Effect of booster vaccination against Delta and Omicron variants in Iceland

Norddahl, Gudmundur L.; Melsted, Páll; Gunnarsdóttir, Kristbjörg; Halldorsson, Gisli H.; Gylfason, Arnaldur; Kristjánsson, Már; Magnusson, Olafur T; Sulem, Patrick; Guðbjartsson, Daníel F.; Þorsteinsdóttir, Unnur; Jónsdóttir, Ingileif; Stefánsson, Kāri

doi:10.1101/2022.02.26.22271509

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…Studies have demonstrated that protection conferred by booster vaccination wanes ( 54 – 56 ). Currently, the data necessary to use this approach to evaluate the durability of immunity following booster vaccination are not available to expand our analyses.…”

Section: Discussionmentioning

confidence: 99%

The durability of natural infection and vaccine-induced immunity against future infection by SARS-CoV-2

Townsend

Hassler

Sah

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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The durability of vaccine-mediated immunity to SARS-CoV-2, the durations to breakthrough infection, and the optimal timings of booster vaccination are crucial knowledge for pandemic response. Here, we applied comparative evolutionary analyses to estimate the durability of immunity and the likelihood of breakthrough infections over time following vaccination by BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), ChAdOx1 (Oxford-AstraZeneca), and Ad26.COV2.S (Johnson & Johnson/Janssen). We evaluated anti-Spike (S) immunoglobulin G (IgG) antibody levels elicited by each vaccine relative to natural infection. We estimated typical trajectories of waning and corresponding infection probabilities, providing the distribution of times to breakthrough infection for each vaccine under endemic conditions. Peak antibody levels elicited by messenger RNA (mRNA) vaccines mRNA-1273 and BNT1262b2 exceeded that of natural infection and are expected to typically yield more durable protection against breakthrough infections (median 29.6 mo; 5 to 95% quantiles 10.9 mo to 7.9 y) than natural infection (median 21.5 mo; 5 to 95% quantiles 3.5 mo to 7.1 y). Relative to mRNA-1273 and BNT1262b2, viral vector vaccines ChAdOx1 and Ad26.COV2.S exhibit similar peak anti-S IgG antibody responses to that from natural infection and are projected to yield lower, shorter-term protection against breakthrough infection (median 22.4 mo and 5 to 95% quantiles 4.3 mo to 7.2 y; and median 20.5 mo and 5 to 95% quantiles 2.6 mo to 7.0 y; respectively). These results leverage the tools from evolutionary biology to provide a quantitative basis for otherwise unknown parameters that are fundamental to public health policy decision-making.

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Section: Discussionmentioning

confidence: 99%

The durability of natural infection and vaccine-induced immunity against future infection by SARS-CoV-2

Townsend

Hassler

Sah

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

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“…Following this, Iceland saw a small second wave in August 2020, and a larger third wave of infections in late September through to early November 2020 [ 29 – 31 ]. A fourth wave of COVID-19 cases then hit Iceland in mid-July 2021 dominated by Delta variant infections [ 32 ]. New restrictions were then introduced in November and December 2021 in response to the fifth wave caused by the rapidly spreading Omicron variant [ 32 ].…”

Section: Resultsmentioning

confidence: 99%

“…A fourth wave of COVID-19 cases then hit Iceland in mid-July 2021 dominated by Delta variant infections [ 32 ]. New restrictions were then introduced in November and December 2021 in response to the fifth wave caused by the rapidly spreading Omicron variant [ 32 ].…”

Section: Resultsmentioning

confidence: 99%

Comparing COVID-19 pandemic health responses in two high-income island nations: Iceland and New Zealand

Grout

Gottfreðsson

Kvalsvig

et al. 2023

Scand J Public Health

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Aims: We aimed to compare COVID-19 control measures, epidemiological characteristics and economic performance measures in two high-income island nations with small populations, favorable border control options, and relatively good outcomes: Iceland and New Zealand (NZ). Methods: We examined peer-reviewed journal articles, official websites, reports, media releases and press articles for data on pandemic preparedness and COVID-19 public health responses from 1 January 2020 to 1 June 2022 in Iceland and NZ. We calculated epidemiological characteristics of the COVID-19 pandemic, as well as measures of economic performance. Results: Both nations had the lowest excess mortality in the OECD from the start of the pandemic up to June 2022. Iceland pursued a mitigation strategy, never used lockdowns or officially closed its border to foreign nationals, and instead relied on extensive testing and contact tracing early in the pandemic. Meanwhile, NZ pursued an elimination strategy, used a strict national lockdown to stop transmission, and closed its international border to everyone except citizens and permanent residents going through quarantine and testing. Iceland experienced a larger decrease in gross domestic product in 2020 (relative to 2019) than NZ (–8·27% vs. –1·22%, respectively). In late 2021, NZ announced a shift to a suppression strategy and in 2022 began to reopen its border in stages, while Iceland ended all public restrictions on 25 February 2022. Conclusions: Many of Iceland’s and NZ’s pandemic control measures appeared successful and features of the responses in both countries could potentially be adopted by other jurisdictions to address future disease outbreaks and pandemic threats.

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Comparison of Omicron and Delta Variants of SARS-CoV-2: A Systematic Review of Current Evidence

SeyedAlinaghi,

Afsahi,

Mirzapour

et al. 2024

IDDT

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Introduction: Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) caused the outbreak of coronavirus disease 2019 (COVID-19) in late 2019 in Wuhan, China. In early 2020, the disease spread rapidly around the world. Since the pandemic, SARS-CoV-2 has evolved dramatically into a wide variety of variants endowed with devastating properties. As of March 6, 2022, five SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, Delta, and Omicron strains have been identified. Due to the crucial importance of understanding the differences between the Omicron and Delta variants, this systematic review was conducted. Methods: This systematic review investigated new variants of Omicron SARS-CoV-2 based on cur-rent studies. Online databases were searched for English articles as of January 03, 2023. Selection of publications was a two-step process of title/abstract and full-text assessment against eligibility crite-ria. The relevant data from the included articles were systematically collected and organized in a designed table for analysis. To ensure the quality of the review, the PRISMA checklist and Newcas-tle-Ottawa Scale (NOS) of quality assessment were utilized. Results: The data extracted from 58 articles were analyzed, including 10003 pieces of evidence. Lower risk of hospitalization, ICU admission, and mortality after vaccination were reported in the Omicron variant compared to the Delta variant. Additionally, the Delta variant led to more severe clinical symptoms in comparison to the Omicron variant. Conclusion: The Omicron variant of SARS-CoV-2 results in less severe disease outcomes as com-pared to Delta. Nevertheless, it remains crucial to maintain ongoing monitoring, implement contain-ment measures, and adapt vaccination protocols to effectively address the evolving variants.

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Effect of booster vaccination against Delta and Omicron variants in Iceland

Cited by 4 publications

References 28 publications

The durability of natural infection and vaccine-induced immunity against future infection by SARS-CoV-2

The durability of natural infection and vaccine-induced immunity against future infection by SARS-CoV-2

Comparing COVID-19 pandemic health responses in two high-income island nations: Iceland and New Zealand

Comparison of Omicron and Delta Variants of SARS-CoV-2: A Systematic Review of Current Evidence

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