Coronavirus Disease 2019 Vaccination Coverage and Seropositivity amongst Nigerians 18 Years Old and Above.

BACKGROUND: This was a cross-sectional community-based survey to study the prevalence of serum antibodies against the severe acute respiratory syndrome coronavirus 1 (SARS-COV-1) and determine possible source of antibodies as to whether from vaccination or from natural infection as well as attempt to compare antibody levels in response to the different four types of vaccines administered in Nigeria. METHODS: A cross-sectional community-based study of the prevalence of serum antibodies against all four vaccine types used in Nigeria amongst a representative sample of people aged 18 years and above in the six geopolitical zones of the country using a multistage sampling technique covering 12 states of the country with two states being randomly selected from each geopolitical zone. High-throughput Roche electrochemiluminescence immunoassay system (Elecsys Anti-SARS-COV-1 Cobas) was used for qualitative and quantitative detection of antibodies to SARS-COV-1 in human plasma. RESULTS: There was no statistically significant difference between the proportions with seropositivity for both the vaccinated and the unvaccinated (P = 0.95). The nucleocapsid antibody (anti-Nc) titres were similar in both the vaccinated and the unvaccinated, whereas the Spike protein antibody (anti-S) titres were significantly higher amongst the vaccinated than amongst the unvaccinated. Antibody levels in subjects who received different vaccines were compared to provide information for policy. CONCLUSION: While only 45.9% of the subjects were reported to have been vaccinated, 98.7% of the subjects had had contact with the SARS-COV-1 as evidenced by the presence of nucleocapsid (NC) antibodies in their plasma. The 1.3% who had not been exposed to the virus, had spike protein antibodies which most likely resulted from vaccination in the absence of NC antibodies. Successive vaccination and booster doses either through heterogeneous or homologous vaccines increased antibody titres, and this stimulation of immune memory may offer greater protection against coronavirus disease 2019.

Prevalence of Chronic Pulmonary Aspergillosis in Two (2) Tuberculosis Treatment Clinics in Lagos, Nigeria: A Prospective Longitudinal Study.

Background: Chronic pulmonary aspergillosis (CPA) is an underrecognized but common complication of pulmonary tuberculosis. In Nigeria, a tuberculosis-endemic country, there is currently no provision to monitor the development of CPA in patients treated for tuberculosis. This study determined the prevalence and incidence of CPA in Lagos, Nigeria. Methods: A prospective longitudinal study of patients with previously managed tuberculosis was conducted between June 2021 and May 2022. The study cohorts were assessed at 3-month intervals, and the following were collected: sociodemographic data, chest radiographic findings, sputum samples for fungal culture, and venous blood samples for Aspergillus immunoglobulin G estimation. CPA cases were determined using the case definition for resource-constrained countries. Descriptive and inferential statistics were used, and significance was set at a probability of 5% (P < .05). Results: Of the 141 patients recruited, 79 (56.0%) were in the retreatment and 62 (44.0%) in the posttreatment tuberculosis group. The median age (interquartile range) was 40 (30-52) years, with a male-to-female ratio of 1.1:1. Ninety-seven patients (69%) had a GeneXpert test done, of whom 63 (64.9%) were GeneXpert negative. Cough was the most common symptom, with 15 (11%) patients having hemoptysis. The rate of CPA increased steadily as the study progressed: 44 (31.2%) at commencement, 45 (34.9%) at 3 months, 49 (42.6%) at 6 months, and 51 (54.3%) at 9 months. Thus, the overall prevalence of CPA was 49.7%, and the incidence was 6.1%. Conclusions: CPA is common in Nigeria and its true burden may still be underestimated. Increased awareness of CPA as a posttuberculosis lung disease is advocated. Evaluation for CPA should be incorporated in patients' work-up for tuberculosis.

High SARS-CoV-2 seroprevalence in Lagos, Nigeria with robust antibody and cellular immune responses.

Background: Early evidence suggested that the impact of the COVID-19 pandemic was less severe in Africa compared to other parts of the world. However, more recent studies indicate higher SARS-CoV-2 infection and COVID-19 mortality rates on the continent than previously documented. Research is needed to better understand SARS-CoV-2 infection and immunity in Africa. Methods: In early 2021, we studied the immune responses in healthcare workers (HCWs) at Lagos University Teaching Hospital (n = 134) and Oxford-AstraZeneca COVID-19 vaccine recipients from the general population (n = 116) across five local government areas (LGAs) in Lagos State, Nigeria. Western blots were used to simultaneously detect SARS-CoV-2 spike and nucleocapsid (N) antibodies (n = 250), and stimulation of peripheral blood mononuclear cells with N followed by an IFN-γ ELISA was used to examine T cell responses (n = 114). Results: Antibody data demonstrated high SARS-CoV-2 seroprevalence of 72·4% (97/134) in HCWs and 60·3% (70/116) in the general population. Antibodies directed to only SARS-CoV-2 N, suggesting pre-existing coronavirus immunity, were seen in 9·7% (13/134) of HCWs and 15·5% (18/116) of the general population. T cell responses against SARS-CoV-2 N (n = 114) were robust in detecting exposure to the virus, demonstrating 87·5% sensitivity and 92·9% specificity in a subset of control samples tested. T cell responses against SARS-CoV-2 N were also observed in 83.3% of individuals with N-only antibodies, further suggesting that prior non-SARS-CoV-2 coronavirus infection may provide cellular immunity to SARS-CoV-2. Conclusions: These results have important implications for understanding the paradoxically high SARS-CoV-2 infection with low mortality rate in Africa and supports the need to better understand the implications of SARS-CoV-2 cellular immunity.

Standardization of Aspergillus IgG diagnostic cutoff in Nigerians.

BACKGROUND AND OBJECTIVES: Commercial Aspergillus IgG antibody assays have become pivotal in the current diagnosis of chronic pulmonary aspergillosis (CPA). However, diagnostic cutoffs have been found to vary from manufactures' recommendations in different settings. This study aimed to establish the Aspergillus IgG reference range among Nigerians and determine a diagnostic cutoff for CPA. METHODS: Sera from 519 prospectively recruited healthy blood donors and 39 previously confirmed cases of CPA were analysed for Aspergillus IgG levels using the Bordier test kit (Bordier Affinity Products SA, Crissier, Switzerland). Accuracy versus cutoff profile and receiver operating characteristics (ROC) curve were analysed for both CPA cases and controls using the R-Studio (2020), (Window desktop, version 4.0.2 software with R packages "nnet" and "ROCR"). RESULTS: Among healthy blood donors, 141 (27.2%) were aged 16-25 years with median (interquartile range, IQR) of 22 (20-24) years; 304 (58.6%) were aged 26-40 years with median (IQR) of 32 (29-36) years; while 74 (14.2%) were aged 41-60 years with median (IQR) of 46 (44-49.75). Median IgG level in respective age groups were 0.069 (0.009-0.181), 0.044 (0.014-0.202) and 0.056 (0.01-0.265) with no significant difference found in the three age categories (p = 0.69). The overall diagnostic cutoff for the diagnosis of CPA was 0.821 with an accuracy of 97.1% and area under the curve (AUC) = 0.986. CONCLUSION: The optimal diagnostic cutoff for diagnosing CPA in Nigerians using the Bordier kit was 0.821 which is lower than the manufacturer's recommended cutoff of 1.0. The determination of this cutoff among Nigerians will significantly enhance accurate identification of CPA and assessment of its true burden in Nigeria.

Cryptococcal Antigenemia in Nigerian Patients With Advanced Human Immunodeficiency Virus: Influence of Antiretroviral Therapy Adherence.

Background. Cryptococcal meningitis has a high mortality in human immunodeficiency virus (HIV)-infected persons in Africa. This is preventable with early screening and preemptive therapy. We evaluated the prevalence of cryptococcal disease by antigen testing, possible associated factors, and outcomes in HIV-infected patients being managed in a tertiary hospital in Lagos, Nigeria. Methods. Sera were collected from 214 consenting HIV-infected participants with CD4(+) counts <250 cells/mm(3), irrespective of their antiretroviral therapy (ART) status, between November 2014 and May 2015. A cryptococcal antigen (CrAg) lateral flow assay was used for testing. Pertinent clinical data were obtained from patients and their case notes. Results. Of the 214 participants, females (124; 57.9%) outnumbered males. Mean age was 41.3 ± 9.4 (standard deviation) years. The majority (204; 95.3%) were ART experienced. The median CD4(+) cell count was 160 cells/mm(3) (interquartile range, 90-210). The overall seroprevalence of cryptococcal antigenemia was 8.9% (19 of 214); 6 of 61 (9.8%) in those with CD4(+) cell counts <100 cells/mm(3), 4 of 80 (5.0%) in the 100-200 group, and 9 of 73 (12.3%) in 200-250 cells/mm(3) group. Among ART-naive patients, 1 of 10 (10%) was CrAg positive. Twenty-seven of 214 (12.6%) had associated oral thrush. Potential baseline meningitis symptoms (3 of 214 [1.4%] experienced neck pain or stiffness and 21 of 214 [9.8%] experienced headache) were common in the study group, but the result was not statistically significant in relation to CrAg positivity. Two of 19 (10.5%) CrAg-positive patients died, 10 of 19 (52.6%) were lost to follow up, and 7 of 19 (36.8%) were alive. Empirical fluconazole was routinely given to those with low CD4 counts <100 cells/mm(3), which was unrelated to CrAg positivity (P = .018). Conclusions. We report a prevalence of 8.9% cryptococcal antigenemia in a setting where first-line antifungals are not readily available. We recommend CrAg screening for HIV-infected patients, even for patients on ART.