Influenza vaccine effectiveness in preventing hospital encounters for laboratory-confirmed infection among Italian adults, 2022/23 season.
Vaccine
; 41(33): 4861-4866, 2023 07 25.
Article
in En
| MEDLINE
| ID: mdl-37385889
ABSTRACT
The effectiveness of seasonal influenza vaccination (SIV) varies from year to year. Interim estimates of vaccine effectiveness (VE) in outpatient settings have suggested that the 2022/23 northern hemisphere SIV was 54â¯% effective. The main goal of this study was to measure the 2022/23 SIV VE among Italian adults in a hospital setting. The study adopted a retrospective test-negative case-control design and was conducted in a large tertiary hospital (Genoa, Italy) between October 2022 and April 2023. Adult (≥18 years) patients accessing the hospital's Emergency Department for symptoms ascribable to an acute respiratory infection, for which a reverse-transcription real-time polymerase chain reaction test for the detection of influenza virus was prescribed, were potentially eligible. Of 33,692 referrals assessed, 487 patients were included in the study. A total of 13â¯% of patients were positive for influenza, most of which (63â¯%) belonged to the A(H3N2) subtype. SIV VE was 57â¯% (95â¯% CI 11-81â¯%), 53â¯% (95â¯% CI 2-80â¯%) and 38â¯% (95â¯% CI -34-74â¯%) against any influenza, influenza A and A(H3N2), respectively. Although no cases caused by A(H1N1)pdm09 and B strains were observed among vaccinated individuals, VE estimates against the latter were imprecise, owing to their low detection rates. In conclusion, the 2022/23 SIV was moderately effective against hospital encounters for laboratory-confirmed influenza.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
Influenza, Human
/
Influenza A Virus, H1N1 Subtype
Type of study:
Observational_studies
/
Risk_factors_studies
Limits:
Adult
/
Humans
Country/Region as subject:
Europa
Language:
En
Journal:
Vaccine
Year:
2023
Document type:
Article