The Evolving Epidemiology of Paediatric Acute Mastoiditis in New Zealand
Authors List
Stevenson J., Auckland City Hospital, Auckland, NZ
Walls T., Hale S., Bird P., Christchurch Hospital, Christchurch, NZ
Rowlands S., Dunedin Hospital, Dunedin, NZ
Kong L., Waikato Hospital, Hamilton, NZ
Keren B., Wellington Hospital, Wellington, NZ
Introduction
The global incidence of paediatric acute mastoiditis (AM) decreased following the introduction of Pneumococcal Conjugate (PCV) vaccines. In 2017, PCV-13 was replaced by PCV-10 in the New Zealand immunisation schedule. We hypothesised that this policy change would result in an increased incidence of paediatric AM in New Zealand.
Aims
To evaluate the impact of the changes in Pneumococcal vaccination on the epidemiology of paediatric AM in New Zealand.
Methods
A retrospective observational study was conducted, including patients aged <18 years admitted with an ICD-10 diagnosis of AM between January 1, 2014 and December 31, 2022. Cases were identified from the National Minimum Dataset. Electronic medical records were reviewed for cases in Auckland, Waikato, Wellington, Christchurch and Dunedin. Cases were divided into four periods, 2014-2016 (PCV-13 baseline), 2017-2019 (transition), 2020-2021 (PCV-10 COVID) and 2022 (PCV-10 post-COVID) for analysis. In each period the incidence of all-cause AM, the proportion of AM cases attributable to Pneumococcus and the proportion of Pneumococcal AM cases presenting with a subperiosteal abscess were compared with the baseline period.
Results
391 cases of AM occurred during the study period. The national incidence of paediatric AM increased from a baseline of 3.62 cases/100,000 person-years in 2014-2016 to 6.22 cases/100,000 person-years in 2022 (RR 1.72, 95% CI 1.28-2.30). Data was available for 212 cases admitted in Auckland, Waikato, Wellington, Christchurch and Dunedin. In 2022 48% of cases were attributed to Pneumococcus, compared with 27% in the baseline period (p = 0.03). In 2022 17/20 (85%) of Pneumococcal cases presented with a sub-periosteal abscess, compared with 7/18 (39%) of Pneumococcal cases in the baseline period (p <0.01).
Conclusion
The national incidence of paediatric AM in New Zealand increased after the national immunisation schedule reverted from PCV-13 to PCV-10, with a concurrent increase in the proportion of cases attributable to Pneumococcus.
Stevenson J., Auckland City Hospital, Auckland, NZ
Walls T., Hale S., Bird P., Christchurch Hospital, Christchurch, NZ
Rowlands S., Dunedin Hospital, Dunedin, NZ
Kong L., Waikato Hospital, Hamilton, NZ
Keren B., Wellington Hospital, Wellington, NZ
Introduction
The global incidence of paediatric acute mastoiditis (AM) decreased following the introduction of Pneumococcal Conjugate (PCV) vaccines. In 2017, PCV-13 was replaced by PCV-10 in the New Zealand immunisation schedule. We hypothesised that this policy change would result in an increased incidence of paediatric AM in New Zealand.
Aims
To evaluate the impact of the changes in Pneumococcal vaccination on the epidemiology of paediatric AM in New Zealand.
Methods
A retrospective observational study was conducted, including patients aged <18 years admitted with an ICD-10 diagnosis of AM between January 1, 2014 and December 31, 2022. Cases were identified from the National Minimum Dataset. Electronic medical records were reviewed for cases in Auckland, Waikato, Wellington, Christchurch and Dunedin. Cases were divided into four periods, 2014-2016 (PCV-13 baseline), 2017-2019 (transition), 2020-2021 (PCV-10 COVID) and 2022 (PCV-10 post-COVID) for analysis. In each period the incidence of all-cause AM, the proportion of AM cases attributable to Pneumococcus and the proportion of Pneumococcal AM cases presenting with a subperiosteal abscess were compared with the baseline period.
Results
391 cases of AM occurred during the study period. The national incidence of paediatric AM increased from a baseline of 3.62 cases/100,000 person-years in 2014-2016 to 6.22 cases/100,000 person-years in 2022 (RR 1.72, 95% CI 1.28-2.30). Data was available for 212 cases admitted in Auckland, Waikato, Wellington, Christchurch and Dunedin. In 2022 48% of cases were attributed to Pneumococcus, compared with 27% in the baseline period (p = 0.03). In 2022 17/20 (85%) of Pneumococcal cases presented with a sub-periosteal abscess, compared with 7/18 (39%) of Pneumococcal cases in the baseline period (p <0.01).
Conclusion
The national incidence of paediatric AM in New Zealand increased after the national immunisation schedule reverted from PCV-13 to PCV-10, with a concurrent increase in the proportion of cases attributable to Pneumococcus.
