Severe Invasive Pneumococcal Disease Caused by Serotype 19A in Children Under Five Years in Tāmaki Makaurau Auckland, Aotearoa New Zealand

Abstract

Background: Increases in childhood invasive pneumococcal disease (IPD) have been reported in several countries following the easing of COVID-19 pandemic mitigations. In Aotearoa New Zealand (AoNZ), a surge in IPD is occurring in young children concurrent with changes in pneumococcal vaccines and declining immunization coverage. We sought to examine epidemiologic and clinical features of IPD among children under 5 years in a large urban region of AoNZ in the 3 years post-COVID-19. Methods: Demographic, clinical and laboratory data were collated from children under 5 years with Streptococcus pneumoniae identified from normally sterile sites between January 1, 2021, and December 31, 2023, in Tāmaki Makaurau Auckland, AoNZ. Results: We identified 93 episodes of IPD (annual incidence of 18–40 cases per 100,000 population per year). Serotype was identified in 68 episodes and 46 (68%) were serotype 19A. Incidence was higher in Pacific children compared with non-Māori, non-Pacific children (incidence rate ratio: 2.3; 95% confidence interval: 1.4–3.7). Bacteremia occurred in 65 (70%) episodes, empyema in 47 (51%), meningitis in 11 (12%) and hemolytic uremic syndrome in 7 (7.5%). All cases of hemolytic uremic syndrome and empyema were only among children with serotype 19A. Two children died, both had serotype 19A, and 13/91 survivors (14%) experienced serious sequelae. Conclusions: The use of the pneumococcal conjugate vaccine with lower valency and easing of COVID-19 containment measures each may have contributed to an increase in IPD in AoNZ. Serotype 19A is associated with empyema and causes severe disease in young children. Urgent efforts are required to improve PCV13 coverage in AoNZ.