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. Author manuscript; available in PMC: 2026 Apr 18.
Published in final edited form as: Vaccine. 2025 Nov 1;68:127887. doi: 10.1016/j.vaccine.2025.127887

Table 2. Pregnant and infant cohorts experiencing the greatest combined overlap with the 2022/23 influenza vaccination campaign and different influenza season categories.

Cohorts with the greatest reported overlap are those whose (i) pregnancy periods overlapped with at least 50% of the 2022/23 vaccination campaign and at least 50% of the respective influenza season (column 2); (ii) pre-pregnancy periods overlapped with at least 50% of the 2022/23 vaccination campaign and pregnancy periods overlapped with at least 50% of the respective influenza season (column 3); or (iii) periods in utero overlapped with at least 50% of the 2022/23 vaccination campaign and infancy periods overlapped with at least 50% of the respective influenza season (column 4). Rows are ordered by peak season timing, from earliest to latest.

Season category Pregnancy start months with
greatest combined overlap: (i)
vaccination during pregnancy		 Pregnancy start months with
greatest combined overlap: (ii)
pre-pregnancy vaccination		 Infant birth months with greatest
combined overlap: (iii) vaccination
while in utero
2022/23 March 2022 – October 2022 November 2022 – December 2022 November 2022 – December 2022
Early (pre-COVID) April 2022 – October 2022 November 2022 – January 2023 November 2022 – January 2023
Late (pre-COVID) May 2022 – October 2022 November 2022 – February 2023 November 2022 – February 2023
2021/22 June 2022 – October 2022 November 2022 – March 2023 November 2022 – March 2023