Profile of Serological (IgM/IgG) and Virological Markers of COVID-19 in Some Private Universities in Cameroon During the Pandemic (preprint)

Background: COVID-19 remains a rapidly evolving and deadly pandemic worldwide. This necessitates the continuous assessment of existing diagnostic tools for robust, up-to-date and cost-effective pandemic response strategy. We sought to determine the infection rate (PCR-positivity) and degree of spread (IgM/IgG) of SARS-CoV-2 in three university settings in Cameroon Method: Study volunteers were recruited from November 2020 to July 2021 among COVID-19 non-vaccinated students in three Universities from two regions of Cameroon (West and Centre). Molecular testing was performed by RT-qPCR on nasopharyngeal swabs and IgM/IgG antibodies in plasma were detected using the Abbott Panbio IgM/IgG rapid diagnostic test (RDT) at the Virology Laboratory of CREMER/IMPM/MINRESI. The molecular and serological profiles were compared and, p<0.05 considered statistically significant. Results: Amongst the 291 participants enrolled (mean age 22.59±10.43 years), 19.59% (57/291) were symptomatic and 80.41 %(234/2691) asymptomatic. Overall COVID-19 PCR-positivity rate was 21.31% (62/291), distributed as follows: 25.25% from UdM-Bangangte; 27.27% from ISSBA-Yaounde and 5% from IUEs/INSAM-Yaounde. Women were more affected than men (28.76% [44/153] vs. 13.04% [18/138], p<0.0007) and they significantly expressed more IgM+/IgG+ (15.69% [24/153] vs. 7.25% [10/138], p<0.01). Participants from Bangangté, the nomadic, and the “non-contact cases” mainly presented an active infection compared to those from Yaoundé (p= 0.05; p=0.05 and p=0.01 respectively). Overall IgG seropositivity (IgM-/IgG+ and IgM+/IgG+) was 24.4% (71/291). A proportion of 26.92% (7/26) presenting COVID-19 IgM+/IgG- had negative PCR versus 73.08% (19/26) with positive PCR, p<0.0001. Furthermore, 17.65% (6/34) with COVID-19 IgM+/IgG+ had negative PCR as compared to 82.35% positive PCR (28/34), p<0.0001. Lastly, 7.22% (14/194) with IgM-/IgG- had a positive PCR. Conclusion: This study calls for a rapid preparedness and response strategy in higher institutes in case of any future pathogen with pandemic or epidemic potentials. The observed disparity between IgG/IgM and viral profile supports prioritizing assays targeting the virus (nucleic acid or antigen) for diagnosis and antibody screening for sero-surveys

Clinical presentation of COVID-19 at the time of testing and factors associated with pre-symptomatic cases in Cameroon.

Objectives: To describe the clinical features at time of testing and explore factors associated with SARS-CoV-2 infection and pre-symptomatic cases in Cameroon. Methods: Data was collected on people in Cameroon who participated in COVID-19 testing by real-time reverse transcriptase-polymerase chain reaction between 1 March and 5 October 2020. After descriptive analysis, multivariate logistic regression was used to identify factors associated with SARS-CoV-2 infection and pre-symptomatic cases. Results: Of 85 206 test participants, 14 863 (17.4%) were infected with SARS-CoV-2. The median age for cases was 38.4 years (interquartile range 29.6-49.4); 6.1% were aged <19 years, and 6.3% were ≥65 years. Of these cases, 46.5% had at least one symptom/sign with a median time from illness onset to testing of 6 days (interquartile range 3-9). Cough (64.2%), headache (46.5%), fatigue/malaise (46.0%), shortness of breath (30.6%) and myalgia/arthralgia (25.6%) were the most commonly observed symptoms/signs. Pre-symptomatic SARS-CoV-2 infection was associated with age <50 years, being male and absence of comorbidities. Conclusion: This study provides a comprehensive summary of the early clinical profile of SARS-CoV-2 infection during the first wave of COVID-19 in Cameroon, which was dominated by pre-symptomatic illness. These findings would be helpful for SARS-CoV-2 surveillance and control at a regional level.

SARS-CoV-2 antibody seroprevalence and associated risk factors in an urban district of Cameroon (preprint)

The extent of SARS-CoV-2 circulation in many African countries remains unclear, underlining the need for antibody sero-surveys to assess the cumulative attack rate. Here, we present the results of a cross-sectional sero-survey of a random sample of residents of a health district in Yaoundé, Cameroon, conducted from October 14 to November 26, 2020. Among the 971 participants, the test-adjusted seroprevalence of anti-SARS-CoV-2 IgG antibodies was 29·2% (95%CI 24·3–34·1). This is about 323 times greater than the 0.09% nationwide attack rate implied by COVID-19 case counts at the time. Men, obese individuals and those living in large households were significantly more likely to be seropositive, and the majority (64·2% [58·7–69·4]) of seropositive individuals reported no symptoms. Despite the high seroprevalence, most of the population had not been infected with SARS-CoV-2, highlighting the importance of continued measures to control viral spread and quick vaccine deployment to protect the vulnerable.

SARS-CoV-2 Antibody Seroprevalence and Associated Risk Factors in an Urban District in Cameroon (preprint)

Background: The extent of SARS-CoV-2 circulation in many African countries remains unclear, underscoring the need for antibody sero-surveys to accurately assess the cumulative attack rate. Methods: We conducted a community-based, cross-sectional sero-survey in Cité Verte, a densely-populated district of Yaoundé, Cameroon, from October 14 to November 26, 2020. Households were randomly selected from a set of all putative residential buildings in the district, and residents between five and 80 years of age were surveyed. The Abbott Panbio SARS-CoV-2 nucleocapsid IgM/IgG rapid antibody test was administered, along with a questionnaire on disease symptoms and health-seeking behavior. Final seroprevalence estimates were adjusted for test accuracy and re-weighted to the city’s age-sex distribution. Random-intercept logistic regression was used to identify risk factors for anti-SARS-CoV-2 IgG seropositivity. Findings: Of 255 households randomly selected, 180 (70·6%) agreed to participate, yielding a sample of 971 participants. The adjusted seroprevalence of SARS-CoV-2 IgG antibodies was 29·2% (95%CI 24·3–34·1). Out of the 302 IgG seropositive individuals, the majority (64·2% [58·7–69·4]) did not report any symptoms over the pandemic period, and most (91·1% [87·3–93·8]) did not consult medical care. Significantly greater odds of IgG seropositivity was found for men (OR: 1·61 [95%CI 1·2–2·2]), residents of households with six or more residents (OR: 1·6 [1·1–2·4]; reference: households with three to five residents) and individuals with a BMI above 30 kg/m² (OR: 1·84 [1·1–3·0]; reference: 18·5–24.9 kg/m²).  Interpretation: By November 2020, the cumulative attack rate of COVID-19 was high in this Cameroonian city, about 323 times greater than the 0.09% nationwide attack rate implied by PCR and antigen- confirmed case counts at the time. The predominantly asymptomatic nature of cases may explain the low COVID-19-related healthcare consultation. Despite the high seroprevalence, most of the population has not been infected with SARS-CoV-2, underlining the importance of continued measures to control viral spread and of quick vaccine deployment to protect the vulnerable. Funding: The UHC Program and Bilateral Health Project in Cameroon of the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, the P4H Health Financing Network, and the Canton of Geneva. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The study protocol obtained the ethical clearance (N°2020/09/1292/CE/CNERSH/SP) and the administrative authorization of the Ministry of Health of Cameroon (N°D30- 845/L/MINSANTE/SG/DROS).