Saliva sample for detection of SARS-CoV-2: A possible alternative for mass testing.

Molecular diagnostic testing has played a critical role in the global response to the novel Coronavirus disease (COVID-19) pandemic, since its first outbreak in late 2019. At the inception of the COVID-19 pandemic, nasopharyngeal swab sample analysis for COVID-19 diagnosis using the real-time polymerase chain reaction (RT-PCR) technique was the most widely used. However, due to the high cost and difficulty of sample collection, the number of available sample types for COVID-19 diagnosis is rapidly increasing, as is the COVID-19 diagnostic literature. The use of nasal swabs, saliva, and oral fluids as viable sample options for the effective detection of SARS-CoV-2 has been implemented successfully in different settings since 2020. These alternative sample type provides a plethora of advantages including decreasing the high exposure risk to frontline workers, enhancing the chances of home self-sampling, reducing the cost, and significantly increasing testing capacity. This study sought to ascertain the effectiveness of Saliva samples as an alternative for COVID-19 diagnosis in Nigeria. Demographic data, paired samples of Nasopharyngeal Swab and Drooling Saliva were obtained from 309 consenting individuals aged 8-83 years presenting for COVID-19 testing. All samples were simultaneously assayed for the detection of SARS-CoV-2 RdRp, N, and E genes using the GeneFinder™ COVID-19 Plus RT-PCR test kit. Out of 309 participants, only 299 with valid RT-PCR results comprising 159 (53.2%) males and 140 (46.8%) females were analyzed in this study using the R Statistical package. Among the 299 samples analyzed, 39 (13.0%) had SARS-CoV-2 detected in at least one specimen type. Both swabs and saliva were positive in 20 (51.3%) participants. Ten participants (25.6%) had swab positive/saliva-negative results and 9 participants (23.1%) had saliva positive/swab-negative results. The percentage of positive and negative agreement of the saliva samples with the nasopharyngeal swab were 67% and 97% respectively with positive and negative predictive values as 69% and 96% respectively. The findings indicate that drooling saliva samples have good and comparable diagnostic accuracy to the nasopharyngeal swabs with moderate sensitivities and high specificities.

From Ebola to COVID-19: emergency preparedness and response plans and actions in Lagos, Nigeria.

BACKGROUND: Lagos state is the industrial nerve centre of Nigeria and was the epicentre of the 2014 Ebola outbreak in Nigeria as it is now for the current Coronavirus Disease (COVID-19) outbreak. This paper describes how the lessons learned from the Ebola outbreak in 2014 informed the emergency preparedness of the State ahead of the COVID-19 outbreak and guided response. DISCUSSION: Following the Ebola outbreak in 2014, the Lagos State government provided governance by developing a policy on emergency preparedness and biosecurity and provided oversight and coordination of emergency preparedness strategies. Capacities for emergency response were strengthened by training key staff, developing a robust surveillance system, and setting up a Biosafety Level 3 laboratory and biobank. Resource provision, in terms of finances and trained personnel for emergencies was prioritized by the government. With the onset of COVID-19, Lagos state was able to respond promptly to the outbreak using the centralized Incident Command Structure and the key activities of the Emergency Operations Centre. Contributory to effective response were partnerships with the private sectors, community engagement and political commitment. CONCLUSION: Using the lessons learned from the 2014 Ebola outbreak, Lagos State had gradually prepared its healthcare system for a pandemic such as COVID-19. The State needs to continue to expand its preparedness to be more resilient and future proof to respond to disease outbreaks. Looking beyond intra-state gains, lessons and identified best practices from the past and present should be shared with other states and countries.

Comparative performance of SARS-CoV-2 real-time PCR diagnostic assays on samples from Lagos, Nigeria.

A key element in containing the spread of the SARS-CoV-2 infection is quality diagnostics which is affected by several factors. We now report the comparative performance of five real-time diagnostic assays. Nasopharyngeal swab samples were obtained from persons seeking a diagnosis for SARS-CoV-2 infection in Lagos, Nigeria. The comparison was performed on the same negative, low, and high-positive sample set, with viral RNA extracted using the Qiagen Viral RNA Kit. All five assays are one-step reverse transcriptase real-time PCR assays. Testing was done according to each assay's manufacturer instructions for use using real-time PCR platforms. 63 samples were tested using the five qPCR assays, comprising of 15 negative samples, 15 positive samples (Ct = 16-30; one Ct = 35), and 33 samples with Tib MolBiol E-gene Ct value ranging from 36-41. All assays detected all high positive samples correctly. Three assays correctly identified all negative samples while two assays each failed to correctly identify one different negative sample. The consistent detection of positive samples at different Ct/Cq values gives an indication of when to repeat testing and/or establish more stringent in-house cut-off value. The varied performance of different diagnostic assays, mostly with emergency use approvals, for a novel virus is expected. Comparative assays' performance reported may guide laboratories to determine both their repeat testing Ct/Cq range and/or cut-off value.

Full length genomic sanger sequencing and phylogenetic analysis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Nigeria.

In an outbreak, effective detection of the aetiological agent(s) involved using molecular techniques is key to efficient diagnosis, early prevention and management of the spread. However, sequencing is necessary for mutation monitoring and tracking of clusters of transmission, development of diagnostics and for vaccines and drug development. Many sequencing methods are fast evolving to reduce test turn-around-time and to increase through-put compared to Sanger sequencing method; however, Sanger sequencing remains the gold standard for clinical research sequencing with its 99.99% accuracy This study sought to generate sequence data of SARS-CoV-2 using Sanger sequencing method and to characterize them for possible site(s) of mutations. About 30 pairs of primers were designed, synthesized, and optimized using endpoint PCR to generate amplicons for the full length of the virus. Cycle sequencing using BigDye Terminator v.3.1 and capillary gel electrophoresis on ABI 3130xl genetic analyser were performed according to the manufacturers' instructions. The sequence data generated were assembled and analysed for variations using DNASTAR Lasergene 17 SeqMan Ultra. Total length of 29,760bp of SARS-CoV-2 was assembled from the sample analysed and deposited in GenBank with accession number: MT576584. Blast result of the sequence assembly shows a 99.97% identity with the reference sequence. Variations were noticed at positions: nt201, nt2997, nt14368, nt16535, nt20334, and nt28841-28843, which caused amino acid alterations at the S (aa614) and N (aa203-204) regions. The mutations observed at S and N-gene in this study may be indicative of a gradual changes in the genetic coding of the virus hence, the need for active surveillance of the viral genome.

Predictive ability of symptomatology in COVID-19 during Active case search in Lagos State, Nigeria.

BACKGROUND: In April 2020, a community-based active case search surveillance system of coronavirus disease 2019 (COVID-19) was developed by the emergency outbreak committee in Lagos State. This followed the evidence of community transmission of coronavirus disease in the twenty Local Government Areas in Lagos State. This study assessed the value of respiratory and other symptoms in predicting positive SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR). It is hoped that if symptoms are predictive, they can be used in screening before testing. METHODS: Communities were included based on the alerts from community members through the rumour alert system set up by the state. All members of the households of the communities from where the alert came were eligible. Household members who declined to participate were excluded from the study. A standardised interviewer-administered electronic investigation form was used to collect sociodemographic information, clinical details and history for each possible case. Data was analysed to see the extent of agreement or correlation between reported symptoms and the results of PCR testing for SARS-COV-2. RESULTS: A total of 12,739 persons were interviewed. The most common symptoms were fever, general weakness, cough and difficulty in breathing. Different symptoms recorded different levels of sensitivity as follows: fever, 28.9%; cough, 21.7%; general body weakness, 10.9%; and sore throat, 10.9%. Sensitivity and specificity for fever, the most common symptom, were 28.3% and 50.2%, respectively, while similar parameters for general body weakness, the next most common symptom, were 10.9% and 73.2%, respectively. CONCLUSION: From these findings, the predictive ability of symptoms for COVID-19 diagnosis was extremely weak. It is unlikely that symptoms alone will suffice to predict COVID-19 in a patient. An additional measure, such as confirmatory test by RT-PCR testing, is necessary to confirm the disease.

Caesarean delivery of first prediagnosed COVID-19 pregnancy in Nigeria.

The COVID-19 pandemic is currently causing widespread infection and deaths around the world. Since the identification of the first case in Nigeria in February 2020, the number of confirmed cases has risen to over 9,800. Although pregnant women are not necessarily more susceptible to infection by the virus, changes to their immune system in pregnancy may be associated with more severe symptoms. Adverse maternal and perinatal outcomes have been reported among pregnant women with COVID-19 infection. However, literature is scarce on the peripartum management and pregnancy outcome of a pregnant woman with COVID-19 in sub-Saharan Africa. We report the first successful and uncomplicated caesarean delivery of a pregnant woman with COVID-19 infection in Nigeria.