- •47.5% of HCWs 47.5% had a history of COVID-19 symptoms.
- •5.1% of HCW were seropositive.
- •Neither gender, sex, BMI, nor having children were associated with seropositive status.
- •Working in a COVID-19 unit was associated with positive RT-PCR test.
- •Smoking was associated with a lower seroprevalence among HCWs.
Study design and participants
Description of the cohort
|N = 4696|
|Age in 2020 (years)|
|Mean ± SD [95%CI]||40.4 ± 11.4 [40.1; 40.7]|
|Median (Q1 - Q3)||40.0 (30.0–50.0)|
|Min - Max||18.0–71.0|
|Children (all ages)|
|Children under 2 years old|
|Children between 2 and < 5 years old|
|Children between 5 and < 10 years old|
|Children between 10 and < 15 years old|
|Children aged 15 years and older|
|Working in a COVID-19 unit|
|At least one positive RT-PCR test|
|COVID-19 clinical manifestations (all)|
|Loss of taste/smell|
Epidemiological and clinical factors associated with a history of positive RT-PCR test
Epidemiological and clinical factors associated with positive SARS-cov-2 serology
|N||Seropositivity||Bivariate regression||Multivariate regression|
|n||%||Odds ratio||95%CI||p||Odds ratio||95%CI|
|Age in 2020||0.497|
|Children (all ages)||0.456|
|Children under 2 years old||0.416|
|Children between 2 and < 5 years old||0.548|
|Children between 5 and < 10 years old||0.785|
|Children between 10 and < 15 years old||0.449|
|Children aged 15 years and older||0.697|
|Working in a COVID-19 unit||0.223|
|At least one positive RT-PCR test||<0.001||<0.001|
|COVID-19 clinical manifestations |
|Loss of taste/smell||<0.001||<0.001|
- Miyara M.
- Tubach F.
- Pourcher V.
- Morélot-Panzini C.
- Pernet J.
- Haroche J.
- et al.
|Reference||Study population||Population size||Results||Conclusion|
|Rentsch et al., 2020 [||Patients hospitalized and/or in intensive care units||3789||OR = 0.45, 95%CI [0.35–0.57]||Current smoking was associated with decreased likelihood of COVID-19|
|Guan et al., 2020 [|
|Patients hospitalized and/or in intensive care units||661||OR = 0.20, 95%CI [0.08–0.51]|
Adjustment for age: OR = 0.23, 95%CI [0.09–0.59]
Adjustment for occupation: OR = 0.27, 95%CI [0.10–0.71]
|Smoking was found to be associated with a lower risk of infection, and this association remained significant after adjustment for age or occupation|
|De Lusignan et al., 2020 [|
|Outpatients||3802||Adjusted OR = 0.49; 95%CI [0.34–0.71]||Active smoking was associated with decreased odds of positive test result|
|Miyara et al., 2022 [||Outpatients||479||OR = 0.24, 95% CI [0.12–0.48]||The rate of active daily smoking was significantly lower in COVID-19 patients than in the general 2019 French population after standardization by age and gender|
|Hospitalized patients||479||OR = 0.24, 95%CI [0.14–0.40]|
|Jackson et al., 2021 [|
|Outpatients||53,002||Adjusted OR = 1.79, 95%CI [1.22–2.62]||Current smoking was independently associated with self-reported confirmed COVID-19 infection|
|Mostafa et al., 2021 [|
|Healthcare workers||4040||Former smokers: adjusted OR = 0.45, 95%CI [0.11–1.89] (p = 0.273)|
Current smokers: adjusted OR = 0.65, 95%CI [0.38–1.09] (p = 0.101)
|Former or recent smoking was not associated with positive SARS-CoV-2 test results in HCWs|
Conflict of interest
Appendix A. Supplementary data
- Multimedia component 1
- An international survey of healthcare workers use of personal protective equipment during the early stages of the COVID-19 pandemic.J Am Coll Emerg Physicians Open. 2021; 2e12392
- Prevalence of SARS-Cov-2 antibodies and living conditions: the French national random population-based EPICOV cohort.BMC Infect Dis. déc 2022; 22: 41
- Risk of COVID-19 in health-care workers in Denmark: an observational cohort study.Lancet Infect Dis. déc 2020; 20: 1401-1408
- Effectiveness of preventive measures in keeping low prevalence of SARS-CoV-2 infection in health care workers in a referral children's hospital in southern Italy.Pediatr Rep. 4 mars 2021; 13: 118-124
- Seroprevalence of SARS-CoV-2, symptom profiles and sero-neutralization in a suburban area.France. Viruses. 4 juin 2021; 13: 1076
- Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) seroconversion and occupational exposure of employees at a Swiss university hospital: a large longitudinal cohort study.Infect Control Hosp Epidemiol. 19 mars 2021; : 1-8
Hartard C, Agrinier N, Franck P, Prin-Mathieu C, Debourgogne A, Venard V, et al. Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) seroprevalence among laboratory staff: safe handling of coronavirus disease 2019 (COVID-19) samples. Infect Control Hosp Epidemiol. :1-2.
- Clinical characteristics of coronavirus disease 2019 in China.N Engl J Med. 30 avr 2020; 382: 1708-1720
- Lower rate of daily smokers with symptomatic COVID-19: a monocentric self-report of smoking habit study.Front Med. 2022 Jan 5; 8 (PMID: 35071251; PMCID: PMC8766759): 668995https://doi.org/10.3389/fmed.2021.668995
- Occupational exposure in the lombardy region (Italy) to SARS-CoV-2 infection: results from the MUSTANG–OCCUPATION–COVID-19 study.IJERPH. 4 mars 2021; 18: 2567
- SARS-Co-V2 infection in never, former, and current tobacco/nicotine users: a cohort study of 4040 Egyptian healthcare workers.BMC Public Health. déc. 2021; 21: 1243
- COVID-19, smoking and inequalities: a study of 53 002 adults in the UK.Tobac Control. déc 2021; 30 (e111-21)
- Does smoking have an impact on the immunological response to COVID-19 vaccines? Evidence from the VASCO study and need for further studies.Publ Health Forum. 2022; 203: 97-99
- The Aryl hydrocarbon receptor mediates tobacco-induced PD-L1 expression and is associated with response to immunotherapy.Nat Commun. 8 mars 2019; 10: 1125
- Electronic cigarette aerosol is cytotoxic and increases ACE2 expression on human airway epithelial cells: implications for SARS-CoV-2 (COVID-19).JCM. 3 mars 2021; 10: 1028
- Cigarette smoking and infection.Arch Intern Med. 8 nov 2004; 164: 2206-2216
- Covid-19 testing, hospital admission, and intensive care among 2,026,227 United States veterans aged 54-75 years.medRxiv. 2020 Apr 14; https://doi.org/10.1101/2020.04.09.20059964
- Risk factors for SARS-CoV-2 among patients in the oxford royal college of general practitioners research and surveillance centre primary care network: a cross-sectional study.Lancet Infect Dis. 1 sept 2020; 20: 1034-1042