SARS-CoV-2 Delta VOC in Scotland: demographics, risk of hospital admission, and vaccine effectiveness

Sheikh, Aziz; McMenamin, Jim; Taylor, Bob; Robertson, Chris

doi:10.1016/s0140-6736(21)01358-1

Cited by 939 publications

(818 citation statements)

References 6 publications

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“…Collectively, these mutations increase viral transmissibility and alter the neutralizing ability of monoclonal antibodies and convalescent plasma from recovered patients with COVID-19. A recent study published in the journal Lancet suggested that the risk of hospitalization doubled in those infected with the Delta variant of SARS-CoV-2 as compared to the Alpha variant (11). Additionally, this study also underscored the protective effect of vaccination against infection with this variant.…”

supporting

confidence: 56%

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An Evolving Public Health Crisis Caused by the Rapid Spread of the SARS-CoV-2 Delta Variant

Rao

Singh²

2021

DHRP

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supporting

confidence: 56%

“…Two doses of the AstraZeneca vaccine were 60% effective against symptomatic disease from the B.1.617.2 variant. It is notable that both vaccines were only 33% effective against symptomatic disease from Delta variant, three weeks after the first dose (11).…”

mentioning

confidence: 99%

An Evolving Public Health Crisis Caused by the Rapid Spread of the SARS-CoV-2 Delta Variant

Rao

Singh²

2021

DHRP

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“…1 Few studies have reported the effectiveness of COVID-19 vaccines against infection or severe outcomes caused by VOCs. [2][3][4][5] All four VOCs, Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2), have been circulating at various times in Canada, where a delayed second-dose strategy was implemented due to vaccine supply constraints.…”

mentioning

confidence: 99%

Effectiveness of mRNA and ChAdOx1 COVID-19 vaccines against symptomatic SARS-CoV-2 infection and severe outcomes with variants of concern in Ontario

Nasreen

Chung

et al. 2021

Preprint

129

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Objectives: To estimate the effectiveness of BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and ChAdOx1 (AstraZeneca) vaccines against symptomatic SARS-CoV-2 infection and severe outcomes (COVID-19 hospitalization or death) caused by the Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) variants of concern (VOCs) during December 2020 to May 2021. Methods: We conducted a test-negative design study using linked population-wide vaccination, laboratory testing, and health administrative databases in Ontario, Canada. Results: Against symptomatic infection caused by Alpha, vaccine effectiveness with partial vaccination (≥14 days after dose 1) was higher for mRNA-1273 than BNT162b2 and ChAdOx1. Full vaccination (≥7 days after dose 2) increased vaccine effectiveness for BNT162b2 and mRNA-1273 against Alpha. Protection against symptomatic infection caused by Beta/Gamma was lower with partial vaccination for ChAdOx1 than mRNA-1273. Against Delta, vaccine effectiveness after partial vaccination tended to be lower than against Alpha for BNT162b2 and mRNA-1273, but was similar to Alpha for ChAdOx1. Full vaccination with BNT162b2 increased protection against Delta to levels comparable to Alpha and Beta/Gamma. Vaccine effectiveness against hospitalization or death caused by all studied VOCs was generally higher than for symptomatic infection after partial vaccination with all three vaccines. Conclusions: Our findings suggest that even a single dose of these 3 vaccine products provide good to excellent protection against symptomatic infection and severe outcomes caused by the 4 currently circulating variants of concern, and that 2 doses are likely to provide even higher protection.

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“…There have been several alarms raised that the Delta variant could become dominant if people did not complete the full COVID-19 vaccination. 16,17 In a recent study conducted in Scotland, the first dose was shown not to confer complete immunity against the Delta variant than the Alpha variant, however, full vaccination (two-doses) improves immune effectiveness. 16 Our present study confirms that in the postvaccine rollout in Canada (i.e., December 2020), vaccination coverage rates are uneven across the country.…”

Section: Discussionmentioning

confidence: 99%

“…16,17 In a recent study conducted in Scotland, the first dose was shown not to confer complete immunity against the Delta variant than the Alpha variant, however, full vaccination (two-doses) improves immune effectiveness. 16 Our present study confirms that in the postvaccine rollout in Canada (i.e., December 2020), vaccination coverage rates are uneven across the country. While Northwest Territories and Yukon had fully vaccinated more than half of their residents, Newfoundland and Labrador and Nova Scotia had only vaccinated 6% of their residents.…”

Section: Discussionmentioning

confidence: 99%

Implications of COVID-19 vaccination and public health countermeasures on SARS-CoV-2 variants of concern in Canada: evidence from a spatial hierarchical cluster analysis

Marks

et al. 2021

Preprint

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Background: The influence of coronavirus disease-2019 (COVID-19) containment measures on variants of concern (VOC) has been understudied in Canada. Our objective was to identify provinces with disproportionate prevalence of VOC relative to COVID-19 mitigation efforts in provinces and territories in Canada. Methods: We analyzed publicly available provincial- and territorial-level data on the prevalence of VOCs in relation to mitigating factors (summarized in three measures: 1. strength of public health countermeasures: stringency index, 2. how much people moved about outside their homes: mobility index, and 3. vaccine intervention: proportion of Canadian population fully vaccinated). Using spatial agglomerative hierarchical cluster analysis (unsupervised machine learning), the provinces and territories were grouped into clusters by stringency index, mobility index and full vaccine coverage. Kruskal-Wallis test was used to determine the differences in the prevalence of VOC (Alpha, or B.1.1.7, Beta, or B.1.351, Gamma, or P.1, and Delta, or B.1.617.2 variants) between the clusters. Results: Three clusters of vaccine uptake and countermeasures were identified. Cluster 1 consisted of the three Canadian territories, and characterized by higher degree of vaccine deployment and lesser degree of countermeasures. Cluster 2 (located in Central Canada and Atlantic region) was typified by lesser implementation of vaccine deployment and moderate countermeasures. The third cluster was formed by provinces inthe Pacific region, Central Canada, and Prairie region, with moderate vaccine deployment but stronger countermeasures. The overall and variant-specific prevalence were significantly different across the clusters. Interpretation: This study found that implementation of COVID-19 public health measures varied across the provinces and territories. Considering the high prevalence of VOCs in Canada, completing the second dose of COVID-19 vaccine in a timely manner is crucial.

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SARS-CoV-2 Delta VOC in Scotland: demographics, risk of hospital admission, and vaccine effectiveness

Cited by 939 publications

References 6 publications

An Evolving Public Health Crisis Caused by the Rapid Spread of the SARS-CoV-2 Delta Variant

An Evolving Public Health Crisis Caused by the Rapid Spread of the SARS-CoV-2 Delta Variant

Effectiveness of mRNA and ChAdOx1 COVID-19 vaccines against symptomatic SARS-CoV-2 infection and severe outcomes with variants of concern in Ontario

Implications of COVID-19 vaccination and public health countermeasures on SARS-CoV-2 variants of concern in Canada: evidence from a spatial hierarchical cluster analysis

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