ABSTRACT
Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massive increase in the number of sequences, exceeding 100,000 genomes generated to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence within their own borders, coupled with a decrease in sequencing turnaround time. Findings from this genomic surveillance underscores the heterogeneous nature of the pandemic but we observe repeated dissemination of SARS-CoV-2 variants within the continent. Sustained investment for genomic surveillance in Africa is needed as the virus continues to evolve, particularly in the low vaccination landscape. These investments are very crucial for preparedness and response for future pathogen outbreaks. One-Sentence SummaryExpanding Africa SARS-CoV-2 sequencing capacity in a fast evolving pandemic.
ABSTRACT
Globally 58.83% human population received at least one dose of the COVID-19 vaccines as of 5 January 2021. COVID-19 vaccination rollout is progressing at varied rates globally and data on the impact of mass vaccination on infection and case-fatality rates require definition. We compared the global reported cumulative case-fatality rate (rCFR) between top-20 countries with COVID-19 vaccination rates (>125 doses/100 people) and the rest of the world, before and after commencement of vaccination programmes. We considered the 28th day of receiving the first vaccine in the world as a cut-off to compare the pre-vaccine period (Jan 1, 2020 - Jan 5, 2021) and the post-vaccine period (Jan 6, 2021-Jan 5, 2022). We used a Generalized linear mixed model (GLMM) with a beta distribution to investigate the association between the CFR and potential predictors of each country and reported the relative risk (RR) of each variable. The mean rCFR of COVID-19 in the top-20 countries with vaccination rates was 1.83 (95% CI: 1.24-2.43) on 5 Jan 2021 and 1.18 (95% CI: 0.73-1.62) on 5 Jan 2022. The CFR for the rest of the world on 5 Jan 2021 was 2.32 (95% CI: 1.86-2.79) and 2.20 (95% CI: 1.86-2.55) on 5 January 2022. In Sub-Saharan Africa, the CFR remained roughly unchanged at 1.97 (95% CI: 1.59-2.35) on 5 Jan 2021 and 1.98 (95% CI:1.58-2.37) on 5 Jan 2022. The GLMM showed vaccination (/100 population) (RR:0.37) and Stringency Index (RR:0.88) were strong protective factors for the countrys COVID-19 CFR indicating that both vaccination and lockdown measures help in the reduction of COVID-19 CFR. The rCFR of COVID-19 continues to decline, although at a disproportionate rate between top vaccinated countries and the rest of the world. Vaccine equity and faster roll-out across the world is critically important in reducing COVID-19 transmission and CFR. Key Questions What is already knownO_LIVaccination can reduce the case-fatality rate of COVID-19. Globally, the COVID-19 vaccination rollout is progressing at varied rates. C_LI What are the new findingsO_LIIn the top-20 countries with vaccination, >200 doses of vaccines are given per 100 people on 5th Jan 2022, In the rest of the word, the figure is 105, and in Sub-Saharan Africa (SSA) only 15.72 C_LIO_LIAfter the introduction of COVID-19 vaccination the reported case-fatality rate (rCFR) of COVID-19 has reduced by 35% in the top-20 countries with vaccination, 8% in the rest of the world roughly unchanged in SSA. C_LIO_LIThe doses of COVID-19 vaccines (/100 people) and rCFR has a negative correlation on 5 Jan 2022 (r=-0.296, p<0.001). C_LIO_LIThe COVID-19 vaccination and Stringency Index are strong protective factors for the countrys COVID-19 rCFR indicating that both vaccination and lockdown measures help in reduction of COVID-19 rCFR. C_LI What do the new findings implyO_LIThe disproportionate case-fatality rate of COVID-19 between top vaccinated countries and the rest of the world demand fast and equitable vaccine rollout globally to reduce COVID-19 transmission and CFR C_LI
ABSTRACT
Objective To explore the possible association between polymorphisms in CD1 genes and both asymptomatic and mild Plasmodium falciparum infection. Methods Two clusters of 85 school children, from the village of Dienga (Gabon) were investigated. The first group was analysed for the prevalence and the multiplicity of asymptomatic P. falciparum infection, whereas the second group was screened for the frequency of malarial attacks. Results Our findings showed that homozygosity for the CD1E*02 allele was associated with a low frequency of malarial attacks. Furthermore, a strong association between CD1E*02 homozygotes and the resistance to multiple malarial attacks was identified. The CD1A*01 allele showed a weak association with a small number of malarial attacks. Conclusion Our results suggest a possible role of CD1E polymorphisms in malaria protection among school children and that CD1e molecules are involved in anti-malarial immunity.
ABSTRACT
OBJECTIVE@#To explore the possible association between polymorphisms in CD1 genes and both asymptomatic and mild Plasmodium falciparum infection.@*METHODS@#Two clusters of 85 school children, from the village of Dienga (Gabon) were investigated. The first group was analysed for the prevalence and the multiplicity of asymptomatic P. falciparum infection, whereas the second group was screened for the frequency of malarial attacks.@*RESULTS@#Our findings showed that homozygosity for the CD1E*02 allele was associated with a low frequency of malarial attacks. Furthermore, a strong association between CD1E*02 homozygotes and the resistance to multiple malarial attacks was identified. The CD1A*01 allele showed a weak association with a small number of malarial attacks.@*CONCLUSION@#Our results suggest a possible role of CD1E polymorphisms in malaria protection among school children and that CD1e molecules are involved in anti-malarial immunity.
ABSTRACT
Malaria in pregnancy remains a serious public health problem in the Republic of Congo despite the implementation of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) in 2006. The aim of this cross-sectional study was to characterize Plasmodium falciparum infections and determine possible risk factors in pregnant Congolese women attending an antenatal clinic in a periurban area of southern Brazzaville. This study was conducted from March 2012 to December 2013 in a site where several years ago, high malaria resistance to SP was reported. Pregnant women were enrolled during antenatal visits and the number of received IPTp-SP doses was recorded as well as individual sociodemographic data. Peripheral blood was collected and P. falciparum infection was checked by microscopy and by PCR targeting P. falciparum merozoite surface protein gene (msp2). Haemoglobin concentration was measured and P. falciparum positive samples were typed for msp2 allelic diversity. A total of 363 pregnant women were recruited. The prevalence of asymptomatic P. falciparum infection was 7% and 19% by microscopy and by PCR, respectively. More than one half (51.5%) of the pregnant women were anaemic. Multivariate analysis indicated that P. falciparum infection was associated with anaemia. It was also observed that women who have received IPTp-SP have significantly lower prevalence of infection. The administration of IPTp-SP did not influence the multiplicity of infection (MOI). This first study investigating asymptomatic malaria infection on pregnant women of the Republic of Congo shows that P. falciparum infections were clearly associated with maternal anaemia, and use of IPTp-SP reduced the risk of carrying asymptomatic infections.
