Public transport workers and COVID-19 risk: a cohort study in Italy

IntroductionPublic transport workers have never stopped working during the COVID-19 pandemic. Despite the high personal contact with the public, studies in this job category on COVID-19 risk are scarce.Material and MethodsWe aimed to fill in this knowledge gap by investigating a cohort of over 2,000 employees of the Regional public transport sector in Sardinia, Italy. Incident COVID-19 cases were identified between 1 September 2020 – 6 May 2021 by real-time reverse transcription-polymerase chain reaction tests performed on nasopharyngeal swabs during periodic occupational health surveillance. We applied the age- and gender-specific COVID-19 incidence rates in the regional population at the same time frame to the correspondent strata of the study cohort to calculate the expected COVID-19 events. Age- and gender-adjusted relative risks (RRs) of COVID-19 and relative 95% confidence intervals (95% CIs) were estimated as the ratio between the observed and the expected events for the overall cohort and in two sub-cohorts: bus drivers and the rest of the workers (including administrative staff).ResultsMale bus drivers showed an increased COVID-19 risk (RR = 1.4, 95% C.I. 1.07 – 1.79). There was no excess risk among the rest of the personnel. Women were too few to allow reliable risk estimates.ConclusionsOur study suggests an excess risk of COVID-19 among bus drivers even in a relatively low incidence area, which could imply inadequacy of occupational preventive measures. Further larger studies, with detailed information on occupational and personal determinants, are warranted to disentangle the underlying causal factors and focus preventive strategies.

COVID-19 and non-Hodgkins lymphoma: a common susceptibility pattern? (preprint)

Objective To explore the link between COVID-19 incidence, socio-economic covariates, and NHL incidence. Design Ecological study design. Setting Sardinia, Italy. Participants We used official reports on the total cases of COVID-19 in 2020, published data on NHL incidence, and socio-economic indicators by administrative unit, covering the whole regional population. Main outcomes and measures We used multivariable regression analysis to explore the association between the natural logarithm (ln) of the 2020 cumulative incidence of COVID-19 and the ln-transformed NHL incidence in 1974-2003, weighing by population size and adjusting by socioeconomic deprivation and other covariates. Results The cumulative incidence of COVID-19 increased in relation to past incidence of NHL (p < 0.001), socioeconomic deprivation (p = 0.006), and proportion of elderly residents (p < 0.001) and decreased with urban residency (p = 0.001). Several sensitivity analyses confirmed the finding of an association between COVID-19 and NHL. Conclusion This ecological study found an ecological association between NHL and COVID-19. If further investigation would confirm our findings, shared susceptibility factors should be investigated among the plausible underlying mechanisms.

COVID-19 incidence in a cohort of public transport workers.

BACKGROUND: Previous research has shown an excess risk of COVID-19 among several occupations, but data on public transport workers are scarce. To investigate the occupational risk posed by contact with the public, we followed up the incidence of COVID-19 in a cohort of public transport workers. METHODS: We identified the incident cases of COVID-19 between 1 September 2020 - 6 May 2021 in a cohort of 2,052 employees of a public transport agency in Sardinia, Italy. The diagnosis of COVID-19 was based on a positive molecular test. To calculate the expected events, we applied the age- and gender-specific incidence rates of the regional population in the same time period to the correspondent strata of the study cohort. We estimated the relative risk (RR) of COVID-19 as the ratio between the observed and the expected events and its 95% confidence interval (95% C.I.) among the total cohort and in two sub-cohorts: bus drivers, and the rest of the personnel (administrative staff, train and metro drivers, workers in the mechanical shop, and in the railroad maintenance, and security). RESULTS: Bus drivers run an elevated risk of COVID-19 (RR = 1.4, 95% C.I. 1.07 - 1.79). There was no excess risk among the sub-cohort including the rest of the personnel. CONCLUSIONS: Our study suggests an excess risk of COVID-19 among bus drivers even in a relatively low incidence area, which could imply inadequacy of the preventive measures in place. Further, larger size studies with detailed information on personal and lifestyle characteristics are warranted.