ABSTRACT
SARS-CoV-2 was first detected in Sudan on 13th March 2020. Here, we describe the genomic epidemiology of SARS-CoV-2 in Sudan between May 2020 and April 2022 to understand the introduction and transmission of SARS-CoV-2 variants in the country. A total of 667 SARS-CoV-2 positive samples were successfully sequenced using the nCoV-19 Artic protocol on the Oxford Nanopore Technology ([≥]70% genome completeness). The genomes were compared with a select contemporaneous global dataset to determine genetic relatedness and estimate import/export events. The genomes were classified into 37 Pango lineages within the ancestral strain (107 isolates across 13 Pango lineages), Eta variant of interest (VOI) (78 isolates in 1 lineage), Alpha variant of concern (VOC) (10 isolates in 2 lineages), Beta VOC (26 isolates in 1 lineage), Delta VOC (171 isolates across 8 lineages) and Omicron VOC (242 isolates across 12 lineages). We estimated a total of 144 introductions of the observed variants from different countries across the globe. Multiple introductions of the Eta VOI, Beta VOC and Omicron VOC were observed in Sudan mainly from Europe and Africa. These findings suggest a need for continuous genomic surveillance of SARS-CoV-2 to monitor their introduction and spread consequently inform public health measures to combat SARS-CoV-2 transmission.
ABSTRACT
Abstract Background The non-pharmaceutical interventions (NPIs) implemented to curb the spread of SARS_CoV_2 early in the COVID_19 pandemic years, disrupted the activity of other respiratory viruses. There is limited data from low and middle income countries (LMICs) to determine whether COVID_19 NPIs also impacted the epidemiology of enteric viruses. We investigated the changes in infection patterns of common enteric viruses among hospitalised children who presented with diarrhoea to a referral hospital in coastal Kenya, in the period spanning the COVID_19 pandemic. Methods A total of 870 stool samples from children under 13 years of age admitted to Kilifi County Hospital between January 2019, and December 2022 were screened for rotavirus group A (RVA), norovirus genogroup II (GII), astrovirus, sapovirus, and adenovirus type F40/41 using realtime reverse transcription polymerase chain reaction. The proportions positive across the four years were compared using the chi-squared test statistic. Results One or more of the five virus targets were detected in 282 (32.4%) cases. A reduction in the positivity rate of RVA cases was observed from 2019 (12.1%, 95% confidence interval (CI) 8.7% to 16.2%) to 2020 (1.7%, 95% CI 0.2% to 6.0%; p < 0.001). However, in the 2022, RVA positivity rate rebounded to 23.5% (95% CI 18.2% to 29.4%). For norovirus GII, the positivity rate fluctuated over the four years with its highest positivity rate observed in 2020 (16.2%; 95% C.I, 10.0% to 24.1%). No astrovirus cases were detected in 2020 and 2021, but the positivity rate in 2022 was similar to that in 2019 (3.1% (95% CI 1.5% to 5.7%) vs 3.3% (95% CI 1.4% to 6.5%)). A higher case fatality rate was observed in 2021 (9.0%) compared to the 2019 (3.2%), 2020 (6.8%) and 2022 (2.1%) (p <0.001). Conclusion Our study finds that in 2020 the transmission of common enteric viruses, especially RVA and astrovirus, in Kilifi Kenya may have been disrupted due to the COVID_19 NPIs. After 2020, local enteric virus transmission patterns appeared to return to prepandemic levels coinciding with the removal of most of the government COVID_19 NPIs.
Subject(s)
COVID-19 , DiarrheaABSTRACT
Background Analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomic sequence data from household infections should aid its detailed epidemiological understanding. Using viral genomic sequence data, we investigated household SARS-CoV-2 transmission and evolution in coastal Kenya households. Methods We conducted a case-ascertained cohort study between December 2020 and February 2022 whereby 573 members of 158 households were prospectively monitored for SARS-CoV-2 infection. Households were invited to participate if a member tested SARS-CoV-2 positive or was a contact of a confirmed case. Follow-up visits collected a nasopharyngeal/oropharyngeal (NP/OP) swab on days 1, 4 and 7 for RT-PCR diagnosis. If any of these were positive, further swabs were collected on days 10, 14, 21 and 28. Positive samples with an RT-PCR cycle threshold of <33.0 were subjected to whole genome sequencing followed by phylogenetic analysis. Ancestral state reconstruction was used to determine if multiple viruses had entered households. Results Of 2,091 NP/OP swabs that were collected, 375 (17.9%) tested SARS-CoV-2 positive. Viral genome sequences (>80% coverage) were obtained from 208 (55%) positive samples obtained from 61 study households. These genomes fell within 11 Pango lineages and four variants of concern (Alpha, Beta, Delta and Omicron). We estimated 163 putative transmission events involving members of the sequenced households, 40 (25%) of which were intra-household transmission events while 123 (75%) were infections that likely occurred outside the households. Multiple virus introductions (up-to-5) were observed in 28 (47%) households with the 1-month follow-up period. Conclusions We show that a considerable proportion of SARS-CoV-2 infections in coastal Kenya occurred outside the household setting. Multiple virus introductions frequently occurred into households within the same infection wave in contrast to observations from high income settings, where single introduction appears to be the norm. Our findings suggests that control of SARS-CoV-2 transmission by household member isolation may be impractical in this setting.
Subject(s)
Coronavirus Infections , Severe Acute Respiratory Syndrome , COVID-19ABSTRACT
The emergence and establishment of SARS CoV 2 variants of concern presented a major global public health crisis across the world. There were six waves of SARS CoV 2 cases in Kenya that corresponded with the introduction and eventual dominance of the major SARS-COV-2 variants of concern, excepting the first 2 waves that were both wildtype virus. We estimate that more than 1000 SARS CoV 2 introductions occurred in the two-year epidemic period (March 2020 to September 2022) and a total of 930 introductions were associated with variants of concern namely Beta (n=78), Alpha(n=108), Delta(n=239) and Omicron (n=505). A total of 29 introductions were associated with A.23.1 variant that circulated in high frequencies in Uganda and Rwanda. The actual number of introductions is likely to be higher than these conservative estimates due to limited genomic sequencing. Our data suggested that cryptic transmission was usually underway prior to the first real-time identification of a new variant, and that multiple introductions were responsible. Following emergence of each VOC and subsequent introduction, transmission patterns were associated with hotspots of transmission in Coast, Nairobi and Western Kenya and follows established land and air transport corridors. Understanding the introduction and dispersal of major circulating variants and identifying the sources of new introductions is important to inform public health control strategies within Kenya and the larger East-African region. Border control and case finding reactive to new variants is unlikely to be a successful control strategy.