BACKGROUND

Two sub variants (BA.4 and BA.5) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant are concerning as they are spreading rapidly worldwide; however, no published data concerning these variants are available in Cameroon. We report the early detection of these new sub variants that are associated with the onset of the fifth wave of coronavirus 2019 (COVID-19) in Cameroon.

METHODS

Positive samples were selected for next-generation sequencing (NGS). BA.4 and BA.5 complete genome sequences underwent sequence data analysis, epidemiology analysis of COVID-19’s resurgence and wave, recombination and pairwise matrix analysis, and phylogenetic analysis. We selected the first nine SARS-CoV-2 Omicron BA.4 and BA.5 sub variants detected in Cameroon using local whole genome sequencing for the NGS analysis.

RESULTS

During the fifth wave of resurgence of COVID-19 cases in Cameroon, it was found that the Northwest and Littoral regions were the most affected areas, while the Center and Littoral regions recorded the highest number of new deaths. The study identified evidence of recombination between the BA.2 sub variant and BA.4 and BA.5 Cameroonian strains. This result highlights the dynamic nature of SARS-CoV-2 evolution. The BA.5 strain (entitled hCoV-19/Cameroon/23850/2022) showed the highest sequence similarity to the first reported genome of the Omicron strain with 497 mutations. Phylogenetic analysis revealed that these nine Omicron sub variants were grouped into a distinct and highly distant cluster separate from the first Omicron variant detected in Botswana and were intermixed with sequences from other countries (the United States, Denmark, Scotland, and England), thus implying multiple introductions of the BA.4 and BA.5 sub variants in Cameroon.

CONCLUSIONS

Omicron BA.4 and BA.5 sub-lineages are associated with the onset of the fifth wave of COVID-19 in Cameroon. In addition to providing early warning of COVID-19 resurgence, continuous local genome sequencing of emerging variants is essential for detecting variants of concern, thereby guiding the country's response. This study emphasizes the value of real-time surveillance.

Snakes responsible for bites are rarely identified, resulting in a loss of information about snakebites from venomous species whose venom effects are poorly understood. A prospective clinical study including patients bitten by a snake was conducted in Cameroon between 2019 and 2021 to evaluate the efficacy and tolerability of a marketed polyvalent antivenom. Clinical presentation during the first 3 days of hospitalization was recorded following a standardized protocol. This ancillary study aimed to assess the frequency of bites by the different species encountered in Cameroon and to describe the symptoms of bites by formally identified species. Of the 447 patients included in the study, 159 (35.6%) brought the snake that caused the bite that was identified by a specialist. Out of these, 8 specimens could not be identified due to poor condition, 19 were non-venomous species, and 95 belonged to Echis romani—formerly E. ocellatus—species. The remaining 37 specimens included 2 Atheris squamigera, 12 Atractaspis spp., 2 Bitis arietans, 11 Causus maculatus, 1 Dendroaspis jamesoni, 1 Naja haje, 1 N. katiensis, 5 N. melanoleuca complex, and 2 N. nigricollis. Symptoms, severity of envenomation, and post-treatment course are described. Symptoms and severity of bites are consistent with cases described in the literature, but some specific features are highlighted.

BACKGROUND

Little is known about the evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity in African communities.

AIM

We evaluated changes in anti-SARS-CoV-2 antibodies, mortality and vaccination status in Cameroon between August 2021 and September 2022 to begin describing the evolution of the pandemic in Africa.

SETTING

The study was conducted across Cameroon’s 10 regional capitals, between 2021 and 2022 as the country hosted a mass gathering.

METHODS

We conducted a cross-sectional population-based survey in 2022, including SARS-CoV-2 seroprevalence testing and retrospective mortality estimation using two-stage cluster sampling. We estimated and compared seroprevalence and crude mortality rates (CMR) to a survey conducted in 2021 using the same methodology.

RESULTS

We performed serologic testing on 8400 individuals and collected mortality data from 22 314 individuals. Approximately 5% in each survey reported SARS-CoV-2-vaccination. Rapid diagnostic test-based seroprevalence increased from 11.2% (95% confidence interval [CI]: 10–12.5) to 59.8% (95% CI: 58.3–61.2) between 2021 and 2022, despite no increase in the proportion vaccinated. The CMR decreased from 0.17 to 0.06 deaths per 10 000 persons per day between 2021 and 2022. In 2022, no deaths were reportedly attributable to COVID-19 as compared to 17 deaths in 2021.

CONCLUSION

Over a 12-month period encompassing two waves of omicron variant SARS-CoV-2 and a mass gathering, SARS-CoV-2 seropositivity in Cameroon approached 60%, and deaths declined despite low vaccination coverage.

CONTRIBUTION

This study challenges the assumption that high immunisation coverage is the sole determinant of epidemic control in the African context and encourages policymakers to increasingly rely on local research when designing response strategies for more effective outbreak management.

OBJECTIVES

Chest x‐ray (CXR) plays an important role in childhood tuberculosis (TB) diagnosis, but access to quality CXR remains a major challenge in resource‐limited settings. Digital CXR (d‐CXR) can solve some image quality issues and facilitate their transfer for quality control. We assess the implementation of introducing d‐CXR in 12 district hospitals (DHs) in 2021–2022 across Cambodia, Cameroon, Ivory Coast, Mozambique, Sierra Leone and Uganda as part of the TB‐speed decentralisation study on childhood TB diagnosis.

METHODS

For digitisation of CXR, digital radiography (DR) plates were setup on existing analogue radiography devices. d‐CXR were transferred to an international server at Bordeaux University and downloaded by sites' clinicians for interpretation. We assessed the uptake and performance of CXR services and health care workers' (HCW) perceptions of d‐CXR implementation. We used a convergent mixed method approach utilising process data, individual interviews with 113 HCWs involved in performing or interpreting d‐CXRs and site support supervision reports.

RESULTS

Of 3104 children with presumptive TB, 1642 (52.9%) had at least one d‐CXR, including 1505, 136 and 1 children with one, two and three d‐CXRs, respectively, resulting in a total of 1780 d‐CXR. Of them, 1773 (99.6%) were of good quality and 1772/1773 (99.9%) were interpreted by sites' clinicians. One hundred and sixty‐four children had no d‐CXR performed despite attending the radiography department: 126, 37 and 1 with one, two and three attempts, respectively. d‐CXRs were not performed in 21.6% (44/203) due to connectivity problem between the DR plate captor and the computer. HCW reported good perceptions of d‐CXR and of the DR plates provided. The main challenge was the upload to and download from the server of d‐CXRs due to limited internet access.

CONCLUSION

d‐CXR using DR plates was feasible at DH level and provided good quality images but required overcoming operational challenges.

Current malaria diagnostics are invasive, lack sensitivity, and rapid tests are plagued by deletions in target antigens. Here we introduce the Cytophone, an innovative photoacoustic flow cytometer platform with high-pulse-rate lasers and a focused ultrasound transducer array to noninvasively detect and identify malaria-infected red blood cells (iRBCs) using specific wave shapes, widths, and time delays generated from the absorbance of laser energy by hemozoin, a universal biomarker of malaria infection. In a population of Cameroonian adults with uncomplicated malaria, we assess our device for safety in a cross-sectional cohort (n = 10) and conduct a performance assessment in a longitudinal cohort (n = 20) followed for 30 ± 7 days after clearance of parasitemia. Longitudinal cytophone measurements are compared to point-of-care and molecular assays (n = 94). Cytophone is safe with 90% sensitivity, 69% specificity, and a receiver-operator-curve-area-under-the-curve (ROC-AUC) of 0.84, as compared to microscopy. ROC-AUCs of Cytophone, microscopy, and RDT compared to quantitative PCR are not statistically different from one another. The ability to noninvasively detect iRBCs in the bloodstream is a major advancement which offers the potential to rapidly identify both the large asymptomatic reservoir of infection, as well as diagnose symptomatic cases without the need for a blood sample.

BACKGROUND

Little is known about attitudes towards COVID-19 vaccination in sub-Saharan Africa, where immunisation coverage is the lowest in the world.

AIM

The study aimed to identify factors associated with COVID-19 vaccine hesitancy and uptake in Cameroon, and assess changes in these factors over a period of time.

SETTING

The study was conducted in the ten regions of Cameroon.

METHODS

The authors conducted a two-phase cross-sectional survey in the 10 regions of Cameroon, from July 2021 to August 2021 (Phase one) and from August 2022 to September 2022 (Phase two). We analysed reasons for vaccine hesitancy descriptively and used logistic regression to assess factors associated with hesitancy.

RESULTS

Overall, we enrolled 12 109 participants: 6567 (54.23%) in Phase one and 5542 (45.77%) in Phase two. Of these, 8009 (66.14%) were not interested in receiving the COVID-19 vaccine (n = 4176 in Phase one, n = 3833 in Phase two). The refusal rate increased significantly in the northern region from 27.00% in Phase 1 to 60.00% in Phase two. The leading contributor to COVID-19 vaccine hesitancy was fear that the vaccine was dangerous, which was significantly associated (95% confidence interval [CI], p < 0.05%) with vaccine refusal in both phases. Overall, 32.90% of participants (n = 2578) perceived the COVID-19 vaccine to be dangerous. Advanced age, male gender, Muslim religion and low level of education were associated with vaccine acceptance. Participants reported that healthcare workers were the most trusted source of information about the COVID-19 vaccine by 5005 (42.84%) participants.

CONCLUSION

Despite the investment of the Ministry of Health and its partners in community engagement, focussing on communication about the vaccine efficacy, tolerance and potential adverse events, fear of the vaccine remains high, likely leading to vaccine hesitancy in Cameroon between 2021 and 2022.

CONTRIBUTION

The study highlight regional variations in COVID-19 vaccine acceptance in Cameroon, with factors age, gender, religion and education influencing willingness to vaccine. Trust in health workers was high, indicating that, tailored, community-led vaccination strategies are key for improving vaccine uptake, not only for COVID-19 but also for future epidemics.