Analysis of contact tracing data showed contribution of asymptomatic and non-severe infections to the maintenance of SARS-CoV-2 transmission in Senegal.

During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission clusters, their analysis allowed to understand their dynamics and evolution. In this study, we used information from the surveillance data and phone interviews to construct, represent and analyze COVID-19 transmission clusters from March 2, 2020, to May 31, 2021. In total, 114,040 samples were tested and 2153 transmission clusters identified. A maximum of 7 generations of secondary infections were noted. Clusters had an average of 29.58 members and 7.63 infected among them; their average duration was 27.95 days. Most of the clusters (77.3%) are concentrated in Dakar, capital city of Senegal. The 29 cases identified as super-spreaders, i.e., the indexes that had the most positive contacts, showed few symptoms or were asymptomatic. Deepest transmission clusters are those with the highest percentage of asymptomatic members. The correlation between proportion of asymptomatic and degree of transmission clusters showed that asymptomatic strongly contributed to the continuity of transmission within clusters. During this pandemic, all the efforts towards epidemiological investigations, active case-contact detection, allowed to identify in a short delay growing clusters and help response teams to mitigate the spread of the disease.

Unintended consequences of implementing non-pharmaceutical interventions for the COVID-19 response in Africa: experiences from DRC, Nigeria, Senegal, and Uganda.

INTRODUCTION: The coronavirus (COVID 19) pandemic is one of the most terrifying disasters of the twenty-first century. The non-pharmaceutical interventions (NPIs) implemented to control the spread of the disease had numerous positive consequences. However, there were also unintended consequences-positively or negatively related to the nature of the interventions, the target, the level and duration of implementation. This article describes the unintended economic, Psychosocial and environmental consequences of NPIs in four African countries. METHODS: We conducted a mixed-methods study in the Democratic Republic of Congo (DRC), Nigeria, Senegal and Uganda. A comprehensive conceptual framework, supported by a clear theory of change was adopted to encompass both systemic and non-systemic interventions. The data collection approaches included: (i) review of literature; (ii) analysis of secondary data for selected indicators; and (ii) key informant interviews with policy makers, civil society, local leaders, and law enforcement staff. The results were synthesized around thematic areas. RESULTS: Over the first six to nine months of the pandemic, NPIs especially lockdowns, travel restrictions, curfews, school closures, and prohibition of mass gathering resulted into both positive and negative unintended consequences cutting across economic, psychological, and environmental platforms. DRC, Nigeria, and Uganda observed reduced crime rates and road traffic accidents, while Uganda also reported reduced air pollution. In addition, hygiene practices have improved through health promotion measures that have been promoted for the response to the pandemic. All countries experienced economic slowdown, job losses heavily impacting women and poor households, increased sexual and gender-based violence, teenage pregnancies, and early marriages, increased poor mental health conditions, increased waste generation with poor disposal, among others. CONCLUSION: Despite achieving pandemic control, the stringent NPIs had several negative and few positive unintended consequences. Governments need to balance the negative and positive consequences of NPIs by anticipating and instituting measures that will support and protect vulnerable groups especially the poor, the elderly, women, and children. Noticeable efforts, including measures to avoid forced into marriage, increasing inequities, economic support to urban poor; those living with disabilities, migrant workers, and refugees, had been conducted to mitigate the negative effects of the NIPs.

Epidemiology of Non-SARS-CoV2 Human Coronaviruses (HCoVs) in People Presenting with Influenza-like Illness (ILI) or Severe Acute Respiratory Infections (SARI) in Senegal from 2012 to 2020.

In addition to emerging coronaviruses (SARS-CoV, MERS, SARS-CoV-2), there are seasonal human coronaviruses (HCoVs): HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1. With a wide distribution around the world, HCoVs are usually associated with mild respiratory disease. In the elderly, young children and immunocompromised patients, more severe or even fatal respiratory infections may be observed. In Africa, data on seasonal HCoV are scarce. This retrospective study investigated the epidemiology and genetic diversity of seasonal HCoVs during nine consecutive years of influenza-like illness surveillance in Senegal. Nasopharyngeal swabs were collected from ILI outpatients or from SARI hospitalized patients. HCoVs were diagnosed by qRT-PCR and the positive samples were selected for molecular characterization. Among 9337 samples tested for HCoV, 406 (4.3%) were positive: 235 (57.9%) OC43, 102 (25.1%) NL63, 58 (14.3%) 229E and 17 (4.2%) HKU1. The four types circulated during the study period and a peak was noted between November and January. Children under five were the most affected. Co-infections were observed between HCoV types (1.2%) or with other viruses (76.1%). Genetically, HCoVs types showed diversity. The results highlighted that the impact of HCoVs must be taken into account in public health; monitoring them is therefore particularly necessary both in the most sensitive populations and in animals.

Acceptability of contact management and care of simple cases of COVID-19 at home: a cross-sectional study in Senegal.

BACKGROUND: COVID-19 is a major public health problem. In mid-2020, due to the health system challenges from increased COVID-19 cases, the Ministry of Health and Social Action in Senegal opted for contact management and care of simple cases at home. The objective of the study was to determine the acceptability of contact and simple case management of COVID-19 at home and its associated factors in Senegal. METHODS: This was a descriptive and analytical cross-sectional study. We collected data from 11 June to 10 July 2020. We used a marginal quota sampling strategy. A total of 813 individuals took part in the survey. We collected data using a telephone interview. RESULTS: The care of simple cases of COVID-19 at home was well accepted (78.5%). The use of home contact management was less accepted (51.4%). Knowledge of the modes of transmission of the virus and confidence in institutional information were associated with the acceptability of home care for simple cases. Regularly searching for information on COVID-19 and confidence in the government's control of the epidemic were associated with the acceptability of managing contacts at home. CONCLUSIONS: Authorities should take these factors into account for better communication to improve the acceptability and confidence in home-based care for COVID-19 and future epidemics.

Time trends in infectious and chronic disease consultations in Dakar, Senegal: Impact of COVID-19 sanitary measures.

Background: The impact of COVID-19 sanitary measures on the time trends in infectious and chronic disease consultations in Sub-Saharan Africa remains unknown. Methods: We conducted a cohort study on all emergency medical consultations from January 2016 to July 2020, from SOS Medecins in Dakar, Senegal. The consultation records provided basic demographic information such as age, ethnicity (Senegalese or Caucasian), and sex as well as the principal diagnosis using an ICD-10 classification ("infectious", "chronic", and "other"). We first investigated how the pattern in emergency consultation differed from March to July 2020 compared to previous years. Then, we examined any potential racial/ethnic disparities in COVID-19 consultation. Results: We obtained data on emergency medical consultations from 53 583 patients of all ethnic origins. The mean age of patients was 37.0 (standard deviation (SD) = 25.2) and 30.3 (SD = 21.7) in 2016-2019 and 45.5 (SD = 24.7) and 39.5 (SD = 23.3) in 2020 for Senegalese and Caucasian patients, respectively. The type of consultations between January and July were similar from 2016 to 2019; however, in 2020, there was a drop in the number of infectious disease consultations, particularly from April to May 2020, when sanitary measures for COVID-19 were applied (average of 366.5 and 358.2 in 2016-1019 and 133.0 and 125.0 in 2020). The prevalence of chronic conditions remained steady during the same period (average of 381.0 and 394.7 in 2016-2019 and 373.0 and 367.0 in 2020). In a multivariate analysis adjusted for age and sex, infectious disease consultations were significantly more likely to occur in 2016-2019 compared to 2020 (2016 odds ratio (OR) = 2.39, 2017 OR = 2.74, 2018 OR = 2.39, 2019 OR = 2.01). Furthermore, the trend in the number of infectious and chronic consultations was similar among Senegalese and Caucasian groups, indicating no disparities among those seeking treatment. Conclusions: During the implementation of COVID-19 sanitary measures, infectious disease rates dropped as chronic disease rates remained stagnant in Dakar. We observed no racial/ethnic disparities among the infectious and chronic consultations.

[Epidemiology and response strategies against COVID-19: the Senegalese experience from 2020 to 2021]. / Epidémiologie et stratégies de riposte contre la COVID-19: l´expérience sénégalaise de 2020 à 2021.

Introduction: in response to the SARS-CoV-2 pandemic that reached Senegal in March 2020, the country has put in place several strategies to contain its spread. The purpose of this study was to describe the epidemiology and the strategies adopted. Méthods: we conducted a descriptive cross-sectional study of confirmed cases of COVID-19 using RT-PCR test in Senegal from March 2, 2020 to September 30, 2021. Data were collected through a literature review and analyzed with R and QGIS software. Proportions and means with standard deviation were calculated. Results: Senegal has recorded a total of 73,782 confirmed cases and 1,859 deaths from SARS-CoV-2. The temporal evolution was marked by three epidemic waves. The epidemic was concentrated in high-density areas such as Dakar (48,656 cases or 66%), in men (sex-ratio 1:13) and in the age group 25-34 years (16.527 cases or 22.4%). The average age of patients was 43 ± 18 years; the national cumulative incidence was 428 per 100,000 population and the overall case fatality rate was 2.5% (1,859/73,782). Some strategies have been implemented, including staff training, restrictive measures, home-based case management and vaccination. Nine point two percent (840,154/9,128,453) of the target population received 2 doses of vaccine. Conclusion: the epidemic was spread more widely within some population groups. We recommend strengthening preventive measures in high-density cities and mobilizing community networks to encourage immunization.

Spread and seasonality of COVID-19 pandemic confirmed cases in sub-Saharan Africa: experience from Democratic Republic of Congo, Nigeria, Senegal, and Uganda.

BACKGROUND: The COVID-19 pandemic has impacted the world negatively with huge health and socioeconomic consequences. This study estimated the seasonality, trajectory, and projection of COVID-19 cases to understand the dynamics of the disease spread and inform response interventions. METHOD: Descriptive analysis of daily confirmed COVID-19 cases from January 2020 to 12th March 2022 was conducted in four purposefully selected sub-Saharan African countries (Nigeria, Democratic Republic of Congo (DRC), Senegal, and Uganda). We extrapolated the COVID-19 data from (2020 to 2022) to 2023 using a trigonometric time series model. A decomposition time series method was used to examine the seasonality in the data. RESULTS: Nigeria had the highest rate of spread (ß) of COVID-19 (ß = 381.2) while DRC had the least rate (ß = 119.4). DRC, Uganda, and Senegal had a similar pattern of COVID-19 spread from the onset through December 2020. The average doubling time in COVID-19 case count was highest in Uganda (148 days) and least in Nigeria (83 days). A seasonal variation was found in the COVID-19 data for all four countries but the timing of the cases showed some variations across countries. More cases are expected in the 1st (January-March) and 3rd (July-September) quarters of the year in Nigeria and Senegal, and in the 2nd (April-June) and 3rd (October-December) quarters in DRC and Uganda. CONCLUSION: Our findings show a seasonality that may warrant consideration for COVID-19 periodic interventions in the peak seasons in the preparedness and response strategies.

First wave COVID-19 pandemic in Senegal: Epidemiological and clinical characteristics.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) pandemic has spread from China to the rest of the world. Africa seems less impacted with lower number of cases and deaths than other continents. Senegal recorded its first case on March 2, 2020. We present here data collected from March 2 to October 31, 2020 in Senegal. METHODS: Socio-demographic, epidemiological, clinical and virological information were collected on suspected cases. To determine factors associated with diagnosed infection, symptomatic disease and death, multivariable binary logistic regression and log binomial models were used. Epidemiological parameters such as the reproduction number and growth rate were estimated. RESULTS: 67,608 suspected cases were tested by the IPD laboratories (13,031 positive and 54,577 negative). All age categories were associated with SARS-CoV-2 infection, but also patients having diabetes or hypertension or other cardiovascular diseases. With diagnosed infection, patients over 65 years and those with hypertension and cardiovascular disease and diabetes were highly associated with death. Patients with co-morbidities were associated with symptomatic disease, but only the under 15 years were not associated with. Among infected, 27.67% were asymptomatic (40.9% when contacts were systematically tested; 12.11% when only symptomatic or high-risk contacts were tested). Less than 15 years-old were mostly asymptomatic (63.2%). Dakar accounted for 81.4% of confirmed cases. The estimated mean serial interval was 5.57 (± 5.14) days. The average reproduction number was estimated at 1.161 (95%CI: 1.159-1.162), the growth rate was 0.031 (95%CI: 0.028-0.034) per day. CONCLUSIONS: Our findings indicated that factors associated with symptomatic COVID-19 and death are advanced age (over 65 years-old) and comorbidities such as diabetes and hypertension and cardiovascular disease.

Hepatitis E Virus Seroprevalence and Associated Risk Factors in Pregnant Women Attending Antenatal Consultations in Senegal.

In West Africa, research on the hepatitis E virus (HEV) is barely covered, despite the recorded outbreaks. The low level of access to safe water and adequate sanitation is still one of the main factors of HEV spread in developing countries. HEV infection induces acute or sub-clinical liver diseases with a mortality rate ranging from 0.5 to 4%. The mortality rate is more alarming (15 to 25%) among pregnant women, especially in the last trimester of pregnancy. Herein, we conducted a multicentric socio-demographic and seroepidemiological survey of HEV in Senegal among pregnant women. A consecutive and non-redundant recruitment of participants was carried out over the period of 5 months, from March to July 2021. A total of 1227 consenting participants attending antenatal clinics responded to a standard questionnaire. Plasma samples were collected and tested for anti-HEV IgM and IgG by using the WANTAI HEV-IgM and IgG ELISA assay. The overall HEV seroprevalence was 7.8% (n = 96), with 0.5% (n = 6) and 7.4% (n = 91) for HEV IgM and HEV IgG, respectively. One of the participant samples was IgM/IgG-positive, while four were declared indeterminate to anti-HEV IgM as per the manufacturer's instructions. From one locality to another, the seroprevalence of HEV antibodies varied from 0 to 1% for HEV IgM and from 1.5 to 10.5% for HEV IgG. The data also showed that seroprevalence varied significantly by marital status (p < 0.0001), by the regularity of income (p = 0.0043), and by access to sanitation services (p = 0.0006). These data could serve as a basis to setup national prevention strategies focused on socio-cultural, environmental, and behavioral aspects for a better management of HEV infection in Senegal.

Connaissances, attitudes et pratiques de la population de la région de Dakar sur la COVID-19.

INTRODUCTION: Faced with the increase in confirmed cases of COVID-19 in Senegal, particularly in the region of Dakar, epicenter of the disease, it is necessary to study the knowledge, attitudes and practices of the populations of the West and South districts on COVID-19. METHODS: A cross-sectional and analytical study was conducted from May 9 to 30, 2020. A four-stage cluster survey was carried out at the level of the West and South districts. Univariate and multivariate analyzes were carried out using R 3.4.4 software. RESULTS: In total, 400 people were surveyed. The mean age of those surveyed was 40.2 ± 14.7 years and extremes of 18 and 82 years. The male sex predominated in 66.5% of cases. People had good knowledge of the signs, transmission risks and prevention measures respectively in 4.7%; 3% and 47.8%. In total, 74% of the people surveyed respected the concept of "stay at home". Wearing a mask and systematic hand washing with soap and water were noted among the people surveyed in 53.6% and 34.8% of cases, respectively. People who had good knowledge of preventive measures against COVID-19 wore the mask more (ORaj = 2.1 [1.2-3.5]) and washed their hands more with soap and water (ORaj = 1.9 [1.1-3.4]). CONCLUSION: For an effective fight against this epidemic, it is important to strengthen risk communication with full community participation. This strategy must be coupled with actions aimed at making prevention means available to the benefit of the entire population.

Private sector engagement in the COVID-19 response: experiences and lessons from the Democratic Republic of Congo, Nigeria, Senegal and Uganda.

BACKGROUND: Private entities play a major role in health globally. However, their contribution has not been fully optimized to strengthen delivery of public health services. The COVID-19 pandemic has overwhelmed health systems and precipitated coalitions between public and private sectors to address critical gaps in the response. We conducted a study to document the public and private sector partnerships and engagements to inform current and future responses to public health emergencies. METHODS: This was a multi-country cross-sectional study conducted in the Democratic Republic of Congo, Nigeria, Senegal and Uganda between November 2020 and March 2021 to assess responses to the COVID-19 pandemic. We conducted a scoping literature review and key informant interviews (KIIs) with private and public health sector stakeholders. The literature reviewed included COVID-19 country guidelines and response plans, program reports and peer-reviewed and non-peer-reviewed publications. KIIs elicited information on country approaches and response strategies specifically the engagement of the private sector in any of the strategic response operations. RESULTS: Across the 4 countries, private sector strengthened laboratory systems, COVID-19 case management, risk communication and health service continuity. In the DRC and Nigeria, private entities supported contact tracing and surveillance activities. Across the 4 countries, the private sector supported expansion of access to COVID-19 testing services through establishing partnerships with the public health sector albeit at unregulated fees. In Senegal and Uganda, governments established partnerships with private sector to manufacture COVID-19 rapid diagnostic tests. The private sector also contributed to treatment and management of COVID-19 cases. In addition, private entities provided personal protective equipment, conducted risk communication to promote adherence to safety procedures and health promotion for health service continuity. However, there were concerns related to reporting, quality and cost of services, calling for quality and price regulation in the provision of services. CONCLUSIONS: The private sector contributed to the COVID-19 response through engagement in COVID-19 surveillance and testing, management of COVID-19 cases, and health promotion to maintain health access. There is a need to develop regulatory frameworks for sustainable public-private engagements including regulation of pricing, quality assurance and alignment with national plans and priorities during response to epidemics.

Cross-sectional study of COVID-19 knowledge, beliefs and prevention behaviours among adults in Senegal.

OBJECTIVES: The aim of the study was to explore COVID-19 beliefs and prevention behaviours in a francophone West African nation, Senegal. DESIGN: This was a cross-sectional analysis of survey data collected via a multimodal observational study. PARTICIPANTS: Senegalese adults aged 18 years or older (n=1452). PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome measures were COVID-19 prevention behaviours. Secondary outcome measures included COVID-19 knowledge and beliefs. Univariate, bivariate and multivariate statistics were generated to describe the sample and explore potential correlations. SETTING: Participants from Senegal were recruited online and telephonically between June and August 2020. RESULTS: Mask wearing, hand washing and use of hand sanitiser were most frequently reported. Social distancing and staying at home were also reported although to a lower degree. Knowledge and perceived risk of COVID-19 were very high in general, but risk was a stronger and more influential predictor of COVID-19 prevention behaviours. Men, compared with women, had lower odds (adjusted OR (aOR)=0.59, 95% CI 0.46 to 0.75, p<0.001) of reporting prevention behaviours. Rural residents (vs urban; aOR=1.49, 95% CI 1.12 to 1.98, p=0.001) and participants with at least a high school education (vs less than high school education; aOR=1.33, 95% CI 1.01 to 1.76, p=0.006) were more likely to report COVID-19 prevention behaviours. CONCLUSIONS: In Senegal, we observed high compliance with recommended COVID-19 prevention behaviours among our sample of respondents, in particular for masking and personal hygiene practice. We also identified a range of psychosocial and demographic predictors for COVID-19 prevention behaviours such as knowledge and perceived risk. Stakeholders and decision makers in Senegal and across Africa can use place-based evidence like ours to address COVID-19 risk factors and intervene effectively with policies and programming. Use of both phone and online surveys enhances representation and study generalisability and should be considered in future research with hard-to-reach populations.

Surveillance of Viral Encephalitis in the Context of COVID-19: A One-Year Observational Study among Hospitalized Patients in Dakar, Senegal.

The burden of encephalitis and its associated viral etiology is poorly described in Africa. Moreover, neurological manifestations of COVID-19 are increasingly reported in many countries, but less so in Africa. Our prospective study aimed to characterize the main viral etiologies of patients hospitalized for encephalitis in two hospitals in Dakar. From January to December 2021, all adult patients that met the inclusion criteria for clinical infectious encephalitis were enrolled. Cerebrospinal fluids, blood, and nasopharyngeal swabs were taken and tested for 27 viruses. During the study period, 122 patients were enrolled. Viral etiology was confirmed or probable in 27 patients (22.1%), with SARS-CoV-2 (n = 8), HSV-1 (n = 7), HHV-7 (n = 5), and EBV (n = 4) being the most detected viruses. Age groups 40-49 was more likely to be positive for at least one virus with an odds ratio of 7.7. The mortality was high among infected patients, with 11 (41%) deaths notified during hospitalization. Interestingly, SARS-CoV-2 was the most prevalent virus in hospitalized patients presenting with encephalitis. Our results reveal the crucial need to establish a country-wide surveillance of encephalitis in Senegal to estimate the burden of this disease in our population and implement strategies to improve care and reduce mortality.

Did COVID-19 Impact Contraceptive Uptake? Evidence from Senegal.

This study assessed the impact of the COVID-19 pandemic on the number of new contraceptive acceptors in Senegal overall and by method. Monthly service data from March 2019 to December 2020 were extracted for the number of new contraceptive users of IUDs, implants, injectables, and oral contraceptive pills (OCPs). Data were analyzed using descriptive statistics and interrupted time series analysis for trend analyses overall and by the contraceptive method. Following the announcement of the first COVID-19 case in Senegal in March 2020, there was an immediate significant decrease in the number of new acceptors overall, and for new users of implants and injectables. From March-December 2020, the trend in monthly new family planning acceptors increased overall, mainly driven by significant increases in new IUD and implant acceptors. Compared to the period before the onset of COVID-19, there was a statistically significant shift from shorter-acting methods (OCPs, injectables) to long-acting reversible methods (IUDs, implants). Despite the immediate adverse impact of COVID-19-related restrictions, the number of new acceptors rebounded, trends in the number of new monthly acceptors significantly increased, and there was a significant shift to longer-acting methods.

Demographics and outcomes of laboratory-confirmed COVID-19 cases during the first epidemic wave in Senegal.

BACKGROUND: Few studies have focused on the effects of COVID-19 on African populations. During the first epidemic wave in Senegal (May 1 to July 31, 2020), COVID-19 cases were isolated in treatment centers of epidemics (TCEs). We described the demographics and outcomes of COVID-19 cases in TCEs. PATIENTS AND METHODS: All cases with laboratory-confirmed COVID-19 in Thiès medical region of Senegal were included. RESULTS: COVID-19 was confirmed in 600 cases. Median age of cases (men: 357, 59.5%; women: 243, 40.5%) was 34.0years. The incidence was 12 per 100,000 inhabitants per month. Overall, 46 (7.7%) cases had a severe or critical form of the disease, and nine of them died. Of 455 cases quarantined in non-hospital TCEs, 340 (74.7%) had no symptom and 115 (25.3%) had mild or moderate symptoms. CONCLUSION: In this African retrospective cohort, COVID-19 cases were young and mostly asymptomatic with a low case fatality rate.

Factors associated with the acceptability of government measures to address COVID-19 in Senegal.

INTRODUCTION: Three months after the first appearance of the new coronavirus (COVID-19), Senegal recorded its first case on March 2, 2020. Faced with this pandemic, the State reacted quickly with public measures : instituting a curfew, placing a ban on travel between regions, and closing shops and places of worship. This research aims to study the acceptability of these non-pharmaceutical measures by the Senegalese population. METHOD: This study was a cross-sectional and analytical survey conducted in June and July 2020 among Senegalese over 18 years old. Sampling by the representative quota method was distributed proportionally to age, gender and region. We constructed the questionnaire using the theoretical framework of acceptability of health interventions. Through a telephone call center synchronised to an internet server, we collected data on personal characteristics, knowledge of the disease, trust in information sources, trust in government, concern about the pandemic, and the seven dimensions of acceptability. We performed descriptive analysis and structural equation with R software version 4.0.2. RESULTS: This study included a total of 813 individuals. The average age was 34.7 years ( ± 14.2 years). They were predominantly male (54.6 %), with no education (42.6 %). The increased level of knowledge of the disease was associated with confidence in national media information sources provided by the administrative and health authorities (ß=0.11, p<0.01). The increase in the level of trust in the government in response to COVID-19 was positively related to the acceptability of curfew (ß=0.16, p<0.001), travel ban between regions (ß=0.11, p<0.001), and closure of places of worship (ß=0.1, p<0.01) and markets (ß=0.09, p<0.01). CONCLUSION: In Senegal, the acceptability of the measures depended on knowledge of the disease, perception of the risk of the disease, and trust in the government. There is a need to strengthen awareness and risk communication of COVID-19.

Tropicalisation of epidemiological models in Africa: A mixed and hybrid approach to better predict COVID-19 indicators.

CONTEXT: Since the outbreak of the SARS-COV2 epidemic turned into a COVID-19 pandemic, international bodies such as the WHO as well as governments have announced projections for morbidity and mortality indicators related to COVID-19. Most of them indicated that the health situation would be worrying. Although using artificial intelligence with mathematical algorithms and/or neural networks, the results of the SIR models were poorly performing and not very accurate in relation to the observed reality in the African states in general and in Senegal in particular. Hence the imperative need to configure the modelling process and approach considering local contexts. METHOD: The model implemented is a mixed prediction model based on the Bucky model developed by OCHA and adapted to the context. The construction of the mixed model was done in two steps (basic model with publicly available data, such as those from United Nations-like organisations such as OCHA or WHO for Senegal), (adding more specific data collected through the mixed epidemiological survey). This survey was conducted in Senegal in six localities (Dakar, Thies, Diourbel, Kedougou, Saint-Louis and Ziguinchor) chosen according to the number of confirmed cases of COVID-19. In total, 1000 individuals distributed in proportion to the size of the regions were interviewed in April 2021. RESULTS: The projected cases in the baseline model were already considerably higher than the cases reported in April. This may be plausible, given the low detection rates throughout Senegal during this period. However, the hybrid model predicted an even higher infection rate than the baseline, perhaps mainly due to vulnerability related to food insecurity and solid cooking fuels. This may mean that there would be more unreported cases than reported. Overall, the mortality rate of both models would be considerably lower than the government-reported mortality rate, even though the number of confirmed cases remains high. This may be an underestimate of the death rate. CONCLUSION: An accurate and reliable prediction in times of epidemics and/or pandemics, such as COVID-19, should be based on mixed or hybrid data integrating a quantitative and qualitative approach to enable better policymaking. The projections resulting from this approach would still be effective and would take better account of local realities and contexts, especially for developing countries.

Non-pharmaceutical interventions and COVID-19 vaccination strategies in Senegal: a modelling study.

BACKGROUND: When vaccines against the novel COVID-19 were available in Senegal, many questions were raised. How long should non-pharmaceutical interventions (NPIs) be maintained during vaccination roll-out? What are the best vaccination strategies? METHODS: In this study, we used an age-structured dynamic mathematical model. This model uses parameters based on SARS-CoV-2 virus, information on different types of NPIs, epidemiological and demographic data, some parameters relating to hospitalisations and vaccination in Senegal. RESULTS: In all scenarios explored, the model predicts a larger third epidemic wave of COVID-19 in terms of new cases and deaths than the previous waves. In a context of limited vaccine supply, vaccination alone will not be sufficient to control the epidemic, and the continuation of NPIs is necessary to flatten the epidemic curve. Assuming 20% of the population have been vaccinated, the optimal period to relax NPIs would be a few days from the last peak. Regarding the prioritisation of age groups to be vaccinated, the model shows that it is better to vaccinate individuals aged 5-60 years and not just the elderly (over 60 years) and those in high-risk groups. This strategy could be more cost-effective for the government, as it would reduce the high costs associated with hospitalisation. In terms of vaccine distribution, the optimal strategy would be to allocate full dose to the elderly. If vaccine doses are limited, half dose followed by full dose would be sufficient for people under 40 years because whether they receive half or full dose, the reduction in hospitalisations would be similar and their death-to-case ratio is very low. CONCLUSIONS: This study could be presented as a decision support tool to help devise strategies to control the COVID-19 pandemic and help the Ministry of Health to better manage and allocate the available vaccine doses.

Prevalence of SARS-CoV-2 antibodies in hemodialysis patients in Senegal: a multicenter cross-sectional study.

BACKGROUND: Hemodialysis patients are among high-risk groups for COVID-19. Africa is the continent with the lowest number of cases in the general population but we have little information about the disease burden in dialysis patients. OBJECTIVES: This study aimed to describe the seroprevalence of SARS-CoV-2 antibodies in the hemodialysis population of Senegal. PATIENTS AND METHODS: We conducted a multicenter cross-sectional survey, between June and September 2020 involving 10 public dialysis units randomly selected in eight regions of Senegal. After seeking their consent, we included 303 patients aged ≥ 18 years and hemodialysis for ≥ 3 months. Clinical symptoms and biological parameters were collected from medical records. Patients' blood samples were tested with Abbott SARS-CoV-2 Ig G assay using an Architect system. Statistical tests were performed with STATA 12.0. RESULTS: Seroprevalence of SARS-CoV-2 antibodies was 21.1% (95% CI = 16.7-26.1%). We noticed a wide variability in SARS-CoV-2 seroprevalence between regions ranging from 5.6 to 51.7%. Among the 38 patients who underwent nasal swab testing, only six had a PCR-confirmed infection and all of them did seroconvert. Suggestive clinical symptoms were reported by 28.1% of seropositive patients and the majority of them presented asymptomatic disease. After multivariate analysis, a previous contact with a confirmed case and living in a high population density region were associated with the presence of SARS-CoV-2 antibodies. CONCLUSION: This study presents to our knowledge the first seroprevalence data in African hemodialysis patients. Compared to data from other continents, we found a higher proportion of patients with SARS-CoV-2 antibodies but a lower lethality rate.