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Jayasundara D, Randall D, Sheridan S, Sheppeard V, Liu B, Richmond PC, Blyth CC, Wood JG, Moore HC, McIntyre PB, Gidding HF. Estimating the excess burden of pertussis disease in Australia within the first year of life, that might have been prevented through timely vaccination. Int J Epidemiol 2022; 52:250-259. [PMID: 36099159 PMCID: PMC9908038 DOI: 10.1093/ije/dyac175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 08/29/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Previous Australian studies have shown that delayed vaccination with each of the three primary doses of diphtheria-tetanus-pertussis-containing vaccines (DTP) is up to 50 % in certain subpopulations. We estimated the excess burden of pertussis that might have been prevented if (i) all primary doses and (ii) each dose was given on time. METHODS Perinatal, immunization, pertussis notification and death data were probabilistically linked for 1 412 984 infants born in two Australian states in 2000-12. A DTP dose administered >15 days after the recommended age was considered delayed. We used Poisson regression models to compare pertussis notification rates to 1-year of age in infants with ≥1 dose delayed (Aim 1) or any individual dose delayed (Aim 2) versus a propensity weighted counterfactual on-time cohort. RESULTS Of all infants, 42% had ≥1 delayed DTP dose. We estimated that between 39 to 365 days of age, 85 (95% CI: 61-109) cases per 100 000 infants, could have been prevented if all infants with ≥1 delayed dose had received their three doses within the on-time window. Risk of pertussis was higher in the delayed versus the on-time cohort, so crude rates overestimated the excess burden (110 cases per 100 000 infants (95% CI: 95-125)). The estimated dose-specific excess burden per 100 000 infants was 132 for DTP1, 50 for DTP2 and 19 for DTP3. CONCLUSIONS We provide robust evidence that improved DTP vaccine timeliness, especially for the first dose, substantially reduces the burden of infant pertussis. Our methodology, using a potential outcomes framework, is applicable to other settings.
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Affiliation(s)
- Duleepa Jayasundara
- NSW Biostatistics Training Program, NSW Ministry of Health, St Leonards, NSW, Australia,Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia,University of Sydney, Northern Clinical School, St Leonards, NSW, Australia
| | - Deborah Randall
- Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia,University of Sydney, Northern Clinical School, St Leonards, NSW, Australia
| | - Sarah Sheridan
- Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia,University of Sydney, Northern Clinical School, St Leonards, NSW, Australia,National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Sydney, NSW, Australia
| | - Vicky Sheppeard
- Public Health Unit, South Eastern Sydney Local Health District, Sydney, NSW, Australia,School of Public Health, University of Sydney, Sydney, NSW, Australia
| | - Bette Liu
- National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Sydney, NSW, Australia,School of Population Health, UNSW Medicine, UNSW, Sydney, NSW, Australia
| | - Peter C Richmond
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA, Australia,Department of General Paediatrics, Perth Children's Hospital, Perth, WA, Australia,School of Medicine, University of Western Australia, Perth, WA, Australia
| | - Christopher C Blyth
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA, Australia,School of Medicine, University of Western Australia, Perth, WA, Australia,Department of Infectious Diseases, Perth Children's Hospital, Perth, WA, Australia,Department of Microbiology, PathWest Laboratory Medicine WA, Perth Children's Hospital, Perth, WA, Australia
| | - James G Wood
- School of Population Health, UNSW Medicine, UNSW, Sydney, NSW, Australia
| | - Hannah C Moore
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
| | - Peter B McIntyre
- National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Sydney, NSW, Australia,Department of Women’s and Children’s Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Heather F Gidding
- Corresponding author. Women and Babies Research, Level 5, Douglas Building, Royal North, Shore Hospital, St Leonards, NSW 2065, Australia. E-mail:
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