|
Title
|
|
|
|
Effect of the 2020/21 season influenza vaccine on SARS-CoV-2 infection in a cohort of Italian healthcare workers
| |
|
Author
|
|
|
|
| |
|
Abstract
|
|
|
|
| Objectives Healthcare workers (HCWs) are a priority group for seasonal influenza vaccination (SIV). The 2020/21 SIV campaign was conducted during the second wave of the COVID-19 pandemic. Vaccines, including SIV, may exert non-specific protective effects on other infectious diseases which may be ascribable to the concept of trained immunity. The aim of this study was to explore the association between 2020/21 SIV and SARS-CoV-2 positivity in a cohort of Italian HCWs. Methods In this observational study, a cohort of HCWs employed by a large (ca 5000 employees) referral tertiary acute-care university hospital was followed up retrospectively until the start of the COVID-19 vaccination campaign. The independent variable of interest was the 2020/21 SIV uptake. Both egg-based and cell culture-derived quadrivalent SIVs were available. The study outcome was the incidence of new SARS-CoV-2 infections, as determined by RT-PCR. Multivariable Cox regression was applied in order to discern the association of interest. Results The final cohort consisted of 2561 HCWs who underwent ≥1 RT-PCR test and accounted for a total of 94,445 person-days of observation. SIV uptake was 35.6%. During the study period, a total of 290 new SARS-CoV-2 infections occurred. The incidence of new SARS-CoV-2 was 1.62 (95% CI: 1.22–2.10) and 3.91 (95% CI: 3.43–4.45) per 1000 person-days in vaccinated and non-vaccinated HCWs, respectively, with an adjusted non-proportional hazard ratio of 0.37 (95% CI: 0.22–0.62). E-values suggested that unmeasured confounding was unlikely to explain the association. Conclusions A lower risk of SARS-CoV-2 infection was observed among SIV recipients. |
| |
|
Language
|
|
|
|
English
| |
|
Source (journal)
|
|
|
|
Vaccine / International Society for Vaccines. - Amsterdam
| |
|
Publication
|
|
|
|
Amsterdam
:
2022
| |
|
ISSN
|
|
|
|
0264-410X
| |
|
DOI
|
|
|
|
10.1016/J.VACCINE.2022.02.013
| |
|
Volume/pages
|
|
|
|
40
:12
(2022)
, p. 1755-1760
| |
|
Full text (Publisher's DOI)
|
|
|
|
| |
|