Recent epidemiology of pertussis in Europe has showed adults now represent a major proportion of cases. Yet, in most countries, the disease is largely under-recognized in adults and its burden is not well understood. We aimed to estimate the incidence of hospitalized pertussis among adults in France in recent years.
This retrospective cohort study among French residents ?18 years-old over 2008-2020 used the French healthcare claims database (SNDS). Hospitalized pertussis cases were identified by ICD-10 codes A37, stratified by age and presence of asthma and/or chronic obstructive pulmonary disease (COPD) algorithmically captured using drug dispensations, diagnoses, and long-term disease status. Cumulative incidences were estimated against census data and an age and sex representative SNDS sample for people with chronic conditions. Negative binomial regression was used to compare incidences adjusted on the cyclical pattern of pertussis.
Over 2008-2020, 3681 cases of pertussis were hospitalized, including 953 (25.9%) who required intensive care or died. Epidemic peaks were detected in 2009, 2012/13, and 2017/18, with an overall declining trend in incidence.
| Cases (n) | Cumulative incidence (per 100,000 p.) | Adjusted Incidence Ratio (95% Confidence Interval) | |
| Age | |||
| 18-25 | 270 | 0.3 | Ref |
| 26-49 | 1131 | 0.4 | 1.3 (1.1-1.5) |
| 50-64 | 797 | 0.5 | 1.5 (1.3-1.7) |
| ?65 | 1483 | 1.0 | 3.1 (2.7-3.5) |
| Asthma and/or COPD | |||
| No | 1384 | 0.2 | Ref |
| Yes | 2297 | 3.9 | 18.6 (17.4-19.9) |
Hospitalizations for pertussis among adults declined over the pre-COVID19 decade, possibly due to increasing uptake of adult pertussis vaccines. Yet, pertussis continues to exert burden on adults, with older age and asthma and/or COPD representing significant risk factors.