## 4 Discussion  
There are over 1 billion agricultural workers in the world [15]. Italy is first in Europe for the number of people employed in this sector, with 1.125 million workers, followed by Spain and France [16; 17; 18].  
The agri-food production sector, during the first pandemic phase, was one of the few that remained active. In fact, it even increased production activity [6].  
Workers employed in the harvesting activity or in the production chain rapidly found themselves wanting to adopt all the necessary measures to face the COVID-19 emergency [19].  
Analysis of the two groups revealed statistically significant differences in the health and safety risks to which workers were exposed.  
In particular, agricultural workers were significantly exposed to climatic, UV and chemical hazards, unlike workers in the supply chain. The latter, in fact, as mentioned above, carried out most of the time indoor activities and therefore were not directly exposed to UV rays nor to excessive temperature changes. Moreover, they did not deal with the administration of agro pharmaceuticals, therefore chemical hazards were absent.  
Finally, the COVID-19 risk significantly differed between the two groups, low in agricultural workers and medium in supply chain workers. This was also indicated by OSHA, 2020 and INAIL, 2020 because indoor workers, due to their work, could not respect the interpersonal distance sufficient to ensure lower contagion risks.  
In our study, workers were subjected to a protocol created by a reworking of national legislation and the most recent guidelines.  
The results showed us that an effective filter was created on entry into the company to detect the subjects with symptoms suggestive of COVID-19. In fact, 15% of workers entered the protocol and among these one was found positive for SARS-CoV-2 following the molecular swab performed by the department of prevention.  
The main symptoms found in the two groups were: fever, muscle or joint pain, dry cough, nausea or vomiting, loss of taste and smell and values of oxygen saturation <95%. Excluding the fever, the other symptoms were very nonspecific. In fact, already in the first studies coming from China, the temperature rise was not always present in positive subjects [20]. The protocol adopted, allowed us to identify at an early stage 49 workers who could have escaped only by measuring the temperature.  
The seroprevalence study showed that no worker developed anti-SARS-CoV-2 antibodies other than the worker who contracted the virus. This may be attributable to the fact that the SARS-CoV-2 positive worker was identified at an early stage of symptomatology when he was not yet contagious. In fact, many studies showed that asymptomatic and pauci-symptomatic subjects spread the virus less than the symptomatic subjects [21; 22].  
The limitations of the protocol are related to the fact that during the first pandemic phase, Sicily experienced a low number of infections compared to other regions of northern Italy.  
However, the introduction of a protocol that allowed the company to work safely allowed the identification of the positive case to SARS-CoV-2 at an early stage.  
\begin{table}
\begin{tabular}{l c c c c c c} \hline  & **IgG\(-\)** & **IgG+** & **IgM\(-\)** & **IgM+** & **NMS** & \(p\)**-Values** \\ \hline Agricultural workers & 180 (55\%) & 0 & 180 (55\%) & 0 & 0 & n.s. \\ \hline Supply chain workers & 147 (44\%) & 1(1\%) & 148 (45\%) & 0 & 1 (1\%) & n.s. \\ \hline \end{tabular} n.s. not significant; NMS: nasopharyngeal Molecular Swab Positive.  
\end{table}
Table 4: Immune status between the two groups of workers toward SARS-CoV-2.  
Outcome Measures on Cost-Utility and Budget Impact  
The cost and budget impact of the intervention were low. In particular, the total cost of the kits and medical performance was around EUR 25,000. Considering the company's 2020 turnover (over EUR 50 million), the impact on the company balance sheet considering the risk/benefit ratio has been deposited towards the implementation of the protocol.