A contemporary review of clade-specific virological differences in monkeypox viruses.

BACKGROUND: Monkeypox virus (MPXV) is an emerging zoonotic virus that has had on-going public health impacts in endemic regions of Central and West Africa for over a half-century. Historically, the MPXV clade endemic in regions of Central Africa is associated with higher morbidity and mortality as compared with the clade endemic in West Africa. OBJECTIVES: Here, we review the virological characteristics of MPXV and discuss potential relationships between virulence factors and clade- (and subclade-) specific differences in virulence and transmission patterns. SOURCES: Targeted search was conducted in PubMed using ((monkeypox virus) OR (Orthopoxvirus)) AND (zoonosis)) OR ((monkeypox) OR (human mpox). CONTENT: Forty-seven references were considered that included three publicly available data reports and/or press releases, one book chapter, and 44 published manuscripts. IMPLICATIONS: Although zoonosis has been historically linked to emergence events in humans, epidemiological analyses of more recent outbreaks have identified increasing frequencies of human-to-human transmission. Furthermore, viral transmission during the 2022 global human mpox outbreak, caused by a recently identified MPXV subclade, has relied exclusively on human-to-human contact with no known zoonotic link.

A continent-wide effort and solidarity at curbing COVID-19 pandemic: the Africa task force for novel coronavirus (AFTCOR) infection prevention and control technical working group's experience.

A continent-wide Africa Task Force for Coronavirus with its six technical working groups was formed to prepare adequately and respond to the novel Coronavirus disease (COVID-19) outbreak in Africa. This research in practice article aimed to describe how the infection prevention and control (IPC) technical working group (TWG) supported Africa Centre for Disease Control and Prevention (Africa CDC) in preparedness and response to COVID-19 on the continent. To effectively address the multifaceted IPC TWG mandate of organizing training and implementing rigorous IPC measures at healthcare service delivery points, the working group was sub-divided into four sub-groups-Guidelines, Training, Research, and Logistics. The action framework was used to describe the experiences of each subgroup. The guidelines subgroup developed 14 guidance documents and two advisories; all of which were published in English. In addition, five of these documents were translated and published in Arabic, while three others were translated and published in French and Portuguese. Challenges faced in the guidelines subgroup included the primary development of the Africa CDC website in English, and the need to revise previously issued guidelines. The training subgroup engaged the Infection Control Africa Network as technical experts to carry out in-person training of IPC focal persons and port health personnel across the African continent. Challenges faced included the difficulty in conducting face-to-face IPC training and onsite technical support due to the lockdown. The research subgroup developed an interactive COVID-19 Research Tracker on the Africa CDC website and conducted a context-based operation and implementation research. The lack of understanding of Africa CDC's capacity to lead her own research was the major challenge faced by the research subgroup. The logistics subgroup assisted African Union (AU) member states to identify their IPC supply needs through capacity building for IPC quantification. A notable challenge faced by the logistics subgroup was the initial lack of experts on IPC logistics and quantifications, which was later addressed by the recruitment of professionals. In conclusion, IPC cannot be built overnight nor can it be promoted abruptly during outbreaks of diseases. Thus, the Africa CDC should build strong national IPC programmes and support such programmes with trained and competent professionals.

Mpox in pregnancy: Management, risks and challenges in Africa and lessons from the COVID-19 pandemic.

Data on mpox in pregnancy are currently limited. Historically, only 65 cases in pregnancy have been reported globally since mpox was discovered in 1958. This includes 59 cases in the current outbreak. Vertical transmission was confirmed in one patient. Pregnant women are at high risk of severe disease owing to immunological and hormonal changes that increase susceptibility to infections in pregnancy. African women appear to be at higher risk of mpox infection and adverse outcomes in pregnancy for epidemiological and immunologic reasons, in addition to the background high rates of adverse feto-maternal outcomes in the region. This risk is potentially heightened during the COVID-19 pandemic due to the possibility of mpox virus exportation/importation as a result of the lifting of movement restrictions and trans-border travels between countries affected by the current outbreak. Furthermore, coinfection with mpox and COVID-19 in pregnancy is possible, and the clinical features of both conditions may overlap. Challenges of diagnosis and management of mpox in pregnancy in Africa include patients concealing their travel history from healthcare providers and absconding from/evading isolation after diagnosis, shortage of personal protective equipment and polymerase chain reaction testing facilities for diagnosis, vaccine hesitancy/resistance, and poor disease notification systems. There is a need for local, regional and global support to strengthen the capacity of African countries to address these challenges and potentially reduce the disease burden among pregnant women in the continent.

High Genetic Diversity of Carbapenem-Resistant Acinetobacter baumannii Isolates Recovered in Nigerian Hospitals in 2016 to 2020.

Acinetobacter baumannii causes difficult-to-treat infections mostly among immunocompromised patients. Clinically relevant A. baumannii lineages and their carbapenem resistance mechanisms are sparsely described in Nigeria. This study aimed to characterize the diversity and genetic mechanisms of carbapenem resistance among A. baumannii strains isolated from hospitals in southwestern Nigeria. We sequenced the genomes of all A. baumannii isolates submitted to Nigeria's antimicrobial resistance surveillance reference laboratory between 2016 and 2020 on an Illumina platform and performed in silico genomic characterization. Selected strains were sequenced using the Oxford Nanopore technology to characterize the genetic context of carbapenem resistance genes. The 86 A. baumannii isolates were phylogenetically diverse and belonged to 35 distinct Oxford sequence types (oxfSTs), 16 of which were novel, and 28 Institut Pasteur STs (pasSTs). Thirty-eight (44.2%) isolates belonged to none of the known international clones (ICs). Over 50% of the isolates were phenotypically resistant to 10 of 12 tested antimicrobials. The majority (n = 54) of the isolates were carbapenem resistant, particularly the IC7 (pasST25; 100%) and IC9 (pasST85; >91.7%) strains. blaOXA-23 (34.9%) and blaNDM-1 (27.9%) were the most common carbapenem resistance genes detected. All blaOXA-23 genes were carried on Tn2006 or Tn2006-like transposons. Our findings suggest that a 10-kb Tn125 composite transposon is the primary means of blaNDM-1 dissemination. Our findings highlight an increase in blaNDM-1 prevalence and the widespread transposon-facilitated dissemination of carbapenemase genes in diverse A. baumannii lineages in southwestern Nigeria. We make the case for improving surveillance of these pathogens in Nigeria and other understudied settings. IMPORTANCE Acinetobacter baumannii bacteria are increasingly clinically relevant due to their propensity to harbor genes conferring resistance to multiple antimicrobials, as well as their ability to persist and disseminate in hospital environments and cause difficult-to-treat nosocomial infections. Little is known about the molecular epidemiology and antimicrobial resistance profiles of these organisms in Nigeria, largely due to limited capacity for their isolation, identification, and antimicrobial susceptibility testing. Our study characterized the diversity and antimicrobial resistance profiles of clinical A. baumannii in southwestern Nigeria using whole-genome sequencing. We also identified the key genetic elements facilitating the dissemination of carbapenem resistance genes within this species. This study provides key insights into the clinical burden and population dynamics of A. baumannii in hospitals in Nigeria and highlights the importance of routine whole-genome sequencing-based surveillance of this and other previously understudied pathogens in Nigeria and other similar settings.

Training a Continent: A Process Evaluation of Virtual Training on Infection Prevention and Control in Africa During COVID-19.

BACKGROUND: Strengthening infection prevention and control (IPC) capacity was identified as a key intervention to prepare African Union member states to curb the COVID-19 pandemic. As part of the Africa Taskforce for Coronavirus, which helped implement the Africa Joint Continental Strategy for COVID-19 Outbreak response, the IPC Technical Working Group (IPC TWG) was convened to coordinate the development of IPC core components for preparedness, response, and recovery from COVID-19. As part of the IPC TWG's work, the Africa Centres for Disease Control and Prevention, in collaboration with the Infection Control Africa Network, delivered virtual IPC training sessions targeted to African Union member states. We aimed to undertake a process evaluation of this training to inform and improve both ongoing and future programming. METHODS: The scope of the evaluation was agreed upon through discussion with the training organizers and advisory members and a design workshop. A mixed-methods approach was used; data collection was partly prospective and partly retrospective due to the rapid start of some of the training activities. Existing available data included: usage analytics, the content of questions posed during the webinar and community of practice, and participant feedback survey results. In addition, in-depth qualitative interviews were conducted with a sample of webinar participants. RESULTS: The rapid development of this training was efficient and responsive. The training reached more than 3,000 participants across the 2 rounds, but the numbers varied substantially by location. Participants engaged well during the question period during each webinar, but the asynchronous community of practice was less utilized during the evaluation time frame. Many participants appreciated the African focus of the webinars and gave positive feedback on the practical and context-specific content. CONCLUSIONS: The move toward online training provides an important opportunity to improve IPC across the African continent.

Effect of Nigeria Presidential Task Force on COVID-19 Pandemic, Nigeria.

Nigeria had a confirmed case of COVID-19 on February 28, 2020. On March 17, 2020, the Nigerian Government inaugurated the Presidential Task Force (PTF) on COVID-19 to coordinate the country's multisectoral intergovernmental response. The PTF developed the National COVID-19 Multisectoral Pandemic Response Plan as the blueprint for implementing the response plans. The PTF provided funding, coordination, and governance for the public health response and executed resource mobilization and social welfare support, establishing the framework for containment measures and economic reopening. Despite the challenges of a weak healthcare infrastructure, staff shortages, logistic issues, commodity shortages, currency devaluation, and varying state government cooperation, high-level multisectoral PTF coordination contributed to minimizing the effects of the pandemic through early implementation of mitigation efforts, supported by a strong collaborative partnership with bilateral, multilateral, and private-sector organizations. We describe the lessons learned from the PTF COVID-19 for future multisectoral public health response.

Drug-resistant bacterial infections: We need urgent action and investment that focus on the weakest link.

Despite high mortality and morbidity, drug-resistant bacterial infections remain the forgotten pandemic. We argue for strengthening of diagnostics, WASH (water, sanitation, and hygiene) and infection prevention and control to reduce drug-resistant infections, as an integral part of sustainable high-quality health services, particularly in low- and middle-income countries.

Genomic characterization of invasive typhoidal and non-typhoidal Salmonella in southwestern Nigeria.

BACKGROUND: Salmonellosis causes significant morbidity and mortality in Africa. Information on lineages of invasive Salmonella circulating in Nigeria is sparse. METHODS: Salmonella enterica isolated from blood (n = 60) and cerebrospinal fluid (CSF, n = 3) between 2016 and 2020 from five tertiary hospitals in southwest Nigeria were antimicrobial susceptibility-tested and Illumina-sequenced. Genomes were analysed using publicly-available bioinformatic tools. RESULTS: Isolates and sequence types (STs) from blood were S. Typhi [ST1, n = 1 and ST2, n = 43] and invasive non-typhoidal Salmonella (iNTS) (S. Enteritidis [ST11, n = 7], S. Durham [ST10, n = 2], S. Rissen [ST8756, n = 2], S. Chester [ST2063, n = 1], S. Dublin [ST10, n = 1], S. Infantis [ST603, n = 1], S. Telelkebir [ST8757, n = 1] and S. Typhimurium [ST313, n = 1]). S. Typhi ST2 (n = 2) and S. Adabraka ST8757 (n = 1) were recovered from CSF. Most S. Typhi belonged to genotype 3.1.1 (n = 44), carried an IncY plasmid, had several antibiotic resistance genes (ARGs) including blaTEM-1 (n = 38), aph(6)-Id (n = 32), tet(A) (n = 33), sul2 (n = 32), dfrA14 (n = 30) as well as quinolone resistance-conferring gyrA_S83Y single-nucleotide polymorphisms (n = 37). All S. Enteritidis harboured aph(3")-Ib, blaTEM-1, catA1, dfrA7, sul1, sul2, tet(B) genes, and a single ARG, qnrB19, was detected in S. Telelkebir. Typhoidal toxins cdtB, pltA and pltB were detected in S. Typhi, Rissen, Chester, and Telelkebir. CONCLUSION: Most invasive salmonelloses in southwest Nigeria are vaccine-preventable infections due to multidrug-resistant, West African dominant S. Typhi lineage 3.1.1. Invasive NTS serovars, including some harbouring typhoidal toxin or resistance genes, represented a third of the isolates emphasizing the need for better diagnosis and surveillance.

An assessment of infection prevention and control preparedness of healthcare facilities in Nigeria in the early phase of the COVID-19 pandemic (February-May 2020).

Background: Infection prevention and control (IPC) activities play a large role in preventing the transmission of SARS-CoV-2 in healthcare settings. This study describes the state of IPC preparedness within health facilities in Nigeria during the early phase of coronavirus disease (COVID-19) pandemic. Methods: We carried out a cross sectional study of health facilities across Nigeria using a COVID-19 IPC checklist adapted from the U.S Centers for Disease Control and Prevention. The IPC aspects assessed were the existence of IPC committee and teams with terms of reference and workplans, IPC training, availability of personal protective equipment and having systems in place for screening, isolation and notification of COVID-19 patients. Existence of the assessed aspects was regarded as preparedness in that aspect. Results: In total, 461 health facilities comprising, 350 (75.9%) private and 111 (24.1%) public health facilities participated. Only 19 (4.1%) health facilities were COVID-19 treatment centres with 68% of these being public health facilities. Public health facilities were better prepared in the areas of IPC programme with 69.7% of them having an IPC focal point versus 32.3% of private facilities. More public facilities (59.6%) had an IPC workplan versus 26.8% of private facilities. Neither the public nor the private facilities were adequately prepared for triaging, screening, and notifying suspected cases, as well as having trained staff and equipment to implement triaging. Conclusions: The results highlight the need for government, organisations and policymakers to establish conducive IPC structures to reduce the risk of COVID-19 transmission in healthcare settings.

A Better Disinfectant for Low-Resourced Hospitals? A Multi-Period Cluster Randomised Trial Comparing Hypochlorous Acid with Sodium Hypochlorite in Nigerian Hospitals: The EWASH Trial.

Environmental hygiene in hospitals is a major challenge worldwide. Low-resourced hospitals in African countries continue to rely on sodium hypochlorite (NaOCl) as major disinfectant. However, NaOCl has several limitations such as the need for daily dilution, irritation, and corrosion. Hypochlorous acid (HOCl) is an innovative surface disinfectant produced by saline electrolysis with a much higher safety profile. We assessed non-inferiority of HOCl against standard NaOCl for surface disinfection in two hospitals in Abuja, Nigeria using a double-blind multi-period randomised cross-over study. Microbiological cleanliness [Aerobic Colony Counts (ACC)] was measured using dipslides. We aggregated data at the cluster-period level and fitted a linear regression. Microbiological cleanliness was high for both disinfectant (84.8% HOCl; 87.3% NaOCl). No evidence of a significant difference between the two products was found (RD = 2%, 90%CI: -5.1%-+0.4%; p-value = 0.163). We cannot rule out the possibility of HOCl being inferior by up to 5.1 percentage points and hence we did not strictly meet the non-inferiority margin we set ourselves. However, even a maximum difference of 5.1% in favour of sodium hypochlorite would not suggest there is a clinically relevant difference between the two products. We demonstrated that HOCl and NaOCl have a similar efficacy in achieving microbiological cleanliness, with HOCl acting at a lower concentration. With a better safety profile, and potential applicability across many healthcare uses, HOCl provides an attractive and potentially cost-efficient alternative to sodium hypochlorite in low resource settings.

Baseline study for improving diagnostic stewardship at secondary health care facilities in Nigeria.

BACKGROUND: Blood culture diagnostics are critical tools for sepsis management and antimicrobial resistance (AMR) surveillance. A baseline study was conducted to assess reported sepsis case finding, blood culture diagnostics, antimicrobial susceptibility testing (AST) and antimicrobial use at secondary health care facilities to inform the development of diagnostic stewardship improvement strategies in Nigeria. METHODS: A cross-sectional online survey was conducted among 25 public secondary health care facilities in Abuja, Federal Capital Territory (FCT) and Lagos State in Nigeria to evaluate the capacity for pathogen identification and AST. Data were then prospectively extracted on all patients with reported suspected sepsis from electronic medical records from selected departments at two facilities in the Federal Capital Territory from October 2020 to May 2021 to further assess practices concerning sepsis case-finding, clinical examination findings, samples requested, and laboratory test results. Data were descriptively analysed, and a multivariate logistic regression analysis was conducted to determine factors associated with blood culture requests. RESULTS: In the online survey, 32% (8/25) of facilities reported performing blood cultures. Only one had access to a clinical microbiologist, and 28% (7/25) and 4% (1/25) used standard bacterial organisms for quality control of media and quality control strains for AST, respectively. At the two facilities where data abstraction was performed, the incidence of suspected sepsis cases reported was 7.1% (2924/41066). A majority of these patients came from the paediatrics department and were outpatients, and the median age was two years. Most did not have vital signs and major foci of infection documented. Blood cultures were only requested for 2.7% (80/2924) of patients, of which twelve were positive for bacteria, mainly Staphylococcus aureus. No clinical breakpoints were used for AST. Inpatients (adjusted odds ratio [aOR]: 7.5, 95% CI: 4.6-12.3) and patients from the urban health care facility (aOR:16.9, 95% CI: 8.1-41.4) were significantly more likely to have a blood culture requested. CONCLUSION: Low blood culture utilisation remains a key challenge in Nigeria. This has implications for patient care, AMR surveillance and antibiotic use. Diagnostic stewardship strategies should focus on improving access to clinical microbiology expertise, practical guidance on sepsis case finding and improving blood culture utilisation and diagnostics.

Analysis of sociodemographic and clinical factors associated with Lassa fever disease and mortality in Nigeria.

Over past decades, there has been increasing geographical spread of Lassa fever (LF) cases across Nigeria and other countries in West Africa. This increase has been associated with significant morbidity and mortality despite increasing focus on the disease by both local and international scientists. Many of these studies on LF have been limited to few specialised centres in the country. This study was done to identify sociodemographic and clinical predictors of LF disease and related deaths across Nigeria. We analysed retrospective surveillance data on suspected LF cases collected during January-June 2018 and 2019. Multivariable logistic regression analyses were used to identify the factors independently associated with laboratory-confirmed LF diagnosis, and with LF-related deaths. There were confirmed 815 of 1991 suspected LF cases with complete records during this period. Of these, 724/815 confirmed cases had known clinical outcomes, of whom 100 died. LF confirmation was associated with presentation of gastrointestinal tract (aOR 3.47, 95% CI: 2.79-4.32), ear, nose and throat (aOR 2.73, 95% CI: 1.80-4.15), general systemic (aOR 2.12, 95% CI: 1.65-2.70) and chest/respiratory (aOR 1.71, 95% CI: 1.28-2.29) symptoms. Other factors were being male (aOR 1.32, 95% CI: 1.06-1.63), doing business/trading (aOR 2.16, 95% CI: 1.47-3.16) and farming (aOR 1.73, 95% CI: 1.12-2.68). Factors associated with LF mortality were a one-year increase in age (aOR 1.03, 95% CI: 1.01-1.04), bleeding (aOR 2.07, 95% CI: 1.07-4.00), and central nervous manifestations (aOR 5.02, 95% CI: 3.12-10.16). Diverse factors were associated with both LF disease and related death. A closer look at patterns of clinical variables would be helpful to support early detection and management of cases. The findings would also be useful for planning preparedness and response interventions against LF in the country and region.

Evaluation of infection prevention and control practices in Lassa fever treatment centers in north-central Nigeria during an ongoing Lassa fever outbreak.

BACKGROUND: Outbreaks of Lassa fever (LF) in Nigeria have become more frequent, with increasing more healthcare worker infections. Prevention of infection is dependent on strict compliance to infection prevention and control (IPC) practices in treatment centres where patients are managed. OBJECTIVE: To evaluate IPC practices during an ongoing LF outbreak in the two major tertiary hospitals serving as the referral LF treatment centres in the north-central region of Nigeria. METHODS: This cross-sectional survey was carried out by the IPC subteam of the National Rapid Response Team of the Nigeria Centre for Disease Control (NCDC) deployed to Plateau State, north-central Nigeria during the 2019 LF outbreak. Information on IPC in these facilities was collected using the NCDC viral haemorrhagic fevers (VHFs) isolation and treatment facility IPC survey tool. RESULTS: Both treatment centres had national VHF IPC isolation guidelines and few health workers had received IPC training. In both centres, there were no clearly demarcated entry points for staff going into clinical areas after putting on personal protective equipment, and there were also no standard operating procedures in place for reporting occupational exposure of staff to infected blood or body fluids in both centres. DISCUSSION: The LF treatment centers located in Plateau State during the 2019 LF outbreak were not fully implementing the national VHF IPC guidelines. Periodic assessments of IPC are recommended for proper management of cases and effective control of LF in the State.

Epidemiological comparison of the first and second waves of the COVID-19 pandemic in Nigeria, February 2020-April 2021.

BACKGROUND: With reports of surges in COVID-19 case numbers across over 50 countries, country-level epidemiological analysis is required to inform context-appropriate response strategies for containment and mitigation of the outbreak. We aimed to compare the epidemiological features of the first and second waves of COVID-19 in Nigeria. METHODS: We conducted a retrospective analysis of the Surveillance Outbreak Response Management and Analysis System data of the first and second epidemiological waves, which were between 27 February and 24 October 2020, and 25 October 2020 to 3 April 2021, respectively. Descriptive statistical measures including frequencies and percentages, test positivity rate (TPR), cumulative incidence (CI) and case fatality rates (CFRs) were compared. A p value of <0.05 was considered statistically significant. All statistical analyses were carried out in STATA V.13. RESULTS: There were 802 143 tests recorded during the study period (362 550 and 439 593 in the first and second waves, respectively). Of these, 66 121 (18.2%) and 91 644 (20.8%) tested positive in the first and second waves, respectively. There was a 21.3% increase in the number of tests conducted in the second wave with TPR increasing by 14.3%. CI during the first and second waves were 30.3/100 000 and 42.0/100 000 respectively. During the second wave, confirmed COVID-19 cases increased among females and people 30 years old or younger and decreased among urban residents and individuals with travel history within 14 days of sample collection (p value <0.001). Most confirmed cases were asymptomatic at diagnosis during both waves: 74.9% in the first wave; 79.7% in the second wave. CFR decreased during the second wave (0.7%) compared with the first wave (1.8%). CONCLUSION: Nigeria experienced a larger but less severe second wave of COVID-19. Continued implementation of public health and social measures is needed to mitigate the resurgence of another wave.

The One Health approach to incident management of the 2019 Lassa fever outbreak response in Nigeria.

Globally, effective emergency response to disease outbreaks is usually affected by weak coordination. However, coordination using an incident management system (IMS) in line with a One Health approach involving human, environment, and animal health with collaborations between government and non-governmental agencies result in improved response outcome for zoonotic diseases such as Lassa fever (LF). We provide an overview of the 2019 LF outbreak response in Nigeria using the IMS and One Health approach. The response was coordinated via ten Emergency Operation Centre (EOC) response pillars. Cardinal response activities included activation of EOC, development of an incident action plan, deployment of One Health rapid response teams to support affected states, mid-outbreak review and after-action review meetings. Between 1st January and 29th December 2019, of the 5057 people tested for LF, 833 were confirmed positive from 23 States, across 86 Local Government Areas. Of the 833 confirmed cases, 650 (78%) were from hotspot States of Edo (36%), Ondo (26%) and Ebonyi (16%). Those in the age-group 21-40 years (47%) were mostly affected, with a male to female ratio of 1:1. Twenty healthcare workers were affected. Two LF naïve states Kebbi and Zamfara, reported confirmed cases for the first time during this period. The outbreak peaked earlier in the year compared to previous years, and the emergency phase of the outbreak was declared over by epidemiological week 17 based on low national threshold composite indicators over a period of six consecutive weeks. Multisectoral and multidisciplinary strategic One Health EOC coordination at all levels facilitated the swift containment of Nigeria's large LF outbreak in 2019. It is therefore imperative to embrace One Health approach embedded within the EOC to holistically address the increasing LF incidence in Nigeria.

Assessing the capacity of symptom scores to predict COVID-19 positivity in Nigeria: a national derivation and validation cohort study.

OBJECTIVES: This study aimed to develop and validate a symptom prediction tool for COVID-19 test positivity in Nigeria. DESIGN: Predictive modelling study. SETTING: All Nigeria States and the Federal Capital Territory. PARTICIPANTS: A cohort of 43 221 individuals within the national COVID-19 surveillance dataset from 27 February to 27 August 2020. Complete dataset was randomly split into two equal halves: derivation and validation datasets. Using the derivation dataset (n=21 477), backward multivariable logistic regression approach was used to identify symptoms positively associated with COVID-19 positivity (by real-time PCR) in children (≤17 years), adults (18-64 years) and elderly (≥65 years) patients separately. OUTCOME MEASURES: Weighted statistical and clinical scores based on beta regression coefficients and clinicians' judgements, respectively. Using the validation dataset (n=21 744), area under the receiver operating characteristic curve (AUROC) values were used to assess the predictive capacity of individual symptoms, unweighted score and the two weighted scores. RESULTS: Overall, 27.6% of children (4415/15 988), 34.6% of adults (9154/26 441) and 40.0% of elderly (317/792) that had been tested were positive for COVID-19. Best individual symptom predictor of COVID-19 positivity was loss of smell in children (AUROC 0.56, 95% CI 0.55 to 0.56), either fever or cough in adults (AUROC 0.57, 95% CI 0.56 to 0.58) and difficulty in breathing in the elderly (AUROC 0.53, 95% CI 0.48 to 0.58) patients. In children, adults and the elderly patients, all scoring approaches showed similar predictive performance. CONCLUSIONS: The predictive capacity of various symptom scores for COVID-19 positivity was poor overall. However, the findings could serve as an advocacy tool for more investments in resources for capacity strengthening of molecular testing for COVID-19 in Nigeria.