serological responses to S. pyogenes vaccine candidate antigens which suggest that:

  1. Beta-haemolytic streptococci account for >40% of cellulitis episodes
  2. SDSE appears to be the predominant cause of lower limb cellulitis (rather than pyogenes)
  • Some level of cross-protection between pyogenes, SDSE and possibly Group B streptococcus is plausible

Supporting economic analyses indicate that in high income settings cellulitis in older adults may be the highest value indication for a Strep A vaccine.

Further work to explore the role of a vaccine to prevent cellulitis in older adults should be integrated into the current Strep A vaccine development pipeline.