Infant, maternal and demographic predictors of delayed vaccination: A population-based cohort study

Heather F Gidding; Lloyd K Flack; Sarah Sheridan; Bette Liu; Parveen Fathima; Vicky Sheppeard; Peter Richmond; Brynley Hull; Christopher Blyth; Ross M Andrews; Thomas L Snelling; Nicholas de Klerk; Peter B McIntyre; Hannah C Moore; ACIR linkage Investigator Team

doi:10.1016/j.vaccine.2019.09.091

Infant, maternal and demographic predictors of delayed vaccination: A population-based cohort study

Vaccine. 2020 Aug 27;38(38):6057-6064. doi: 10.1016/j.vaccine.2019.09.091. Epub 2019 Oct 15.

Authors

Collaborators

ACIR linkage Investigator Team:
H Gidding, H Moore, P McIntyre, N de Klerk, B Liu, C Blyth, T Snelling, K Edmond, L Jorm, P Effler, P Richmond, R Menzies, R Andrews, T Joseph, V Sheppeard, B Hull, S Sheridan, P Fathima

Affiliations

¹ Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia; The University of Sydney Northern Clinical School, NSW, Australia; National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Sydney, NSW, Australia; School of Public Health and Community Medicine, UNSW Medicine, University of NSW, Sydney, NSW, Australia. Electronic address: heather.gidding@sydney.edu.au.
² School of Public Health and Community Medicine, UNSW Medicine, University of NSW, Sydney, NSW, Australia.
³ Women and Babies Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia; The University of Sydney Northern Clinical School, NSW, Australia; National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Sydney, NSW, Australia; School of Public Health and Community Medicine, UNSW Medicine, University of NSW, Sydney, NSW, Australia.
⁴ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia.
⁵ Communicable Diseases Branch, Health Protection NSW, Sydney, NSW, Australia.
⁶ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia; Perth Children's Hospital, WA, Australia; School of Medicine, University of Western Australia, Perth, WA, Australia.
⁷ National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Sydney, NSW, Australia.
⁸ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia; Perth Children's Hospital, WA, Australia; School of Medicine, University of Western Australia, Perth, WA, Australia; Department of Microbiology, PathWest Laboratory Medicine WA, Perth Children's Hospital, Perth, WA, Australia.
⁹ Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia; National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australian Capital Territory, Australia.
¹⁰ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia; Perth Children's Hospital, WA, Australia; Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia; School of Public Health, Curtin University, Perth, WA, Australia.

PMID: 31628032
DOI: 10.1016/j.vaccine.2019.09.091

Abstract

Background: Receiving vaccines at or close to their due date (vaccination timeliness) is a now key measure of program performance. However, studies comprehensively examining predictors of delayed infant vaccination are lacking. We aimed to identify predictors of short and longer-term delays in diphtheria-tetanus-pertussis (DTP) vaccination by dose number and ethnicity.

Methods: Perinatal, notification, death and immunisation databases were linked for 1.3 million births in 2000-11 from two Australian states (Western Australia and New South Wales), with follow-up data until 2013. Ordinal logistic regression was used to estimate adjusted relative risks (RR) by degree of delay. Separate models were constructed for each vaccine dose and for Aboriginal and non-Aboriginal children.

Results: Each dose-specific cohort included at least 49,000 Aboriginal and 1.1 million non-Aboriginal children. Delayed receipt was more common among Aboriginal than non-Aboriginal children (eg for the first dose of DTP [DTP1] 19.4 v 8.1%). Risk factors for delayed vaccination were strongest for DTP1, and delayed receipt of DTP1 was a key driver of subsequent delays; every week DTP1 was delayed was associated with a 1.6 to 2-fold increased risk of delayed DTP2 receipt. For DTP1, ≥3 previous pregnancies (the only factor more strongly associated with longer than shorter delays; RR ≥5 compared to no previous pregnancies), and children born to mothers <20 years of age (RR ≥2 compared to ≥35 years) were at highest risk of delay. Other independent predictors were prematurity, maternal smoking during pregnancy, and being born in Western Australia (if Aboriginal) or another country in the Oceania region.

Conclusion: The sub-populations at risk for delayed vaccination we have identified are likely generalisable to other high-income settings. Measures to improve their dose 1 timeliness, particularly for children with older siblings, are likely to have significant flow-on benefits for timeliness of later doses.

Keywords: Data linkage; Diphtheria-tetanus-pertussis vaccine; Population; Vaccine timeliness.

Publication types

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

MeSH terms

Adult
Australia / epidemiology
Child
Cohort Studies
Diphtheria-Tetanus-Pertussis Vaccine*
Female
Humans
Immunization Schedule
Infant
New South Wales
Pregnancy
Vaccination*
Western Australia

Substances

Diphtheria-Tetanus-Pertussis Vaccine