Mapping the incidence rate of typhoid fever in sub-Saharan Africa.

BACKGROUND: With more than 1.2 million illnesses and 29,000 deaths in sub-Saharan Africa in 2017, typhoid fever continues to be a major public health problem. Effective control of the disease would benefit from an understanding of the subnational geospatial distribution of the disease incidence. METHOD: We collated records of the incidence rate of typhoid fever confirmed by culture of blood in Africa from 2000 to 2022. We estimated the typhoid incidence rate for sub-Saharan Africa on 20 km × 20 km grids by exploring the association with geospatial covariates representing access to improved water and sanitation, health conditions of the population, and environmental conditions. RESULTS: We identified six published articles and one pre-print representing incidence rate estimates in 22 sites in 2000-2022. Estimated incidence rates showed geospatial variation at sub-national, national, and regional levels. The incidence rate was high in Western and Eastern African subregions followed by Southern and Middle African subregions. By age, the incidence rate was highest among 5-14 yo followed by 2-4 yo, > 14 yo, and 0-1 yo. When aggregated across all age classes and grids that comprise each country, predicted incidence rates ranged from 43.7 (95% confidence interval: 0.6 to 591.2) in Zimbabwe to 2,957.8 (95% CI: 20.8 to 4,245.2) in South Sudan per 100,000 person-years. Sub-national heterogeneity was evident with the coefficient of variation at the 20 km × 20 km grid-level ranging from 0.7 to 3.3 and was generally lower in high-incidence countries and widely varying in low-incidence countries. CONCLUSION: Our study provides estimates of 20 km × 20 km incidence rate of typhoid fever across sub-Saharan Africa based on data collected from 2000 through 2020. Increased understanding of the subnational geospatial variation of typhoid fever in Africa may inform more effective intervention programs by better targeting resources to heterogeneously disturbed disease risk.

Characterization of Typhoid Intestinal Perforation in Africa: Results From the Severe Typhoid Fever Surveillance in Africa Program.

Background: Typhoid intestinal perforation (TIP) remains the most serious complication of typhoid fever. In many countries, the diagnosis of TIP relies on intraoperative identification, as blood culture and pathology capacity remain limited. As a result, many cases of TIP may not be reported as typhoid. This study demonstrates the burden of TIP in sites in Burkina Faso, Democratic Republic of Congo (DRC), Ethiopia, Ghana, Madagascar, and Nigeria. Methods: Patients with clinical suspicion of nontraumatic intestinal perforation were enrolled and demographic details, clinical findings, surgical records, blood cultures, tissue biopsies, and peritoneal fluid were collected. Participants were then classified as having confirmed TIP, probable TIP, possible TIP, or clinical intestinal perforation based on surgical descriptions and cultures. Results: A total of 608 participants were investigated for nontraumatic intestinal perforation; 214 (35%) participants had surgically-confirmed TIP and 33 participants (5%) had culture-confirmed typhoid. The overall proportion of blood or surgical site Salmonella enterica subspecies enterica serovar Typhi positivity in surgically verified TIP cases was 10.3%. TIP was high in children aged 5-14 years in DRC, Ghana, and Nigeria. We provide evidence for correlation between monthly case counts of S. Typhi and the occurrence of intestinal perforation. Conclusions: Low S. Typhi culture positivity rates, as well as a lack of blood and tissue culture capability in many regions where typhoid remains endemic, significantly underestimate the true burden of typhoid fever. The occurrence of TIP may indicate underlying typhoid burden, particularly in countries with limited culture capability.

The COVID-19 pandemic and its prolonged impacts on food prices, food consumption and diet quality in sub-Saharan Africa

BackgroundSub-Saharan Africa faces prolonged COVID-19 related impacts on economic activity, livelihoods, nutrition, and food security, with recovery slowed down by lagging vaccination progress. ObjectiveThis study investigated the economic impacts of COVID-19 on food prices, consumption and dietary quality in Burkina Faso, Ethiopia, Ghana, Nigeria, and Tanzania. MethodsWe conducted a repeated cross-sectional study and used a mobile platform to collect data. Data collected from round 1 (July-November, 2020) and round 2 (July-December, 2021) were considered. We assessed participants dietary intake of 20 food groups over the previous seven days. The studys primary outcome was the Prime Diet Quality Score (PDQS), with higher scores indicating better dietary quality. We used linear regression and generalized estimating equations to assess factors associated with diet quality during COVID-19. ResultsMost of the respondents were male and the mean age ({+/-}SD) was 42.4 ({+/-}12.5) years. Mean PDQS ({+/-}SD) was low at 19.1 ({+/-}3.8) before COVID-19, 18.6({+/-}3.4) in Round 1, and 19.4({+/-}3.8) in Round 2. A majority of respondents (80%) reported higher than expected prices for all food groups during the pandemic. Secondary education or higher (estimate: 0.73, 95% CI: 0.32, 1.15), older age (estimate: 30-39 years: 0.77, 95% CI: 0.35, 1.19, or 40 years or older: 0.72, 95% CI: 0.30, 1.13), and medium wealth status (estimate: 0.48, 95% CI: 0.14, 0.81) were associated with higher PDQS. Farmers and casual laborers (estimate: -0.60, 95% CI: -1.11, - 0.09), lower crop production (estimate: -0.87, 95% CI: -1.28, -0.46) and not engaged in farming (estimate: -1.38, 95% CI: -1.74, -1.02) associated with lower PDQS. ConclusionDiet quality which had declined early in the pandemic had started to improve. However, consumption of healthy diets remained low, and food prices remained high. Efforts should continue to improve diet quality for sustained nutrition recovery through mitigation measures, including social protection.

Perceptions and predictors of COVID-19 vaccine hesitancy among health care providers across five countries in sub-Saharan Africa

The African continent has some of the worlds lowest COVID-19 vaccination rates. While the limited availability of vaccines is a contributing factor, COVID-19 vaccine hesitancy among health care providers (HCP) is another factor that could adversely affect efforts to control infections on the continent. We sought to understand the extent of COVID-19 vaccine hesitancy among HCP, and its contributing factors in Africa. We evaluated COVID-19 vaccine hesitancy among 1,499 HCP enrolled in a repeated cross-sectional telephone survey in Burkina Faso, Ethiopia, Nigeria, Tanzania and Ghana. We defined COVID-19 vaccine hesitancy among HCP as self-reported responses of definitely not, maybe, unsure, or undecided on whether to get the COVID-19 vaccine, compared to definitely getting the vaccine. We used Poisson regression models to evaluate factors influencing vaccine hesitancy among HCP. Approximately 65.6% were nurses and the mean age ({+/-}SD) of participants was 35.8 ({+/-}9.7) years. At least 67% of the HCP reported being vaccinated. Reasons for low COVID-19 vaccine uptake included concern about vaccine effectiveness, side effects and fear of receiving unsafe and experimental vaccines. COVID-19 vaccine hesitancy affected 45.7% of the HCP in Burkina Faso, 25.7% in Tanzania, 9.8% in Ethiopia, 9% in Ghana and 8.1% in Nigeria. Respondents reporting that COVID-19 vaccines are very effective (RR:0.21, 95% CI:0.08, 0.55), and older HCP (45 or older vs.20-29 years, RR:0.65, 95% CI: 0.44,0.95) were less likely to be vaccine-hesitant. Nurses were more likely to be vaccine-hesitant (RR 1.38, 95% CI: 1.00,1.89) compared to doctors. We found higher vaccine hesitancy among HCP in Burkina Faso and Tanzania. Information asymmetry among HCP, beliefs about vaccine effectiveness and the endorsement of vaccines by the public health institutions may be important. Efforts to address hesitancy should address information and knowledge gaps among different cadres of HCP and should be coupled with efforts to increase vaccine supply.

Detection of Pathogens of Acute Febrile Illness Using Polymerase Chain Reaction from Dried Blood Spots.

Quantitative polymerase chain reaction (qPCR) of dried blood spots (DBS) for pathogen detection is a potentially convenient method for infectious disease diagnosis. This study tested 115 DBS samples paired with whole blood specimens of children and adolescent from Burkina Faso, Sudan, and Madagascar by qPCR for a wide range of pathogens, including protozoans, helminths, fungi, bacteria, and viruses. Plasmodium spp. was consistently detected from DBS but yielded a mean cycle threshold (Ct) 5.7 ± 1.6 higher than that from whole blood samples. A DBS qPCR Ct cutoff of 27 yielded 94.1% sensitivity and 95.1% specificity against the whole blood qPCR cutoff of 21 that has been previously suggested for malaria diagnosis. For other pathogens investigated, DBS testing yielded a sensitivity of only 8.5% but a specificity of 98.6% compared with whole blood qPCR. In sum, direct PCR of DBS had reasonable performance for Plasmodium but requires further investigation for the other pathogens assessed in this study.

How Can the Typhoid Fever Surveillance in Africa and the Severe Typhoid Fever in Africa Programs Contribute to the Introduction of Typhoid Conjugate Vaccines?

BACKGROUND: The World Health Organization now recommends the use of typhoid conjugate vaccines (TCVs) in typhoid-endemic countries, and Gavi, the Vaccine Alliance, added TCVs into the portfolio of subsidized vaccines. Data from the Severe Typhoid Fever in Africa (SETA) program were used to contribute to TCV introduction decision-making processes, exemplified for Ghana and Madagascar. METHODS: Data collected from both countries were evaluated, and barriers to and benefits of introduction scenarios are discussed. No standardized methodological framework was applied. RESULTS: The Ghanaian healthcare system differs from its Malagasy counterpart: Ghana features a functioning insurance system, antimicrobials are available nationwide, and several sites in Ghana deploy blood culture-based typhoid diagnosis. A higher incidence of antimicrobial-resistant Salmonella Typhi is reported in Ghana, which has not been identified as an issue in Madagascar. The Malagasy people have a low expectation of provided healthcare and experience frequent unavailability of medicines, resulting in limited healthcare-seeking behavior and extended consequences of untreated disease. CONCLUSIONS: For Ghana, high typhoid fever incidence coupled with spatiotemporal heterogeneity was observed. A phased TCV introduction through an initial mass campaign in high-risk areas followed by inclusion into routine national immunizations prior to expansion to other areas of the country can be considered. For Madagascar, a national mass campaign followed by routine introduction would be the introduction scenario of choice as it would protect the population, reduce transmission, and prevent an often-deadly disease in a setting characterized by lack of access to healthcare infrastructure. New, easy-to-use diagnostic tools, potentially including environmental surveillance, should be explored and improved to facilitate identification of high-risk areas.