tetano
Editor, Senior Moderator
Clin Infect Dis
. 2023 Oct 11:ciad627.
doi: 10.1093/cid/ciad627. Online ahead of print. Influenza hospitalization burden by subtype, age, comorbidity and vaccination status: 2012/13 to 2018/19 seasons, Quebec, Canada
Sara Carazo[SUP] 1 2 [/SUP], Charles-Antoine Guay[SUP] 1 2 3 4 [/SUP], Danuta M Skowronski[SUP] 5 [/SUP], Rachid Amini[SUP] 1 [/SUP], Hugues Charest[SUP] 6 7 [/SUP], Gaston De Serres[SUP] 1 2 8 [/SUP], Rodica Gilca[SUP] 1 2 8 [/SUP]
Affiliations
Background: Influenza immunization programs aim to reduce the risk and burden of severe outcomes. To inform optimal program strategies, we monitored influenza hospitalizations over seven seasons, stratified by age, comorbidity and vaccination status.
Methods: We assembled data from four hospitals involved in an active surveillance network with systematic collection of nasal samples and PCR testing for influenza virus in all patients admitted through the emergency department with acute respiratory infection during 2012/13 to 2018/19 influenza seasons in Quebec, Canada. We estimated seasonal, population-based incidence of influenza-associated hospitalizations by subtype predominance, age, comorbidity and vaccine status, and derived the number-needed-to-vaccinate to prevent one hospitalization per stratum.
Results: The average seasonal incidence of influenza-associated hospitalization was 89/100,000 (95%CI: 86, 93), lower during A(H1N1) (49-82/100,000) than A(H3N2) seasons (73-143/100,000). Overall risk followed a J-shaped age pattern, highest among infants 0-5 months and adults ≥75 years. Hospitalization risks were highest for children <5 years during A(H1N1) but for adults ≥75 years during A(H3N2) seasons. Age-adjusted hospitalization risks were 7-fold higher among individuals with versus without comorbidities (214 versus 30/100,000). The number-needed-to-vaccinate to prevent hospitalization was 82-fold lower for ≥75-years-olds with comorbidity (n = 1,995), who comprised 39% of all hospitalizations, than for healthy 18-64-year-olds (n = 163,488), who comprised just 6% of all hospitalizations.
Conclusions: In the context of broad-based influenza immunization programs (targeted or universal), severe outcome risks should be simultaneously examined by subtype, age, comorbidity, and vaccine status. Policymakers require such detail to prioritize promotional efforts and expenditures toward the greatest and most efficient program impact.
Keywords: burden; hospitalization; influenza; surveillance network.
. 2023 Oct 11:ciad627.
doi: 10.1093/cid/ciad627. Online ahead of print. Influenza hospitalization burden by subtype, age, comorbidity and vaccination status: 2012/13 to 2018/19 seasons, Quebec, Canada
Sara Carazo[SUP] 1 2 [/SUP], Charles-Antoine Guay[SUP] 1 2 3 4 [/SUP], Danuta M Skowronski[SUP] 5 [/SUP], Rachid Amini[SUP] 1 [/SUP], Hugues Charest[SUP] 6 7 [/SUP], Gaston De Serres[SUP] 1 2 8 [/SUP], Rodica Gilca[SUP] 1 2 8 [/SUP]
Affiliations
- PMID: 37819010
- DOI: 10.1093/cid/ciad627
Background: Influenza immunization programs aim to reduce the risk and burden of severe outcomes. To inform optimal program strategies, we monitored influenza hospitalizations over seven seasons, stratified by age, comorbidity and vaccination status.
Methods: We assembled data from four hospitals involved in an active surveillance network with systematic collection of nasal samples and PCR testing for influenza virus in all patients admitted through the emergency department with acute respiratory infection during 2012/13 to 2018/19 influenza seasons in Quebec, Canada. We estimated seasonal, population-based incidence of influenza-associated hospitalizations by subtype predominance, age, comorbidity and vaccine status, and derived the number-needed-to-vaccinate to prevent one hospitalization per stratum.
Results: The average seasonal incidence of influenza-associated hospitalization was 89/100,000 (95%CI: 86, 93), lower during A(H1N1) (49-82/100,000) than A(H3N2) seasons (73-143/100,000). Overall risk followed a J-shaped age pattern, highest among infants 0-5 months and adults ≥75 years. Hospitalization risks were highest for children <5 years during A(H1N1) but for adults ≥75 years during A(H3N2) seasons. Age-adjusted hospitalization risks were 7-fold higher among individuals with versus without comorbidities (214 versus 30/100,000). The number-needed-to-vaccinate to prevent hospitalization was 82-fold lower for ≥75-years-olds with comorbidity (n = 1,995), who comprised 39% of all hospitalizations, than for healthy 18-64-year-olds (n = 163,488), who comprised just 6% of all hospitalizations.
Conclusions: In the context of broad-based influenza immunization programs (targeted or universal), severe outcome risks should be simultaneously examined by subtype, age, comorbidity, and vaccine status. Policymakers require such detail to prioritize promotional efforts and expenditures toward the greatest and most efficient program impact.
Keywords: burden; hospitalization; influenza; surveillance network.