Table 2. Summary of published vaccine effectiveness estimates (interim or final) against medically attended influenza, Australia and Canada, seasons 2014 to 2020.

Season (references)	Australia VE estimate (95% CI)	Canada VE estimate (95% CI)	Notes on VE estimatea
2014/2014–2015 ((20,21)	44% (31–55)	9% (−14 –57)	VE against medically attended influenza (all types)
2015/2015–2016 ((22,23))	54% (42–63)	46% (32–57)	VE against medically attended influenza (all types)
2016/2016–2017 ((24,25))	40% (18–56)	44% (30–55)	VE against medically attended influenza (all types)
2017/2017–2018 ((26,27))	55% (17–46)	42% (25–55)	Interim VE against medically attended influenza (all types)
2018/2018–2019b (28,29)	68% (47–67)	68% (55–77)	Interim VE against medically attended influenza (all types)
2019/2019–2020c (30,31)	A(H1N1): 62% (39–78) A(H3N2): 37% (24–49) B: 63% (45–74)	A(H1N1): 44% (26–58) A(H3N2): 62% (37–77) B: 69% (57–77)	Interim VE against medically attended influenza (by type/subtype)
2020/2020–2021d	N/A	N/A	N/A

Abbreviations: CI, confidence interval; N/A, not applicable; VE, vaccine effectiveness

^a The most up-to-date comparable estimates available were used: If only interim estimates were available for one country, the interim estimates for both countries were used for the comparison

^b The 2018 Southern Hemisphere and 2018–2019 Northern Hemisphere vaccine had a different influenza B Victoria component

^c The 2019 Southern Hemisphere and 2019–2020 Northern Hemisphere vaccine had different influenza A(H1N1) and A(H3N2) components

^d The 2020 Southern Hemisphere and the 2020–2021 Northern Hemisphere vaccine had different influenza A(H1N1) and A(H3N2) components