…for Gombe State, it was 1 in 10 persons.
“Survey findings released Thursday revealed that the prevalence of SARS-CoV-2 antibodies was 23% in Lagos and Enugu States, 19% in Nasarawa State, and 9% in Gombe State,” NCDC and NIMR said in a statement.
“This means that as many as 1 in 5 individuals in Lagos, Enugu and Nasarawa State would have ever been infected with SARS-CoV-2. In Gombe, the proportion is about 1 in 10.”
Lagos State is the epicenter of the virus in Nigeria and has the highest burden of the virus in the country – official statistics show that the state has recorded 55, 122 confirmed cases and 403 deaths from the virus as of February 24.
But the NCDC and NIMR survey suggests that the official record is grossly understated. With state authorities putting the population of the state at least 24.6 million, about 4, 920, 000 million might have contracted the virus.
Statistics by Johns Hopkin University Coronavirus Centre showed that at least 112.5 million people have been infected with 2.49 million deaths recorded worldwide as of 10:30 am (Nigerian time) on Thursday.
It was gathered that between September and October 2020, the surveys were designed to improve the estimate of the burden of COVID-19 infection in the country and provide a more detailed estimate of the extent of infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus – the virus that causes COVID-19.
Blood samples were collected from over 10,000 individuals residing in a representative sample of households in the four states. The blood samples were then tested for the presence of SARS-CoV-2 antibodies applying locally validated laboratory tests.
Individuals who provided blood samples also answered a brief questionnaire that enabled the study team to characterise factors related to positivity and identify which population groups were most affected.
These rates of infection are higher than those reported through the national surveillance system and reveal that the spread of infection in the states surveyed is wider than is obvious from surveillance activities. This is not surprising for COVID-19, given that a majority of those infected do not have any symptoms.
Results of the survey further showed higher rates of infection among: 1) males than females (for example, 10% vs. 7% in Gombe and 21% vs. 17% in Nasarawa); 2) urban compared to rural and residents (for example, 28% vs. 18% in Enugu and 23% vs. 19% in Lagos); and persons aged 18-64 years.
There were also variations across the local government areas (LGA) within the four states. The survey team noted that these observations are in tandem with what had been reported by the NCDC based on the national surveillance system.
In interpreting the results, the survey team noted that “SARS-CoV-2 emerged only one year ago and antibody response according to severity of infection and the duration of antibody persistence are not yet completely understood”.
Given the high proportion of asymptomatic cases in Nigeria, the true seroprevalence of ever having infection may be underestimated in the survey if individuals infected early in the outbreak no longer had sufficient antibodies for detection when the survey was conducted.
The results from the survey show that a significant proportion of people in Nigeria are still at risk of SARS-CoV-2 infection and therefore, COVID-19. It is very important that Nigerians continue to adhere to public health and social measures including regular handwashing, proper use of face masks and physical distancing.
The United States Centers for Disease Control and Prevention (US-CDC), the University College London (supported by Bill and Melinda Gates Foundation), the University of Maryland, Baltimore (UMB), and the respective State Ministries of Health supported implementation of the survey.
The survey is being expanded to more states with a priority to capture information from states in the North-West and South-South geopolitical zones which were not included in the initial round of surveys.
The Federal Ministry of Health, its agencies NCDC and NIMR as well as the PTF-COVID-19 remain committed to strengthening Nigeria’s response to COVID-19 and controlling the outbreak.