1481. Incidence of Pertussis in Older Adults in England and the United Kingdom: A Large, Retrospective Database Analysis

BACKGROUND: Pertussis affects people of all ages and can lead to severe complications in adults, including hospitalization. Pertussis immunity, whether vaccine-induced or from natural infection, wanes over time. Therefore, despite extensive pediatric vaccination against pertussis, adults remain susceptible to the disease. Here we present the reported incidence of pertussis in people ≥ 50 years old (≥ 50yo) in England and the United Kingdom (UK). METHODS: We performed an observational, retrospective database analysis using the UK Clinical Practice Research Datalink GOLD and Aurum primary care databases, and Hospital Episode Statistics database when available for English subjects (HES-Eng), 2009-2018. Occurrence of pertussis was identified by diagnostic codes recorded in primary care only for the UK subset, and primary care and/or secondary care for HES-Eng. RESULTS: In the ≥ 50yo UK population, a total of 47.1 million (m) person-years of follow-up (PYFU) including 28.5m PYFU for HES-Eng, were included. In the UK, the pertussis Incidence Rate (IR) across all years was 5.44 per 100,000 PYFU. Yearly IRs ranged from 0.79 – 11.40 per 100,000 PYFU and reflected the cyclic epidemiology of pertussis. A peak of IR was observed in 2012, known to be an outbreak year, and observed IRs were higher in 2013-2018 (4.75 – 9.73 per 100,000 PYFU) than 2009-2011 (0.79 – 1.48 per 100,000 PYFU). In the HES-Eng population, overall IR was 5.76 per 100,000 PYFU. IRs were highest in the younger age groups (HES-Eng: 8.88 in 50-54 yo; 1.42 in ≥ 85 yo) (see table 1 and 2). Table 1 [Image: see text] Table 2 [Image: see text] CONCLUSION: The observed reported IR of pertussis was similar in the UK and HES-Eng populations, noting the inclusion of secondary care diagnoses in the latter. The dynamics of IRs across years are consistent with estimated IRs from Public Health England data. Considering the burden of pertussis established elsewhere in older adults, and their non-negligible contribution to the whole population incidence, strategies for the prevention of pertussis should include this age group. DISCLOSURES: Emmanuel Aris, PhD, the GSK group of companies (Employee, Shareholder) Esse Ifebi Akpo, n/a, the GSK group of companies (Employee, Shareholder) Amit Bhavsar, MBBS, MHA, the GSK group of companies (Employee) Lauriane Harrington, n/a, the GSK group of companies (Employee) Evie Merinopoulou, MSc, Evidera Ltd (Employee)the GSK group of companies (Consultant) Nicola Sawalhi-Leckenby, MSc, Evidera Ltd (Employee)the GSK group of companies (Consultant) Elisa Turriani, PhD, the GSK group of companies (Employee) Kinga Meszaros, MBA, the GSK group of companies (Employee, Shareholder) Dimitra Lambrelli, PhD, MPharm, Evidera Ltd (Employee)the GSK group of companies (Consultant) Piyali Mukherjee, MBBS, MPH, the GSK group of companies (Employee, Shareholder)