Incidence of medically attended influenza and influenza virus infections confirmed by serology in Ningbo City from 2017-2018 to 2019-2020.
Influenza Other Respir Viruses
; 16(3): 552-561, 2022 05.
Article
in En
| MEDLINE
| ID: mdl-34989139
ABSTRACT
OBJECTIVES:
In mainland China, the disease burden of influenza is not yet fully understood. Based on population-based data, we aimed to estimate incidence rates of medically attended influenza and influenza virus infections in Ningbo City.METHODS:
We used data for outpatient acute respiratory illness (OARI) from a platform covering all health and medical institutes in Yingzhou District, Ningbo City. We applied generalized additive regression models to estimate influenza-associated excess incidence rate of OARI by age. We recruited local residents aged ≥60 years in the autumn of 2019 and conducted follow-up nearly 9 months later. Every survey, the sera were collected for testing hemagglutination inhibition antibody.RESULTS:
From 2017-2018 to 2019-2020, the annual average of influenza-associated incidence rate of OARI in all ages was 10.9%. The influenza-associated incidence rate of OARI was the highest in 2017-2018 (16.9%) and the lowest in 2019-2020 (4.8%). Regularly, influenza-associated incidence rates of OARI were the highest in children aged 5-14 years (range 44.1-77.6%) and 0-4 years (range 8.3-46.6%). The annual average of excess OARI incidence rate in all ages was the highest for influenza B/Yamagata (3.9%). The overall incidence rate of influenza infections indicated by serology in elderly people was 21% during the winter season of 2019-2020.CONCLUSIONS:
We identified substantial outpatient influenza burden in all ages in Ningbo. Our cohort study limited in elderly people found that this age group had a high risk of seasonal influenza infections. Our study informs the importance of increasing influenza vaccine coverage in high-risk population including elderly people.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
Influenza, Human
Type of study:
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Adolescent
/
Aged
/
Child
/
Child, preschool
/
Humans
/
Infant
/
Middle aged
Language:
En
Journal:
Influenza Other Respir Viruses
Journal subject:
VIROLOGIA
Year:
2022
Document type:
Article