The novel coronavirus disease 2019 (COVID- 19) has rapidly become a major public health crisis, affecting more than 278.6 million individuals, and causing over 5.4 million deaths globally as of December 2021.¹ The Nigeria Centre for Disease Control (NCDC) has reportedmore than 230,000 cases and 2,900 deaths in Nigeria as of 24 December 2021.² The disease also poses an important occupational health risk to healthcare workers (HCWs), as evidenced by high reporting of infection among this group.³

In the absence of curative drug for the disease, the use of nonpharmaceutical interventions (NPIs) including mask wearing and physical distancing have been adopted and have shown considerable effectiveness in reducing the impact of the pandemic.^4,5 Regardless, many cases have been reported among the general public as well as among HCWs.

In Nigeria, NCDC is responsible for infectious disease public health response activities through the national Emergency Operation Centre (EOC). During COVID-19 pandemic, the agency staff were involved in laboratory testing of COVID-19 samples, deployed for outbreak investigation amongst other activities. The first confirmed case among NCDC staff was detected on 9th April 2020 and was linked to exposure while deployed for investigation. Subsequently, more workers of the NCDC and partners have reported infection.

The regular surveillance of staff involved in outbreak response is very important as this can reduce the risk of healthcare associated infections and in turn, maintain the confidence of staff.⁶ Given the nature of work HCWs engage in, they are faced with a higher risk of infection with many diseases.⁷ It has been noted that to survey for emerging infectious diseases, it is crucial to monitor symptoms relating to specific infections among HCWs.^8,9 However, given that a higher percentage of people with COVID- 19 are asymptomatic, there is a risk for HCWs to import the virus, SARS-CoV-2 from contacts in the community to health facilities.¹⁰ With regards to this, study have shown HCWs becoming positive for SARSCoV-2 regardless of adherence to NPI measures within health facility.⁶

Staff from NCDC deployed for rapid response across the states in Nigeria are faced with different challenges including stress elements associated with insecurity, fatigue due to long working hours, as well as risk of exposure to infection and the attendant isolation or quarantine. Many studies have examine and documented the effect of SARS-CoV-2 on HCWs.^10,11 However, at NCDC no such study has been conducted previously among the agency staff. Here, we characterized transmission and psychosocial effect of SARS CoV-2 infection among NCDC staff as a learning curve on how best to mitigate these while minimising occupational transmission among frontline public health workers in future outbreaks.

NCDC is the national public health agency of Nigeria. It consists of 3 campuses (2 in Abuja and 1 in Lagos State) and over 300 staff across Nigeria out of which 172 were enrolled for this study

The study population eligible for participation in this study were NCDC staff infected with SARS-CoV-2 in all the agency campuses from November 2020 – December 2020, including veterinary and medical doctors, pharmacists, public health officers, medical laboratory scientists, administrative staff, and others. Staff who tested positive for COVID-19 were enrolled for this study.

We conducted a cross sectional study and enrolled all staff of the NCDC infected with SARS-CoV-2 from November to December 2020. In line with the principle of physical distancing and to prevent further spread of SARS-CoV-2, we deployed an online questionnaire for data collection. Survey monkey was used to develop the questionnaire, which was later delivered to the study participants via email.

The study characterised the transmission and psychosocial effect of the COVID-19 infection among 172 infected staff of the NCDC. The result suggest that majority of the participants were between the ages of 30 and 39, were males, worked at the laboratory department, confirmed deployment outside their primary duty stations during the pandemic, had contact with a confirmed case, and largely felt sad and stigmatized upon diagnosis with COVID- 19.

Staff of the NCDC are faced with occupational risk of COVID 19 as the agency is at the frontline of the response in Nigeria. A significant number of staff (i.e., 172) were infected with COVID-19 over the period of about 2 months following deployment to other states in Nigeria. It is possible that these staff failed to use the correct PPEs when attending to asymptomatic cases, thereby resulting in infection with COVID-19. Similar occupational risk has been reported by comparable centres. For instance, Wang et al (2020) reported 31 persons were infected with COVID-19 among staff of the Zhongnan Hospital of Wuhan University, China. Moreso, a study that evaluated COVID-19 infection among health workers in a primary health care facility in Ghana reported 14 out of 318 health workers were positive for COVID-19, and majority of these were asymptomatic.¹² In addition, a study conducted in 5 different hospitals in Ethiopia showed 39.6% seropositivity for COVID-19 among 1997 HCWs.¹³ Also, similar studies conducted among HCWs in Somalia and Egypt showed high rate of COVID-19 transmission.^14,15 Nonetheless, considering that this is a novel infection with transmission patterns and sources yet to be fully understood, it is expected that the risk of infection might be significantly high within such frontline centres.

Despite being aware of the risk of infection and the provision of personal protective equipment (PPE) and safety guidelines, poor adherence could account for the risk of COVID19 infection especially among the younger staff who form the majority of those infected (i.e., 30 to 39 years). A study conducted in Ghana have also reported reduced use of PPEs among HCWs when attending to asymptomatic COVID-19 cases.¹² In addition, the surge of demand for COVID-19 test increased workload among staff of the NCDC; and the resultant burnout and psychosocial fatigue may have contributed to staff not adhering properly to safety protocols, thereby exposing them to the SAR-CoV-2 infection.

Behavioural risk factor is a major element that increases the risk of COVID-19 infection. The higher risk of COVID-19 among male staff of the NCDC compared to females may be due to highrisk behaviour. As reported by Griffith et al, males are less probable to adhere to COVID-9 preventive measures such as the use of non-pharmaceutical interventions (e.g. wearing mask, washing hands and social distancing).¹⁶

The source of infection among the staff of the NCDC remained uncertain. Though majority attributed the source of infection to environmental transmission such as the use of ATM, the actual source is still unclear. Several studies have documented a wide range of sources such as contact with surfaces at the airport when travelling, person-to-person transmission through contact with symptomatic patients and asymptomatic carriers, and frequently touched surfaces in healthcare settings.^17-19 Also, as reported by a study conducted in Ethiopia poor perception of COVID-19 exposure as well as poor decontamination of sensitive areas are major risk factors correlating with positive cases among HCWs.²⁰

Nonetheless, laboratory personnel among the NCDC staff were the most affected. It is expected as the majority of those who travelled were laboratory personnel considering the need to set up more testing centres across the country to ease diagnosis of COVID-19 cases and for prompt isolation and management.

Due to the role played by public health laboratory personnel, direct contact with infected patients cannot be avoided since nasopharyngeal swaps must be collected to test suspected cases of COVID-19.²¹ The different manual touchpoints before the laboratory automated stage may pose risk of infection to staff involved in the process - especially, during processes like sample dilution and aliquoting. As a result, this category of workers are more prone to being infected by COVID-19 as compared to other staff and the result from this study confirms this trend. A similar higher risk among laboratory personnel was reported by Abdulkarim Hasan et al., (2020). According to this study, there is a 2-fold increased risk of SARS-CoV-2 infection among laboratory personnel.

Irrespective of the personnel infected with SAR-CoV-2, there were mixed experiences among those infected ranging from tearful, anger to being frightened. Existing community stigma as well as the novelty of the virus may be responsible for these diverse yet negative reactions. Within NCDC, working long hours without adequate rest during the pandemic in addition to becoming infected may have contributed to the negative psycho-social experiences. As reported by Cuiyan Wang et al (2020), psychological experience following a stigmatized infection ranges from anxiety to depression. Similar experiences have been reported by other front-line workers.²² For instance, a study in Algeria that assessed the psychosocial impact of COVID-19 reported high prevalence of anxiety and depression among HWCs.²³ In addition, a continentwide study that explored the impact of COVID-19 on HCWs in 13 African countries showed increased level of depression and fear during the pandemic.²⁴

This negative experiences highlight the need for safety nets such as psycho-social and financial support for frontline health workers or response team, especially those who become infected in the line of duty.²⁵ The NCDC introduced strategic psychosocial and financial support aimed at reducing the negative psychological experiences among its staff which was well received and reported as satisfactory by majority of the infected staff. Unlike the support provided by NCDC, report from some African countries show a different opinion. For example, a study conducted at a central hospital in Zimbabwe which explored the challenges faced by HCWs after confirmation with COVID-19 showed deficient psychosocial support and economic challenges related to HCWs bearing cost for diagnosis and treatment, experience of discrimination and stigma at the health facility and in the community in addition to lack of institutional support such as inadequate PPEs and COVID-19 testing. ²⁶

Compared with the number of people infected by SARS-COV epidemic in 2003, the total number of infections by COVID-19 is higher with daily increase and case fatality rate and unlike natural disasters such as hurricanes which require short-term emergency response, COVID-19 outbreak has a long-term implication.²⁵ This means front line health workers will have to deal with psychological and even social stress on a long-term basis.²⁵ Hence, additional planning is needed for managing such effect among front line staff. It is hoped that the financial support would be established to be sustainable as the risk of infection among frontline public health staff exists beyond pandemics.

Despite the provision of psycho-social and financial support, certain gaps in the management of infected staff were reported. Some of these gaps such as delay in accessing immediate pick-up services to the treatment/isolation centres as well as absence of prompt services at the treatment/isolation centres, added to the negative experiences. The advent of home-based treatment where appropriate, may address these gaps.

Every outbreak has peculiar elements, hence there is need for specialised preparedness training.²⁸ Due to the unexpected outbreak of COVID-19 with little known about the infection, and the short time available to get ready and equip staff, the preparedness training for emergency response may have been impaired and inadequate resulting in increased infection rates among deployed staff. Hence, the need for more robust preparedness training and capacity development focused on standard IPC measures.

There is significant occupational risk of COVID-19 infection especially among staff whose centres are at the front line. Psychosocial experiences among infected staff at these centres such as the NCDC is critical in driving policies aimed at reducing this occupational risk and the negative psycho-social experiences while improving services at the COVID-19 isolation/ treatment centres and strengthening capacity for future outbreaks.