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.
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.
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.
Although the first year of the COVID-19 pandemic in Africa did not produce the expected catastrophe, the true impact of COVID-19 in the Cameroonian population was unclear. We therefore assessed the seroprevalence of anti-SARS-CoV-2 antibodies and retrospective mortality in a representative sample of the general population in the 10 administrative regions of Cameroon more than one year after the first confirmed cases of COVID-19 in these regions. We aimed to assess the extent of SARS-COV-2 infection and to detect potential increases in the crude mortality rate (CMR) during the SARS-COV-2 pandemic phase.
METHODS
We assessed retrospective mortality and seroprevalence of anti-SARS-CoV-2 antibodies in the 10 capital cities of Cameroon using representative samples of the general population. The study included nested anti-SARS-CoV-2 antibody prevalence surveys and retrospective mortality surveys and was conducted between 27 July 2021 and 31 August 2021. To further analyse crude mortality rates by age group and COVID wave, pre-pandemic and pandemic periods were stratified. Both laboratory-based assays (ELFA) and rapid diagnostic tests (RDT) were used to measure anti-SARS-CoV-2 seroprevalence.
RESULTS
The crude mortality rate (CMR) increased from 0.06 deaths per 10 000 persons per day (pre-pandemic) to 0.17 deaths per 10 000 persons per day (pandemic). The increase in CMR was more pronounced in people aged 20-35 years (pre-pandemic 0.02 deaths per 10 000 persons per day; pandemic 0.06 deaths per 10 000 persons per day). The estimated seroprevalence among unvaccinated persons was 9.5% (RDT) and 15.4% (laboratory-based).
CONCLUSION
The seroprevalence results showed that cases were significantly underdetected by the national surveillance systems.
To describe the implementation of case-area targeted interventions to reduce cholera transmission using a rapid, localized response in Kribi district, Cameroon.
METHODS
We used a cross-sectional design to study the implementation of case-area targeted interventions. We initiated interventions after rapid diagnostic test confirmation of a case of cholera. We targeted households within a 100-250 metre perimeter around the index case (spatial targeting). The interventions package included: health promotion, oral cholera vaccination, antibiotic chemoprophylaxis for nonimmunized direct contacts, point-of-use water treatment and active case-finding.
FINDINGS
We implemented eight targeted intervention packages in four health areas of Kribi between 17 September 2020 and 16 October 2020. We visited 1533 households (range: 7-544 per case-area) hosting 5877 individuals (range: 7-1687 per case-area). The average time from detection of the index case to implementation of interventions was 3.4 days (range: 1-7). Oral cholera vaccination increased overall immunization coverage in Kribi from 49.2% (2771/5621 people) to 79.3% (4456/5621 people). Interventions also led to the detection and prompt management of eight suspected cases of cholera, five of whom had severe dehydration. Stool culture was positive for Vibrio cholerae O1 in four cases. The average time from onset of symptoms to admission of a person with cholera to a health facility was 1.2 days.
CONCLUSION
Despite challenges, we successfully implemented targeted interventions at the tail-end of a cholera epidemic, after which no further cases were reported in Kribi up until week 49 of 2021. The effectiveness of case-area targeted interventions in stopping or reducing cholera transmission needs further investigation.