Incremental effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia hospitalisation among Australian Indigenous children: A record linkage study

Alamgir Kabir; Deborah Randall; Anthony T Newall; Hannah C Moore; Sanjay Jayasinghe; Parveen Fathima; Bette Liu; Peter McIntyre; Heather F Gidding

doi:10.1016/j.vaccine.2023.07.042

Incremental effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia hospitalisation among Australian Indigenous children: A record linkage study

Vaccine. 2023 Aug 23;41(37):5454-5460. doi: 10.1016/j.vaccine.2023.07.042. Epub 2023 Jul 26.

Authors

Alamgir Kabir¹, Deborah Randall², Anthony T Newall³, Hannah C Moore⁴, Sanjay Jayasinghe⁵, Parveen Fathima⁶, Bette Liu³, Peter McIntyre⁷, Heather F Gidding⁸

Affiliations

¹ School of Population Health, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia; The University of Sydney Northern Clinical School, NSW, Australia; Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia; Centre for Primary Health Care and Equity, University of New South Wales, Sydney, NSW, Australia. Electronic address: a.kabir@unsw.edu.au.
² The University of Sydney Northern Clinical School, NSW, Australia; Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia.
³ School of Population Health, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
⁴ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, WA, Australia; School of Population Health, Curtin University, Perth, Western, Australia.
⁵ National Centre for Immunisation Research and Surveillance, Westmead, NSW, Australia; Discipline of Child and Adolescent Health, Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, University of Sydney, Australia.
⁶ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, WA, Australia; Sydney School of Public Health, Faculty of Medicine and Health, University of Sydney, Australia.
⁷ National Centre for Immunisation Research and Surveillance, Westmead, NSW, Australia.
⁸ School of Population Health, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia; The University of Sydney Northern Clinical School, NSW, Australia; Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia; National Centre for Immunisation Research and Surveillance, Westmead, NSW, Australia; Sydney School of Public Health, Faculty of Medicine and Health, University of Sydney, Australia.

PMID: 37507273
DOI: 10.1016/j.vaccine.2023.07.042

Abstract

Background: The impact of pneumococcal conjugate vaccines (PCVs) on pneumonia in children is well-documented but data on 23-valent pneumococcal polysaccharide vaccine (PPV23) are lacking. Between 2001 and 2011, Indigenous children in Western Australia (WA) were recommended to receive PPV23 at 18-24 months of age following 3 doses of 7-valent PCV. We evaluated the incremental effectiveness of PPV23 against pneumonia hospitalisation.

Methods: Indigenous children born in WA between 2001 and 2012 who received PCV dose 3 by 12 months of age were followed from 18 to 60 months of age for the first episode of pneumonia hospitalisation (all-cause and 3 subgroups: presumptive pneumococcal, other specified causes, and unspecified). We used Cox regression modelling to estimate hazard ratios (HRs) for pneumonia hospitalisation among children who had, versus had not, received PPV23 between 18 and 30 months of age after adjustment for confounders.

Results: 11,120 children had 327 first episodes of all-cause pneumonia hospitalisation, with 15 (4.6%) coded as presumptive pneumococcal, 46 (14.1%) as other specified causes and 266 (81.3%) unspecified. No statistically significant reduction in all-cause pneumonia was seen with PPV23 (HR 1.11; 95% CI: 0.87-1.43), but the direction of the association differed for presumptive pneumococcal (HR 0.47; 95% CI: 0.16-1.35) and specified (HR 0.89; 95% CI: 0.49-1.62) from unspecified causes (HR 1.13; 95% CI: 0.86-1.49). During the baseline period before PPV23 vaccination (12-18 months), all-cause pneumonia risk was higher among PPV23-vaccinated than unvaccinated children (RR: 1.73; 95% CI: 1.30-2.28).

Conclusion: In this high-risk population, no statistically significant incremental effect of a PPV23 booster at 18-30 months was observed against hospitalised all-cause pneumonia or the more specific outcome of presumptive pneumococcal pneumonia. Confounding by indication may explain the slight trend towards an increased risk against all-cause pneumonia. Larger studies with better control of confounding are needed to further inform PPV23 vaccination.

Keywords: Data linkage; Indigenous; Pneumococcal polysaccharide vaccine; Pneumonia; Vaccine effectiveness.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Australia
Child
Child, Preschool
Hospitalization
Humans
Infant
Pneumococcal Infections* / epidemiology
Pneumococcal Infections* / prevention & control
Pneumococcal Vaccines
Pneumonia, Pneumococcal* / epidemiology
Pneumonia, Pneumococcal* / prevention & control
Streptococcus pneumoniae
Vaccines, Conjugate / therapeutic use

Substances

Pneumococcal Vaccines
Vaccines, Conjugate