tetano
Editor, Senior Moderator
Clin Infect Dis
. 2024 Oct 24:ciae491.
doi: 10.1093/cid/ciae491. Online ahead of print. Influenza Vaccine Effectiveness Against Illness and Asymptomatic Infection in 2022-2023: A Prospective Cohort Study
Elizabeth B White[SUP] 1 2 [/SUP], Lauren Grant[SUP] 1 [/SUP], Josephine Mak[SUP] 3 [/SUP], Lauren Olsho[SUP] 4 [/SUP], Laura J Edwards[SUP] 4 [/SUP], Allison Naleway[SUP] 5 [/SUP], Jefferey L Burgess[SUP] 6 [/SUP], Katherine D Ellingson[SUP] 6 [/SUP], Harmony Tyner[SUP] 7 [/SUP], Manjusha Gaglani[SUP] 8 [/SUP], Karen Lutrick[SUP] 9 [/SUP], Alberto Caban-Martinez[SUP] 10 [/SUP], Gabriella Newes-Adeyi[SUP] 4 [/SUP], Jazmin Duque[SUP] 4 [/SUP], Sarang K Yoon[SUP] 11 [/SUP], Andrew L Phillips[SUP] 11 [/SUP], Mark Thompson[SUP] 12 [/SUP], Amadea Britton[SUP] 3 [/SUP], Brendan Flannery[SUP] 1 [/SUP], Ashley Fowlkes[SUP] 1 [/SUP]
Affiliations
Background: Previous estimates of vaccine effectiveness (VE) against asymptomatic influenza virus infection based on seroconversion have varied widely and may be biased. We estimated 2022-2023 influenza VE against illness and asymptomatic infection in a prospective cohort.
Methods: In the HEROES-RECOVER cohort, adults at increased occupational risk of influenza exposure across 7 US sites provided weekly symptom reports and nasal swabs for reverse transcription-polymerase chain reaction (RT-PCR) influenza testing. Laboratory-confirmed influenza virus infections were classified as symptomatic (≥1 symptom) or asymptomatic during the week of testing. Participants reported demographic information and vaccination through surveys; most sites verified vaccination through medical record and immunization registry review. Person-time was calculated as days from the site-specific influenza season start (September-October 2022) through date of infection, study withdrawal, or season end (May 2023). We compared influenza incidence among vaccinated versus unvaccinated participants overall, by symptom status, and by influenza A subtype, using Cox proportional hazards regression adjusted for site and occupation. We estimated VE as (1 - adjusted hazard ratio) × 100%.
Results: In total, 269 of 3785 (7.1%) participants had laboratory-confirmed influenza, including 263 (98%) influenza A virus infections and 201 (75%) symptomatic illnesses. Incidence of laboratory-confirmed influenza illness among vaccinated versus unvaccinated participants was 23.7 and 33.2 episodes per 100 000 person-days, respectively (VE: 38%; 95% CI: 15%-55%). Incidence of asymptomatic influenza virus infection was 8.0 versus 11.6 per 100 000 (VE: 13%; 95% CI: -47%, 49%).
Conclusions: Vaccination reduced incidence of symptomatic but not asymptomatic influenza virus infection, suggesting that influenza vaccination attenuates progression from infection to illness.
Keywords: asymptomatic infection; cohort; influenza; symptomatic illness; vaccines.
. 2024 Oct 24:ciae491.
doi: 10.1093/cid/ciae491. Online ahead of print. Influenza Vaccine Effectiveness Against Illness and Asymptomatic Infection in 2022-2023: A Prospective Cohort Study
Elizabeth B White[SUP] 1 2 [/SUP], Lauren Grant[SUP] 1 [/SUP], Josephine Mak[SUP] 3 [/SUP], Lauren Olsho[SUP] 4 [/SUP], Laura J Edwards[SUP] 4 [/SUP], Allison Naleway[SUP] 5 [/SUP], Jefferey L Burgess[SUP] 6 [/SUP], Katherine D Ellingson[SUP] 6 [/SUP], Harmony Tyner[SUP] 7 [/SUP], Manjusha Gaglani[SUP] 8 [/SUP], Karen Lutrick[SUP] 9 [/SUP], Alberto Caban-Martinez[SUP] 10 [/SUP], Gabriella Newes-Adeyi[SUP] 4 [/SUP], Jazmin Duque[SUP] 4 [/SUP], Sarang K Yoon[SUP] 11 [/SUP], Andrew L Phillips[SUP] 11 [/SUP], Mark Thompson[SUP] 12 [/SUP], Amadea Britton[SUP] 3 [/SUP], Brendan Flannery[SUP] 1 [/SUP], Ashley Fowlkes[SUP] 1 [/SUP]
Affiliations
- PMID: 39446477
- DOI: 10.1093/cid/ciae491
Background: Previous estimates of vaccine effectiveness (VE) against asymptomatic influenza virus infection based on seroconversion have varied widely and may be biased. We estimated 2022-2023 influenza VE against illness and asymptomatic infection in a prospective cohort.
Methods: In the HEROES-RECOVER cohort, adults at increased occupational risk of influenza exposure across 7 US sites provided weekly symptom reports and nasal swabs for reverse transcription-polymerase chain reaction (RT-PCR) influenza testing. Laboratory-confirmed influenza virus infections were classified as symptomatic (≥1 symptom) or asymptomatic during the week of testing. Participants reported demographic information and vaccination through surveys; most sites verified vaccination through medical record and immunization registry review. Person-time was calculated as days from the site-specific influenza season start (September-October 2022) through date of infection, study withdrawal, or season end (May 2023). We compared influenza incidence among vaccinated versus unvaccinated participants overall, by symptom status, and by influenza A subtype, using Cox proportional hazards regression adjusted for site and occupation. We estimated VE as (1 - adjusted hazard ratio) × 100%.
Results: In total, 269 of 3785 (7.1%) participants had laboratory-confirmed influenza, including 263 (98%) influenza A virus infections and 201 (75%) symptomatic illnesses. Incidence of laboratory-confirmed influenza illness among vaccinated versus unvaccinated participants was 23.7 and 33.2 episodes per 100 000 person-days, respectively (VE: 38%; 95% CI: 15%-55%). Incidence of asymptomatic influenza virus infection was 8.0 versus 11.6 per 100 000 (VE: 13%; 95% CI: -47%, 49%).
Conclusions: Vaccination reduced incidence of symptomatic but not asymptomatic influenza virus infection, suggesting that influenza vaccination attenuates progression from infection to illness.
Keywords: asymptomatic infection; cohort; influenza; symptomatic illness; vaccines.