Clinical characteristics of bus drivers and field officers infected with COVID-19: A cross-sectional study from Istanbul

1Introduction

In metropolitans, buses are private indoor environments and are often very busy during rush hour. If poorly ventilated, they are ideal environments for the airborne spread of infectious diseases, especially drivers at greatest risk due to the long exposure time to this environment [1]. According to Istanbul Electric Tramway and Tunnel (IETT) transportation statistics for 2020, a passenger spends an average of 24 minutes in a vehicle during a journey. However, in London, this contact time is 15 minutes on average, and a contact time of 15 minutes or less is not considered risky. A driver working in Istanbul, on the other hand, works on a route of 2–3 hours on average, this time may be longer depending on Istanbul traffic. For this reason, the driver makes two rings of the same route, and the total exposure time can reach 6–7 hours [2, 3]. Especially considering that drivers are subject to the longest exposure time, these factors also play an important role in public transport-borne contagion in a big metropolis like Istanbul. There are two possible routes of transmission of coronaviruses on a bus, by air and by surfaces. Most buses in Istanbul have a three-door system with one entrance and two exits. The necessity for passengers to pass by the driver while getting on the bus creates an important moment of contact [4].

For bus driver deaths in England and Wales, between March and May 2020, the Office for National Statistics (ONS) estimates the overall occupational death rate for bus drivers from 128 per 100,000 for all-cause and deaths involving COVID-19, which is greater than other occupations (78 per 100,000). This is almost twice what would be expected from bus and coach driver fatalities in the previous five years. England and Wales had 70 more bus and bus driver deaths than expected, 53 of whom had COVID-19 written on their death certificate [5]. According to the COVID-19 data of the General Directorate of IETT enterprises in Istanbul, five bus drivers were died in 2020 [3]. As stated in Kamga and Eickeyer’s study, social distancing measures introduced to prevent the spread of COVID-19 are very important to protect not only passengers but also drivers and other employees working in this field, such as field operations officers and ticket attendants [6].

This situation forced the bus drivers and the officers working in the field with them to a high chain of contact during the intense periods of the pandemic. The effects of the working conditions of this occupational group, which has been in contact with passengers for a long period of travel and have continued to work with minimal interruptions even in an extraordinary situation such as a pandemic, on their cases of clinical characteristics on COVID-19 should be evaluated. Therefore, the aim of this study is to evaluate the clinical status of bus drivers and officers working with them in public transportation in Istanbul, a metropolitan city, and who had COVID-19. Although there are studies in the literature including on drivers who have had COVID-19, no study has been encountered that deals with the disease according to the state of hospitalization. For this reason, this study also aimed to compare the situations of those who are treated at home or in the hospital.

2Methods

3Results

This study was conducted with 477 individuals who were all males, and most of whom were bus drivers (79.04%). The mean age, weight and height were found 43.39±6.66 years, 88.85±15.17 kg, and 175±6.47 cm, respectively. Also, the mean BMI of participants was found 29.96±4.36 kg/m². The majority of individuals are between the ages of 40–49 (57.02%) and had normal BMI (49.48%), but a high obesity rate is also recorded (34.59%). In all individuals, 29.35% are regular smokers and 89.67% of those with chronic diseases have diabetes (Table 1).

Most of these individuals (75%) were not hospitalized, and the majority (70.44%) had moderate or mild symptoms (Table 2). The rate of those showing more than one symptom is 86.16%. The most common symptoms are muscle and joint pain (77.57%), fever (58.07%) and anosmia (55.97%). When the treatments received by these individuals were examined, it was determined that 36.48% received antivirals, 36.68% were administered antibiotics and 24.53% underwent oxygen therapy.

As shown in Table 3, significant differences were found between age, BMI, smoking and use of nutritional supplements values between those who were not hospitalized and those who were hospitalized (p < 0.05). No statistically significant difference was found between any chronic disease status (p > 0.05). There was a significant difference between the groups in terms of nutritional supplements (p = 0.045), but not with the type of product. Individuals in both groups use vitamin C supplements the most (28.21% in Hospitalized, 38.89% in Home). While vitamin D is preferred in the second, the preference of other nutritional supplement types is low.

Significant differences were found between pre-disease glucose and vitamin B₁₂ values between hospitalized and home (p < 0.05). There was no significant difference in the other biochemical parameters (p > 0.05) (Table 4).

4Discussion

In this study, the clinical characteristics and results of 477 COVID-19 survivors working as bus drivers and field officers were examined. It was determined that those who survived the disease at home were younger and had a lower BMI. It was also observed that those who survived in the hospital lost more weight.

Advanced age and chronic diseases such as cardiovascular disease, hypertension, diabetes mellitus, chronic lung disease, chronic renal failure, and obesity are considered risk factors for any serious conditions. When the distribution of patients who died in Italy and China are examined, it is seen that the mortality rate is less than 1% for those under the age of 60, 3.5% for those over the age of 60 and up to 20% for those over the age of 80. Mortality rates are also higher in males [8, 9]. In the data coming from Italy, which is the first country to be affected by the pandemic after China, the death rate in the elderly population is 20.2%, a significantly higher mortality rate (0.4–3.5%) than that of the younger population [10]. In our study, it was observed that the age of individuals who are in Hospitalized group was higher than that of those who received home treatment. This situation shows a parallel with other tables that have emerged. Advanced age is also an important risk factor for COVID-19 treatment in drivers and field officers. Especially for drivers who are in direct contact with passengers, health status should be monitored and additional measurements should be planned.

The most common symptoms of COVID-19 are fever, cough, shortness of breath and fatigue. Some patients may have myalgia, nasal congestion, sore throat, headache, arthralgia, and diarrhea. In a study by Fu et al. [11] conducted on 3600 patients, fever was observed in 83% of the patients, cough in 60%, fatigue in 38%, myalgia in 28%, shortness of breath in 24.9%, headache in 14%, diarrhea in 8%. 5.6% of patients were asymptomatic. On the other hand, in the study of Tian et al. [12] in which 262 patients were evaluated, fever was seen in 82.1%, cough in 45.8%, fatigue in 26.3%, dyspnea in 6.9%, and headache in 6.5%.5% of patients were asymptomatic. In our study, the most common symptom was found to be muscle-joint pain (77.57%), fever in 58.07%, inability to smell in 55.97%, cough in 52.62%, sore throat in 48.64%, weakness in 6.08%, and headache in 15.51%. In four of the first 43 cases that emerged in Thailand at the beginning of the epidemic, transmission from tour buses was determined, and these cases presented with fever and pneumonia. In this observational study, the researchers speculated that tourist bus drivers may be responsible for transmitting the virus to their co-workers or local habitats, possibly during coffee breaks [13]. The relationship of contamination and increased risk can be predicted for our cases as well.

The clinical condition in COVID-19 may vary according to the underlying diseases. Huang et al. [14] reported that 32% of 41 patients had an underlying disease; diabetes mellitus was observed in 20%, hypertension in 15% and cardiovascular disease in 15% of these patients. In another study, Lai et al. [15] reported that the most common underlying diseases in adult patients were cardiovascular disease, diabetes mellitus and hypertension. In our study, hypertension and diabetes mellitus were the most common underlying conditions. The probability of comorbidity was higher in hospitalized patients. More comprehensive data on the severity and duration of each comorbidity with detailed information are needed to examine the relationship between COVID-19 and underlying chronic diseases.

Another remarkable clinical condition is weight loss in the hospitalized group (–7.49±4.65, p = 0.013). Holdoway [16] also drew attention to unwanted weight loss in recommendations for the management of diets during or after the illness of COVID-19 survivors. Accordingly, individuals should be screened in terms of malnutrition and the reason for weight loss should be tried to be understood. While hospital malnutrition may be a possibility, it should not be overlooked that COVID-19 may cause loss of taste and smell or psychological factors such as anxiety may reduce food intake.

The relationship between hospitalization and obesity, as a comorbidity, for COVID-19 has been investigated previously, but no direct relationship has been found in general, obesity may predispose young patients with COVID-19 to more serious illnesses that require hospitalization and intensive care unit admission. It has been shown that obese individuals are more likely to need mechanical ventilation in the event of contracting COVID-19 and have higher mortality rates. Therefore, it should not be forgotten that obesity may be closely related to the risk of contracting COVID-19 [17]. Lighter et al. [18] found that COVID-19 patients who younger than 60 years of age are more likely to be received to the hospital or intensive care unit when they are obese. Simonnet et al. [19] and Caussy et al. [20] found a high proportion of COVID-19 patients requiring mechanical ventilation with an increased BMI. In our study, 89.67% of the patients also had a high rate of obesity. The BMI of those who survived the disease in the hospital is 30.05 kg/m² and there is a significant relationship between BMI and the state of recovering from the disease at home or in the hospital. Here, it is necessary to consider that risk factors relevance with COVID-19 are also under the influence of factors such as genetics, nutritional status, immunological predisposition.

In this study, the smoking rate of Home was 32.5% which is 22.2% higher than Hospitalized. Low prevalence of smoking in hospitalized COVID-19 patients has been previously reported by other researchers from China, and Spain. In these studies, there is the opinion that nicotine can provide protection against coronavirus infection due to its immunomodulatory effects. Nevertheless, more detailed epidemiological studies are needed to examine the relationship of smoking with the course of COVID-19 [21, 22].

According to a study supported by the PLife COVID-19 Online Studies, the curiosity in immune-related supplements and foods like vitamins C and D, zinc, omega-3, garlic, ginger, together with their consumption increased during the COVID-19 outbreak in March 2020. The main reason to increase nutritional support is to improve immune strength and health [23, 24]. In our study, 56.6% of the participants used nutritional supplements. It was determined that 58.1% of those who used supplements recovered from the disease at home. The most preferred supplement in our study was vitamin C, but no statistically significant effect was shown between the types of nutritional supplements and the severity of the disease. This may be due to various reasons such as duration of use, dose, and continuity.

There are some limitations of the study. Although the usage of masks is mandatory at the time of the study, it is not known exactly how well individuals comply with personal protective equipment and precautions. In addition, purposive sampling is also a limitation. One of the other limitations is the inability to access the medical records of some patients due to the work-from-home system during the pandemic period, and some data are missing. In order to reduce the impact of this limitation, individuals with incomplete medical information were excluded from the study.

5Conclusion

COVID-19 affects bus drivers and field operations officers working in close contact with each other, with hitherto known effects. Especially, advanced age and high BMI are important risk factors affecting treatment at home or in the hospital in the cases in this study. It should not be forgotten that these people, who are exposed to crowded groups for a long time due to their occupational status, are not only potential patients but also potential carriers and are contagious. For this reason, taking special precautions for this occupational group will also be protective for public health in general. It is recommended to isolate the driver’s seat of buses with a cabin, to provide personal protective equipment free of charge and uninterruptedly by employers, to control the use of equipment by admins, to provide regular trainings to these individuals on the importance of equipment and hygiene rules for both personal and public health. At the same time, it is thought that regular weight loss and weight monitoring of individuals with high BMI under the control of a dietitian will have positive reflections on the course of both COVID-19 and other diseases and general health burden.

Author contributions

Conceptualization and methodology: H.H.G., M.K.S.; Data collection: M.K.S.; Data analysis and interpretation: H.H.G., M.K.S., S.E.; Drafting the article: H.H.G., M.K.S.; Revising and final approval of the manuscript: H.H.G., M.K.S., S.E.