Impact of cross-border-associated cases on the SARS-CoV-2 epidemic in Switzerland during summer 2020 and 2021.

During the summers of 2020 and 2021, the number of confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Switzerland remained at relatively low levels, but grew steadily over time. It remains unclear to what extent epidemic growth during these periods was a result of the relaxation of local control measures or increased traveling and subsequent importation of cases. A better understanding of the role of cross-border-associated cases (imports) on the local epidemic dynamics will help to inform future surveillance strategies. We analyzed routine surveillance data of confirmed cases of SARS-CoV-2 in Switzerland from 1 June to 30 September 2020 and 2021. We used a stochastic branching process model that accounts for superspreading of SARS-CoV-2 to simulate epidemic trajectories in absence and in presence of imports during summer 2020 and 2021. The Swiss Federal Office of Public Health reported 22,919 and 145,840 confirmed cases of SARS-CoV-2 from 1 June to 30 September 2020 and 2021, respectively. Among cases with known place of exposure, 27% (3,276 of 12,088) and 25% (1,110 of 4,368) reported an exposure abroad in 2020 and 2021, respectively. Without considering the impact of imported cases, the steady growth of confirmed cases during summer periods would be consistent with a value of Re that is significantly above the critical threshold of 1. In contrast, we estimated Re at 0.84 (95% credible interval, CrI: 0.78-0.90) in 2020 and 0.82 (95% CrI: 0.74-0.90) in 2021 when imported cases were taken into account, indicating that the local Re was below the critical threshold of 1 during summer. In Switzerland, cross-border-associated SARS-CoV-2 cases had a considerable impact on the local transmission dynamics and can explain the steady growth of the epidemic during the summers of 2020 and 2021.

Availability and experiences of differentiated antiretroviral therapy delivery at HIV care facilities in rural Zimbabwe: a mixed-method study.

INTRODUCTION: Zimbabwe adopted differentiated HIV care policies in 2015 to promote client-centred care and relieve strain on health facilities. We examined the availability, experiences and perceptions of differentiated antiretroviral therapy (ART) delivery in rural Zimbabwe following the policy adoption. METHODS: We undertook a cross-sectional mixed methods study in all the 26 facilities providing HIV care in a rural district in Zimbabwe. We collected quantitative data about ART delivery and visit durations from 31 healthcare providers and a purposive stratified sample of 378 clients obtaining ART either through routine care or differentiated ART delivery models. We performed 26 semi-structured interviews among healthcare providers and seven focus group discussions (FGDs) among clients to elicit their perceptions and experiences of ART delivery. Data were collected in 2019, with one follow-up FGD in 2021. We analysed the transcripts thematically, with inductive coding, to identify emerging themes. RESULTS: Twenty facilities (77%) offered at least one differentiated ART delivery models, including community ART refill groups (CARGs; 13 facilities, 50%), fast-track refill (8, 31%), family refill (6, 23%) or club refill (1, 4%). Thirteen facilities (50%) offered only one model. The median visit duration was 28 minutes (interquartile range [IQR]: 16-62). Participants in fast-track had the shortest visit durations (18 minutes, IQR: 11-24). Confidentiality and disclosure of HIV status, travelling long distances, travel costs and waiting times were the main issues influencing clients' views on differentiated ART delivery. Fast-track refill was perceived as the preferred model of clients for its limited involuntary disclosure and efficiency. In contrast, group- and community-based refill models reduced travel costs but were felt to be associated with involuntary disclosure of HIV status, which could discourage clients. Healthcare providers also experienced an additional workload when offering facility-based group models, such as CARGs. CONCLUSIONS: Differentiated ART delivery models were widely available in this rural setting, but most facilities did not offer a choice of models to address clients' diverse preferences. A minority offered fast-track refills, although this model was often mentioned as desirable. Confidentiality, travel expenses and client waiting times are key elements to consider when planning and rolling out differentiated HIV care.

Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3-5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant's success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes.

Emergence and spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

Following its emergence in late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic resulting in unprecedented efforts to reduce transmission and develop therapies and vaccines (WHO Emergency Committee, 2020; Zhu et al., 2020). Rapidly generated viral genome sequences have allowed the spread of the virus to be tracked via phylogenetic analysis (Worobey et al., 2020; Hadfield et al., 2018; Pybus et al., 2020). While the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced, allowing continent-specific variants to emerge. However, within Europe travel resumed in the summer of 2020, and the impact of this travel on the epidemic is not well understood. Here we report on a novel SARS-CoV-2 variant, 20E (EU1), that emerged in Spain in early summer, and subsequently spread to multiple locations in Europe. We find no evidence of increased transmissibility of this variant, but instead demonstrate how rising incidence in Spain, resumption of travel across Europe, and lack of effective screening and containment may explain the variant's success. Despite travel restrictions and quarantine requirements, we estimate 20E (EU1) was introduced hundreds of times to countries across Europe by summertime travellers, likely undermining local efforts to keep SARS-CoV-2 cases low. Our results demonstrate how a variant can rapidly become dominant even in absence of a substantial transmission advantage in favorable epidemiological settings. Genomic surveillance is critical to understanding how travel can impact SARS-CoV-2 transmission, and thus for informing future containment strategies as travel resumes.