The emergence of Severe acute respiratory coronavirus 2 (SARS-CoV-2) and subsequent outbreak of COVID-19, is a global health challenge which has culminated in significant morbidity and mortality . The virus can be transmitted in humans by direct or indirect contact with respiratory droplets of an infected person . Although the viral RNA has been detected in stool, whole blood and urine of COVID-19 patients, transmission via these routes have not yet been documented [3, 4]. Infection with SARS-CoV-2 often presents with no symptom or a range of mild symptoms, including high temperature, dry cough, muscle pain, anosmia etc, and can progress into severe forms of the illness and possible death especially in the elderly and/or persons living with other comorbidities [5, 6]. Asymptomatic infections may be a substantial source of transmission and a challenge to infection control measures .
The first confirmed case of COVID-19 in sub-Saharan Africa was reported in Lagos, Nigeria on February 28, 2020, and as at 23rd November, 2020, a total of 743,298 RT-PCR tests had been performed in Nigeria, resulting in 66,383 onfirmed cases and 1,167 deaths (https://www.worldometers.info/coronavirus/#countries ) . Being a novel virus, sero-prevalence in a given population is presumed to be dynamic (negligible at onset and changing over the course of time). To date SARS-CoV-2 surveillance especially in Nigeria has focused primarily on individuals with high index of suspicion of COVID 19 even when it is apparent that there exist community transmissions. Although information on laboratory confirmed cases using RT PCR and deaths is important in monitoring the dynamics of the disease, they are less than ideal in estimating the proportion of infection in the entire population . Thus sero-prevalence studies are needed for an enhanced monitoring of the evolution of the outbreak and estimation of the actual infection fatality rate in the population
A quick search on SeroTracker ; a custom-built dashboard that systematically follows up on SARS-CoV-2 serological studies globally and displays findings on an interactive world map, shows paucity of data from sub-Saharan Africa. The SeroTracker enables easy comparison of estimates between regions and population groups clearly. Sero-surveillance of the populace allows inferences to be drawn on the extent of spread and cumulative incidence of infection in the population. Epidemiological studies focusing on the community will provide relevant data and expand our understanding of the spectrum of the disease.
Currently in Nigeria, given that SARS CoV-2 contact tracing relies solely on RT-PCR, the sero-prevalence of SARS-CoV-2-specific antibodies in different populations remains unclear. Consequently, the full spread of the disease, including the extent of mild or asymptomatic infections that do not require medical attention are not documented. Studies to determine the sero-prevalence SARS-CoV-2-specific antibodies in the community and specific population are paramount. These will provide means of measuring the extent of spread and appraise current control measures put in place by the authorities to curb the transmission of the virus. Additionally, knowledge provided by these studies will be found useful by policy makers in calibrating social interventions.
Although, there is frequently updated information on many aspects of the virus spread in Nigeria (e.g., numbers of patients tested positive for SARS-CoV-2, admitted and discharged from the hospital, mortalities) from the Nigeria Centre for Disease Control (NCDC), in contrast, there is very limited data on the percentage of the population with previous mild or asymptomatic infections. The proportion of the population with past and asymptomatic but active infection can fairly be estimated by testing for total antibody, IgG, IgA and IgM antibodies specific to SARS-CoV-2. These antibodies may confer immunity to repeat infection, although it remains unclear how long these immunities could last 
Healthy volunteers drawn from community blood donation units of major hospitals in Nigeria may provide vital sero-prevalence data on Covid-19 infection. Therefore, our study was aimed at sero-prevalence of SARS CoV-2 IgM and IgG in apparently healthy blood donors who had been recruited, screned and accepted to donate blood in the blood bank. This group of the population will provide a practical glimpse of the current situation of the virus spread at the community level.