SARS-CoV-2 genomic surveillance and reliability of PCR single point mutation assay (SNPsig® SARS-CoV-2 EscapePLEX CE) for the rapid detection of variants of concern in Cameroon

Background

Surveillance of SARS-CoV-2 variants of concern (VOCs) and lineages is crucial for decision-making. Our objective was to study the SARS-CoV-2 clade dynamics across epidemiological waves and evaluate the reliability of SNPsig® SARS-CoV-2 EscapePLEX CE in detecting VOCs in Cameroon.

Material and methods

A laboratory-based study was conducted on SARS-CoV-2 positive nasopharyngeal specimens cycle threshold (Ct)≤30 at the Chantal BIYA International Reference Centre in Yaoundé-Cameroon, between April-2020 to August-2022. Samples were analyzed in parallel with Sanger sequencing and (SNPsig® SARS-CoV-2 EscapePLEX CE), and performance characteristics were evaluated by Cohen's coefficient and McNemar test.

Results

Of the 130 sequences generated, SARS-CoV-2 clades during wave-1 (April-November 2020) showed 97 % (30/31) wild-type lineages and 3 % (1/31) Gamma-variant; wave-2 (December-2020 to May-2021), 25 % (4/16) Alpha-variant, 25 % (4/16) Beta-variant, 44 % (7/16) wild-type and 6 % (1/16) mu; wave-3 (June-October 2021), 94 % (27/29) Delta-variant, 3 % (1/29) Alpha-variant, 3 % (1/29) wild-type; wave-4 (November-2021 to August-2022), 98 % (53/54) Omicron-variant and 2 % (1/54) Delta-variant. Omicron sub-variants were BA.1 (47 %), BA.5 (34 %), BA.2 (13 %) and BA.4 (6 %). Globally, the two genotyping methods accurately identified the SARS-CoV-2 VOCs (P = 0.17, McNemar test; Ka = 0.67).

Conclusion

Genomic surveillance reveals a rapid dynamic in SARS-CoV-2 strains between epidemiological waves in Cameroon. For wide-spread variant surveillance in resource-limited settings, SNPsig® SARS-CoV-2 EscapePLEX CEkit represents a suitable tool, pending upgrading for distinguishing Omicron sub-lineages.

2020 Ebola virus disease outbreak in Équateur Province, Democratic Republic of the Congo: a retrospective genomic characterisation

BACKGROUND

The Democratic Republic of the Congo has had 15 Ebola virus disease (EVD) outbreaks, from 1976 to 2023. On June 1, 2020, the Democratic Republic of the Congo declared an outbreak of EVD in the western Équateur Province (11th outbreak), proximal to the 2018 Tumba and Bikoro outbreak and concurrent with an outbreak in the eastern Nord Kivu Province. In this Article, we assessed whether the 11th outbreak was genetically related to previous or concurrent EVD outbreaks and connected available epidemiological and genetic data to identify sources of possible zoonotic spillover, uncover additional unreported cases of nosocomial transmission, and provide a deeper investigation into the 11th outbreak.

METHODS

We analysed epidemiological factors from the 11th EVD outbreak to identify patient characteristics, epidemiological links, and transmission modes to explore virus spread through space, time, and age groups in the Équateur Province, Democratic Republic of the Congo. Trained field investigators and health professionals recorded data on suspected, probable, and confirmed cases, including demographic characteristics, possible exposures, symptom onset and signs and symptoms, and potentially exposed contacts. We used blood samples from individuals who were live suspected cases and oral swabs from individuals who were deceased to diagnose EVD. We applied whole-genome sequencing of 87 available Ebola virus genomes (from 130 individuals with EVD between May 19 and Sept 16, 2020), phylogenetic divergence versus time, and Bayesian reconstruction of phylogenetic trees to calculate viral substitution rates and study viral evolution. We linked the available epidemiological and genetic datasets to conduct a genomic and epidemiological study of the 11th EVD outbreak.

FINDINGS

Between May 19 and Sept 16, 2020, 130 EVD (119 confirmed and 11 probable) cases were reported across 13 Équateur Province health zones. The individual identified as the index case reported frequent consumption of bat meat, suggesting the outbreak started due to zoonotic spillover. Sequencing revealed two circulating Ebola virus variants associated with this outbreak-a Mbandaka variant associated with the majority (97%) of cases and a Tumba-like variant with similarity to the ninth EVD outbreak in 2018. The Tumba-like variant exhibited a reduced substitution rate, suggesting transmission from a previous survivor of EVD.

INTERPRETATION

Integrating genetic and epidemiological data allowed for investigative fact-checking and verified patient-reported sources of possible zoonotic spillover. These results demonstrate that rapid genetic sequencing combined with epidemiological data can inform responders of the mechanisms of viral spread, uncover novel transmission modes, and provide a deeper understanding of the outbreak, which is ultimately needed for infection prevention and control during outbreaks.

FUNDING

WHO and US Centers for Disease Control and Prevention.

Strengthening community-based surveillance: lessons learned from the 2018-2020 Democratic Republic of Congo (DRC) Ebola outbreak

INTRODUCTION

There has been little documentation of the large networks of community health workers that contributed to Ebola Virus Disease (EVD) surveillance during the 2018-2020 Democratic Republic of Congo (DRC) epidemic in the form of community-based surveillance (CBS). These networks, comprised entirely of local community members, were a critical and mostly unrecognized factor in ending the epidemic. Challenges with collection, compilation, and analysis of CBS data have made their contribution difficult to quantify. From November 2019 to March 2020, the DRC Ministry of Health (MoH), the World Health Organization (WHO), and Médecins Sans Frontières (MSF) worked with communities to strengthen existing EVD CBS in two key health areas in Ituri Province, DRC. We describe CBS strengthening activities, detail collaboration with communities and present results of these efforts. We also provide lessons learned to inform future outbreak responses.

METHODS

As the foundation of CBS, community health workers (CHW) completed training to identify and report patients who met the EVD alert definitions. Alerts were investigated and if validated, the patient was sent for isolation and EVD testing. Community members provided early and ongoing input to the CBS system. We established a predefined ratio of community- elected CHW, allocated by population, to assure equal and adequate coverage across areas. Strong performing CHW or local leaders managed the CHWs, providing a robust supervision structure. We made additional efforts to integrate rural villages, revised tools to lighten the reporting burden and focused analysis on key indicators. Phased roll-out of activities ensured time for community discussion and approval. An integrated treatment center (ITC) combined EVD testing and isolation with free primary health care (PHC), referral services, and an ambulance network.

RESULTS

A total of 247 CHW and supervisors completed training. CBS had a retention rate of 94.3% (n = 233) with an average daily reporting rate of 97.4% (range 75.0-100.0%). Local chiefs and community leaders participated in activities from the early stages. Community feedback, including recommendations to add additional CHW, run separate meetings in rural villages, and strengthen PHC services, improved system coverage and performance. Of 6,711 community referrals made, 98.1% (n = 6,583) were classified as alerts. Of the alerts, 97.4% (n = 6,410) were investigated and 3.0% (n = 190) were validated. Of the community referrals, 73.1% (n = 4,905) arrived for care at the ITC. The contribution of CBS to total alerts in the surveillance system increased from an average of 47.3% in the four weeks prior to system strengthening to 69.0% after. In one of the two health areas, insufficient reporting in rural villages suggested inadequate coverage, with 8.3% of the total population contributing 6.1% of alerts.

DISCUSSION

CBS demonstrated the capacity of community networks to improve early disease detection and expand access to healthcare. Early and consistent community involvement proved vital to CBS, as measured by system performance, local acceptance of EVD activities, and health service provision. The CBS system had high reporting rates, number of alerts signaled, proportion of alerts investigated, and proportion of community referrals that arrived for care. The change in contribution of CBS to total alerts may have been due in part to system strengthening, but also to the expansion in the EVD suspect case definition. Provision of PHC, referral services, and an ambulance network linked EVD response activities to the existing health system and facilitated CBS performance. More importantly, these activities provided a continuum of care that addressed community prioritized health needs. The involvement of local health promotion teams was vital to the CBS and other EVD and PHC activities. Lessons learned include the importance of early and consistent community involvement in surveillance activities and the recommendation to assure local representation in leadership positions.

Community-based COVID-19 active case finding and rapid response in the Democratic Republic of the Congo: Improving case detection and response

A community-based coronavirus disease (COVID-19) active case-finding strategy using an antigen-detecting rapid diagnostic test (Ag-RDT) was implemented in the Democratic Republic of Congo (DRC) to enhance COVID-19 case detection. With this pilot community-based active case finding and response program that was designed as a clinical, prospective testing performance, and implementation study, we aimed to identify insights to improve community diagnosis and rapid response to COVID-19. This pilot study was modeled on the DRC's National COVID-19 Response Plan and the COVID-19 Ag-RDT screening algorithm defined by the World Health Organization (WHO), with case findings implemented in 259 health areas, 39 health zones, and 9 provinces. In each health area, a 7-member interdisciplinary field team tested the close contacts (ring strategy) and applied preventive and control measures to each confirmed case. The COVID-19 testing capacity increased from 0.3 tests per 10,000 inhabitants per week in the first wave to 0.4, 1.6, and 2.2 in the second, third, and fourth waves, respectively. From January to November 2021, this capacity increase contributed to an average of 10.5% of COVID-19 tests in the DRC, with 7,110 positive Ag-RDT results for 40,226 suspected cases and close contacts who were tested (53.6% female, median age: 37 years [interquartile range: 26.0-50.0)]. Overall, 79.7% (n = 32,071) of the participants were symptomatic and 7.6% (n = 3,073) had comorbidities. The Ag-RDT sensitivity and specificity were 55.5% and 99.0%, respectively, based on reverse transcription polymerase chain reaction analysis, and there was substantial agreement between the tests (k = 0.63). Despite its limited sensitivity, the Ag-RDT has improved COVID-19 testing capacity, enabling earlier detection, isolation, and treatment of COVID-19 cases. Our findings support the community testing of suspected cases and asymptomatic close contacts of confirmed cases to reduce disease spread and virus transmission.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Pregnancy in Sub-Saharan Africa: A 6-Country Retrospective Cohort Analysis

BACKGROUND

Few data are available on COVID-19 outcomes among pregnant women in sub-Saharan Africa (SSA), where high-risk comorbidities are prevalent. We investigated the impact of pregnancy on SARS-CoV-2 infection and of SARS-CoV-2 infection on pregnancy to generate evidence for health policy and clinical practice.

METHODS

We conducted a 6-country retrospective cohort study among hospitalized women of childbearing age between 1 March 2020 and 31 March 2021. Exposures were (1) pregnancy and (2) a positive SARS-CoV-2 RT-PCR test. The primary outcome for both analyses was intensive care unit (ICU) admission. Secondary outcomes included supplemental oxygen requirement, mechanical ventilation, adverse birth outcomes, and in-hospital mortality. We used log-binomial regression to estimate the effect between pregnancy and SARS-CoV-2 infection. Factors associated with mortality were evaluated using competing-risk proportional subdistribution hazards models.

RESULTS

Our analyses included 1315 hospitalized women: 510 pregnant women with SARS-CoV-2, 403 nonpregnant women with SARS-CoV-2, and 402 pregnant women without SARS-CoV-2 infection. Among women with SARS-CoV-2 infection, pregnancy was associated with increased risk for ICU admission (adjusted risk ratio [aRR]: 2.38; 95% CI: 1.42-4.01), oxygen supplementation (aRR: 1.86; 95% CI: 1.44-2.42), and hazard of in-hospital death (adjusted sub-hazard ratio [aSHR]: 2.00; 95% CI: 1.08-3.70). Among pregnant women, SARS-CoV-2 infection increased the risk of ICU admission (aRR: 2.0; 95% CI: 1.20-3.35), oxygen supplementation (aRR: 1.57; 95% CI: 1.17-2.11), and hazard of in-hospital death (aSHR: 5.03; 95% CI: 1.79-14.13).

CONCLUSIONS

Among hospitalized women in SSA, both SARS-CoV-2 infection and pregnancy independently increased risks of ICU admission, oxygen supplementation, and death. These data support international recommendations to prioritize COVID-19 vaccination among pregnant women.

The Critical Need for Pooled Data on Coronavirus Disease 2019 in African Children: An AFREhealth Call for Action Through Multicountry Research Collaboration

Globally, there are prevailing knowledge gaps in the epidemiology, clinical manifestations, and outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among children and adolescents; and these gaps are especially wide in African countries. The availability of robust age-disaggregated data is a critical first step in improving knowledge on disease burden and manifestations of coronavirus disease 2019 (COVID-19) among children. Furthermore, it is essential to improve understanding of SARS-CoV-2 interactions with comorbidities and coinfections such as human immunodeficiency virus (HIV), tuberculosis, malaria, sickle cell disease, and malnutrition, which are highly prevalent among children in sub-Saharan Africa. The African Forum for Research and Education in Health (AFREhealth) COVID-19 Research Collaboration on Children and Adolescents is conducting studies across Western, Central, Eastern, and Southern Africa to address existing knowledge gaps. This consortium is expected to generate key evidence to inform clinical practice and public health policy-making for COVID-19 while concurrently addressing other major diseases affecting children in African countries.

Effect of SARS-CoV-2 Infection in Pregnancy on Maternal and Neonatal Outcomes in Africa: An AFREhealth Call for Evidence through Multicountry Research Collaboration

In the African context, there is a paucity of data on SARS-CoV-2 infection and associated COVID-19 in pregnancy. Given the endemicity of infections such as malaria, HIV, and tuberculosis (TB) in sub-Saharan Africa (SSA), it is important to evaluate coinfections with SARS-CoV-2 and their impact on maternal/infant outcomes. Robust research is critically needed to evaluate the effects of the added burden of COVID-19 in pregnancy, to help develop evidence-based policies toward improving maternal and infant outcomes. In this perspective, we briefly review current knowledge on the clinical features of COVID-19 in pregnancy; the risks of preterm birth and cesarean delivery secondary to comorbid severity; the effects of maternal SARS-CoV-2 infection on the fetus/neonate; and in utero mother-to-child SARS-CoV-2 transmission. We further highlight the need to conduct multicountry surveillance as well as retrospective and prospective cohort studies across SSA. This will enable assessments of SARS-CoV-2 burden among pregnant African women and improve the understanding of the spectrum of COVID-19 manifestations in this population, which may be living with or without HIV, TB, and/or other coinfections/comorbidities. In addition, multicountry studies will allow a better understanding of risk factors and outcomes to be compared across countries and subregions. Such an approach will encourage and strengthen much-needed intra-African, south-to-south multidisciplinary and interprofessional research collaborations. The African Forum for Research and Education in Health's COVID-19 Research Working Group has embarked upon such a collaboration across Western, Central, Eastern and Southern Africa.