TY - JOUR
T1 - Non-specific benefit of seasonal influenza vaccine on respiratory syncytial virus-hospitalisations in children
T2 - An instrumental variable approach using population-based data
AU - Le, Huong
AU - de Klerk, Nicholas
AU - Blyth, Christopher C.
AU - Gidding, Heather
AU - Fathima, Parveen
AU - Moore, Hannah C.
N1 - Funding Information:
The authors wish to thank the staff at the Western Australian Data Linkage Branch, the Australian Institute of Health and Welfare, and the custodians of the Western Australian Registry of Births, Deaths and Marriages, the Hospital Morbidity Data Collection, the Midwives Notification System and the PathWest Laboratory Medicine respiratory dataset. We thank people of Western Australia, whose data is being used for this project. This study was funded by a Wesfarmers Centre for Vaccines and Infectious Diseases Seed Grant, and the Future Health Research and Innovation Fund through the WA Near-Miss Awards Program (awarded to HCM). Data acquisition was part of a larger study funded by the Population Health Research Network Proof of Concept Project, a capability of the Commonwealth Government Collaborative Research Infrastructure Strategy and Education Investment Fund Super Science Initiative, and the Australian National Health and Medical Research Council (project grant GNT1082342). HCM is supported by a Stan Perron Charitable Foundation and has received further funding from the Future Health Research and Innovation Fund through the WA Near-miss Awards program. CCB is supported by the National Health and Medical Research Council Fellowships (APP1111596 & APP1173163). The funders had no role in study design, data collection, data analysis, data interpretation, or writing of the report.
Funding Information:
The authors wish to thank the staff at the Western Australian Data Linkage Branch, the Australian Institute of Health and Welfare, and the custodians of the Western Australian Registry of Births, Deaths and Marriages, the Hospital Morbidity Data Collection, the Midwives Notification System and the PathWest Laboratory Medicine respiratory dataset. We thank people of Western Australia, whose data is being used for this project. This study was funded by a Wesfarmers Centre for Vaccines and Infectious Diseases Seed Grant, and the Future Health Research and Innovation Fund through the WA Near-Miss Awards Program (awarded to HCM). Data acquisition was part of a larger study funded by the Population Health Research Network Proof of Concept Project , a capability of the Commonwealth Government Collaborative Research Infrastructure Strategy and Education Investment Fund Super Science Initiative , and the Australian National Health and Medical Research Council (project grant GNT1082342 ). HCM is supported by a Stan Perron Charitable Foundation and has received further funding from the Future Health Research and Innovation Fund through the WA Near-miss Awards program. CCB is supported by the National Health and Medical Research Council Fellowships ( APP1111596 & APP1173163 ). The funders had no role in study design, data collection, data analysis, data interpretation, or writing of the report.
Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/7/31
Y1 - 2023/7/31
N2 - Background: Seasonal influenza vaccine is effective against influenza hospitalisations, but little is known about non-specific effects of the vaccine on other respiratory pathogens with similar seasonal patterns. We aimed to assess the causal impact of seasonal influenza vaccine on laboratory-confirmed hospitalisations for respiratory syncytial virus (RSV) in children using an instrumental variable (IV) strategy. Methods: We used probabilistically linked population-based data on childhood immunisations, births, deaths, hospitalisations, perinatal factors, and microbiology test results (2000–2013) of all Western Australian (WA) children born 2000–2012, observed longitudinally until the earliest of 7 years of age or 31 December 2013. We exploited a unique natural experiment created from the WA's state-funded preschool influenza vaccination policy commencing in 2008 and used this as an instrument for children's seasonal influenza vaccination status. We estimated a system of two simultaneous probit equations: determinants of influenza vaccine uptake, and determinants of RSV-confirmed hospitalisation. Results: Influenza vaccine coverage was low prior to 2008 but increased to 36 % in children aged 6–23 months in 2009. The majority (90 %) of RSV-hospitalisations occurred in children <2 years. Receipt of influenza vaccine reduced RSV-hospitalisations, especially in those <2 years with a rate reduction of 2.27 per 1000 (95 % CI: −3.26; −1.28), and a smaller rate reduction of 0.53 per 1000 (95 % CI: −1.04; −0.02) in those 2–7 years. Over the 5-year period (2008–2013), the state-funded preschool-influenza vaccine program resulted in 1,193 fewer RSV-hospitalisations. Of these, 793 (67 %) were in young children <2 years. Conclusions: To our knowledge, this is the first analysis utilising an IV estimation strategy on a population level to assess the causal impact of seasonal influenza vaccine on risk of RSV-hospitalisations. We estimated a small protective effect that warrants further investigation.
AB - Background: Seasonal influenza vaccine is effective against influenza hospitalisations, but little is known about non-specific effects of the vaccine on other respiratory pathogens with similar seasonal patterns. We aimed to assess the causal impact of seasonal influenza vaccine on laboratory-confirmed hospitalisations for respiratory syncytial virus (RSV) in children using an instrumental variable (IV) strategy. Methods: We used probabilistically linked population-based data on childhood immunisations, births, deaths, hospitalisations, perinatal factors, and microbiology test results (2000–2013) of all Western Australian (WA) children born 2000–2012, observed longitudinally until the earliest of 7 years of age or 31 December 2013. We exploited a unique natural experiment created from the WA's state-funded preschool influenza vaccination policy commencing in 2008 and used this as an instrument for children's seasonal influenza vaccination status. We estimated a system of two simultaneous probit equations: determinants of influenza vaccine uptake, and determinants of RSV-confirmed hospitalisation. Results: Influenza vaccine coverage was low prior to 2008 but increased to 36 % in children aged 6–23 months in 2009. The majority (90 %) of RSV-hospitalisations occurred in children <2 years. Receipt of influenza vaccine reduced RSV-hospitalisations, especially in those <2 years with a rate reduction of 2.27 per 1000 (95 % CI: −3.26; −1.28), and a smaller rate reduction of 0.53 per 1000 (95 % CI: −1.04; −0.02) in those 2–7 years. Over the 5-year period (2008–2013), the state-funded preschool-influenza vaccine program resulted in 1,193 fewer RSV-hospitalisations. Of these, 793 (67 %) were in young children <2 years. Conclusions: To our knowledge, this is the first analysis utilising an IV estimation strategy on a population level to assess the causal impact of seasonal influenza vaccine on risk of RSV-hospitalisations. We estimated a small protective effect that warrants further investigation.
KW - Causal inference
KW - Children
KW - Instrumental variable
KW - Quasi-natural experiment
KW - RSV infections
KW - Seasonal influenza vaccine
UR - http://www.scopus.com/inward/record.url?scp=85164317608&partnerID=8YFLogxK
U2 - 10.1016/j.vaccine.2023.06.085
DO - 10.1016/j.vaccine.2023.06.085
M3 - Article
C2 - 37407408
AN - SCOPUS:85164317608
SN - 0264-410X
VL - 41
SP - 5029
EP - 5036
JO - Vaccine
JF - Vaccine
IS - 34
ER -