tetano
Editor, Senior Moderator
J Infect Dis
. 2023 Nov 29:jiad539.
doi: 10.1093/infdis/jiad539. Online ahead of print. Effectiveness of maternal influenza vaccination during pregnancy against laboratory-confirmed seasonal influenza among infants under 6 months of age in Ontario, Canada
Deshayne B Fell[SUP] 1 2 3 [/SUP], Margaret Russell[SUP] 4 [/SUP], Stephen G Fung[SUP] 2 [/SUP], Sarah Swayze[SUP] 3 [/SUP], Hannah Chung[SUP] 3 [/SUP], Sarah A Buchan[SUP] 3 5 6 7 [/SUP], Weston Roda[SUP] 8 [/SUP], Christa Smolarchuk[SUP] 9 [/SUP], Kumanan Wilson[SUP] 10 11 12 [/SUP], Natasha Crowcroft[SUP] 13 [/SUP], Kevin L Schwartz[SUP] 3 5 6 14 [/SUP], Jonathan B Gubbay[SUP] 5 15 16 17 [/SUP], Allison McGeer[SUP] 6 15 18 [/SUP], Marek Smieja[SUP] 19 [/SUP], David C Richardson[SUP] 20 21 [/SUP], Kevin Katz[SUP] 15 22 23 [/SUP], George Zahariadis[SUP] 24 [/SUP], Aaron Campigotto[SUP] 15 25 [/SUP], Samira Mubareka[SUP] 15 26 [/SUP], Dayre McNally[SUP] 27 28 [/SUP], Timothy Karnauchow[SUP] 27 29 [/SUP], Nathan Zelyas[SUP] 30 31 [/SUP], Lawrence W Svenson[SUP] 9 32 33 34 [/SUP], Jeffrey C Kwong[SUP] 3 5 6 35 36 [/SUP]
Affiliations
Background: Randomized trials conducted in low- and middle-income settings demonstrated efficacy of influenza vaccination during pregnancy against influenza infection among infants <6 months of age. However, vaccine effectiveness (VE) estimates from settings with different population characteristics and influenza seasonality remain limited.
Methods: We conducted a test-negative study in Ontario, Canada. All influenza virus tests among infants <6 months from 2010-2019 were identified and linked with health databases to ascertain information on maternal-infant dyads. VE was estimated from the odds ratio for influenza vaccination during pregnancy among cases versus controls, computed using logistic regression with adjustment for potential confounders.
Results: Among 23,806 infants tested for influenza, 1,783 (7.5%) were positive and 1,708 (7.2%) were born to mothers vaccinated against influenza during pregnancy. VE against laboratory-confirmed infant influenza infection was 64% (95% confidence interval [CI]: 50%-74%). VE was similar by trimester of vaccination (1st/2nd: 66%, 40%-80%; 3rd: 63%, 46%-74%), infant age at testing (0-<2 months: 63%, 46%-75%; 2-<6 months: 64%, 36%-79%), and gestational age at birth (≥37 weeks: 64%, 50%-75%; < 37 weeks: 61%, 4%-86%). VE against influenza hospitalization was 67% (95%CI: 50%-78%).
Conclusions: Influenza vaccination during pregnancy offers effective protection to infants <6 months, for whom vaccines are not currently available.
Keywords: effectiveness; influenza; pregnancy; vaccination.
. 2023 Nov 29:jiad539.
doi: 10.1093/infdis/jiad539. Online ahead of print. Effectiveness of maternal influenza vaccination during pregnancy against laboratory-confirmed seasonal influenza among infants under 6 months of age in Ontario, Canada
Deshayne B Fell[SUP] 1 2 3 [/SUP], Margaret Russell[SUP] 4 [/SUP], Stephen G Fung[SUP] 2 [/SUP], Sarah Swayze[SUP] 3 [/SUP], Hannah Chung[SUP] 3 [/SUP], Sarah A Buchan[SUP] 3 5 6 7 [/SUP], Weston Roda[SUP] 8 [/SUP], Christa Smolarchuk[SUP] 9 [/SUP], Kumanan Wilson[SUP] 10 11 12 [/SUP], Natasha Crowcroft[SUP] 13 [/SUP], Kevin L Schwartz[SUP] 3 5 6 14 [/SUP], Jonathan B Gubbay[SUP] 5 15 16 17 [/SUP], Allison McGeer[SUP] 6 15 18 [/SUP], Marek Smieja[SUP] 19 [/SUP], David C Richardson[SUP] 20 21 [/SUP], Kevin Katz[SUP] 15 22 23 [/SUP], George Zahariadis[SUP] 24 [/SUP], Aaron Campigotto[SUP] 15 25 [/SUP], Samira Mubareka[SUP] 15 26 [/SUP], Dayre McNally[SUP] 27 28 [/SUP], Timothy Karnauchow[SUP] 27 29 [/SUP], Nathan Zelyas[SUP] 30 31 [/SUP], Lawrence W Svenson[SUP] 9 32 33 34 [/SUP], Jeffrey C Kwong[SUP] 3 5 6 35 36 [/SUP]
Affiliations
- PMID: 38029414
- DOI: 10.1093/infdis/jiad539
Background: Randomized trials conducted in low- and middle-income settings demonstrated efficacy of influenza vaccination during pregnancy against influenza infection among infants <6 months of age. However, vaccine effectiveness (VE) estimates from settings with different population characteristics and influenza seasonality remain limited.
Methods: We conducted a test-negative study in Ontario, Canada. All influenza virus tests among infants <6 months from 2010-2019 were identified and linked with health databases to ascertain information on maternal-infant dyads. VE was estimated from the odds ratio for influenza vaccination during pregnancy among cases versus controls, computed using logistic regression with adjustment for potential confounders.
Results: Among 23,806 infants tested for influenza, 1,783 (7.5%) were positive and 1,708 (7.2%) were born to mothers vaccinated against influenza during pregnancy. VE against laboratory-confirmed infant influenza infection was 64% (95% confidence interval [CI]: 50%-74%). VE was similar by trimester of vaccination (1st/2nd: 66%, 40%-80%; 3rd: 63%, 46%-74%), infant age at testing (0-<2 months: 63%, 46%-75%; 2-<6 months: 64%, 36%-79%), and gestational age at birth (≥37 weeks: 64%, 50%-75%; < 37 weeks: 61%, 4%-86%). VE against influenza hospitalization was 67% (95%CI: 50%-78%).
Conclusions: Influenza vaccination during pregnancy offers effective protection to infants <6 months, for whom vaccines are not currently available.
Keywords: effectiveness; influenza; pregnancy; vaccination.