Dr Sachira Chandrasekara1, Dr Dorothy Ling1
1The Northern Hospital, Epping, Australia
Biography:
Sachira Chandrasekara is a general medicine advanced trainee at Northern Health with an interest in preventative healthcare and perioperative medicine.
Dorothy Ling is an infectious diseases physician with a special interest in infection prevention.
Abstract:
Introduction
Vaccination is highly effective in preventing infection with vaccine-preventable diseases (VPD) in vulnerable cohorts, such as immunocompromised patients. VPDs are associated with higher rates of adverse outcomes and substantial healthcare costs. This study assessed vaccination coverage amongst high-risk patients.
Methods
This retrospective study reviewed high-risk patients with a hospital encounter over six months (December 2024 to May 2025). High-risk patients were defined as patients with solid-organ and haematological malignancies, chronic respiratory conditions, human immunodeficiency virus (HIV), haemodialysis, and geriatric patients. Vaccination status was extracted from electronic medical records and the Australian immunisation Record (AIR). The primary outcome was up-to-date (UTD) vaccination status as per Australian Technical Advisory Group on Immunisation (ATAGI) guidelines. Recent hospital-acquired VPD outbreaks were also reviewed.
Results
Of 132 patients across seven high-risk cohorts, 8.3% (n=11) were UTD with vaccinations. Completion of the primary course of Covid-19 vaccination was high (96.9%), however subsequent booster coverage was substantially lower (10.7%). Vaccination coverage was lowest for HPV (6.7%) and pneumococcal (15.2%) vaccines and highest for diptheria-tetanus-pertussis vaccines (85%). Vaccination coverage was highest in antenatal (20%) and respiratory (15%) patients and lowest amongst oncology (0%), haematology (0%), renal (0%) or HIV (0%) patients. Two inpatient COVID-19 outbreaks involving 45 exposed patients resulted in 12 secondary cases. 2% (n=1) of patients were UTD with vaccinations.
Conclusion
This study revealed alarmingly low vaccination rates amongst vulnerable patients, highlighting the need for proactive and integrated vaccine delivery strategies. Addressing these gaps could significantly reduce VPD-related morbidity, avoidable hospitalisations, and hospital-associated outbreaks.