Optimizing vaccine allocation for COVID-19 vaccines shows the potential role of single-dose vaccination

Matrajt, Laura; Eaton, Julia; Leung, Tiffany; Dimitrov, Dobromir; Schiffer, Joshua T.; Swan, David A.; Janes, Holly

doi:10.1038/s41467-021-23761-1

Cited by 116 publications

(123 citation statements)

References 38 publications

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“…The optimal order of prioritization will depend upon the measure being optimized (i.e. protecting essential societal functions or directly minimizing health harms, such as cases, hospitalizations or deaths, or some combination of these) [10][11][12]. In the UK, vaccination policy advice is provided by the Joint Committee on Vaccination and Immunization (JCVI).…”

Section: Introductionmentioning

confidence: 99%

Vaccine escape in a heterogeneous population: insights for SARS-CoV-2 from a simple model

et al. 2021

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As a countermeasure to the SARS-CoV-2 pandemic, there has been swift development and clinical trial assessment of candidate vaccines, with subsequent deployment as part of mass vaccination campaigns. However, the SARS-CoV-2 virus has demonstrated the ability to mutate and develop variants, which can modify epidemiological properties and potentially also the effectiveness of vaccines. The widespread deployment of highly effective vaccines may rapidly exert selection pressure on the SARS-CoV-2 virus directed towards mutations that escape the vaccine-induced immune response. This is particularly concerning while infection is widespread. By developing and analysing a mathematical model of two population groupings with differing vulnerability and contact rates, we explore the impact of the deployment of vaccines among the population on the reproduction ratio, cases, disease abundance and vaccine escape pressure. The results from this model illustrate two insights: (i) vaccination aimed at reducing prevalence could be more effective at reducing disease than directly vaccinating the vulnerable; (ii) the highest risk for vaccine escape can occur at intermediate levels of vaccination. This work demonstrates a key principle: the careful targeting of vaccines towards particular population groups could reduce disease as much as possible while limiting the risk of vaccine escape.

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Section: Introductionmentioning

confidence: 99%

Vaccine escape in a heterogeneous population: insights for SARS-CoV-2 from a simple model

et al. 2021

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“…The baseline values of vaccine efficacy used in the model are listed in Table 1 . The overall vaccine effectiveness against disease (denoted by VE ) was modeled as a function of the risk of infection and risk of symptomatic disease, conditional to infection [ 27 ]. Specifically, the vaccine effectiveness (

) against strain j ( j = 1 for wild-type and j = 2 for SARS-CoV-2 variant) among age group k is represented as

where

represents vaccine efficacy against infection and

represents the efficacy against symptomatic disease, conditional to infection.…”

Section: Methodsmentioning

confidence: 99%

Projecting the Impact of SARS-CoV-2 Variants and the Vaccination Program on the Fourth Wave of the COVID-19 Pandemic in South Korea

Shim

2021

IJERPH

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Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are currently administered in South Korea; however, vaccine supply is limited. Considering constraints in vaccine supply and the emergence of variant strains, we evaluated the impact of coronavirus disease (COVID-19) vaccination program in reducing incidence, ICU hospitalization, and deaths in South Korea. We developed an age-structured model of SARS-CoV-2 transmission parameterized with Korean demographics and age-specific COVID-19 outcomes. Using our model, we analyzed the impact of the COVID-19 vaccination program during the fourth wave of the pandemic in South Korea in reducing disease burden. We projected that the vaccination program can reduce the overall attack rate to 3.9% from 6.9% without vaccination, over 150 days, starting from 5 July 2021. The highest relative reduction (50%) was observed among individuals aged 50–59 years. Vaccination markedly reduced adverse outcomes, such as ICU hospitalizations and deaths, decreasing them by 45% and 43%, respectively. In the presence of the Delta variant, vaccination is expected to reduce the overall attack rate to 11.9% from 26.9%. Our results indicate that the impact of vaccination can be substantially affected by the emergence of SARS-CoV-2 variants. Furthermore, herd immunity is unlikely to be achieved with the potential emergence of the Delta variant, inconsistent with the blueprint of the South Korean government.

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“…In addition, the study explains how memory B cells develop properly following the administration of mRNA vaccines, supporting the idea that further enhancement of antibody production is stimulated by a second dose of vaccine given up to 6 months after the first ( 14 ). Similarly, recent epidemiological modeling studies on SARS-CoV-2 showed the effectiveness of single dose vaccination strategy in containing the pandemic more rapidly ( 15 ). The debate is still ongoing among scientists and public health policymakers at both the national and international level ( 16 , 17 ).…”

Section: Introductionmentioning

confidence: 91%

Prioritizing the First Doses of SARS-CoV-2 Vaccine to Save the Elderly: The Case Study of Italy

Pontrelli

Cimini

Roversi

et al. 2021

Front. Public Health

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SARS-CoV-2 is currently causing hundreds of deaths every day in European countries, mostly in not yet vaccinated elderly. Vaccine shortage poses relevant challenges to health authorities, called to act promptly with a scarcity of data. We modeled the mortality reduction of the elderly according to a schedule of mRNA SARS-CoV-2 vaccine that prioritized first dose administration. For the case study of Italy, we show an increase in protected individuals up to 53.4% and a decrease in deaths up to 19.8% in the cohort of over 80's compared with the standard vaccine recalls after 3 or 4 weeks. This model supports the adoption of vaccination campaigns that prioritize the administration of the first doses in the elderly.

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Optimizing vaccine allocation for COVID-19 vaccines shows the potential role of single-dose vaccination

Cited by 116 publications

References 38 publications

Vaccine escape in a heterogeneous population: insights for SARS-CoV-2 from a simple model

Vaccine escape in a heterogeneous population: insights for SARS-CoV-2 from a simple model

Projecting the Impact of SARS-CoV-2 Variants and the Vaccination Program on the Fourth Wave of the COVID-19 Pandemic in South Korea

Prioritizing the First Doses of SARS-CoV-2 Vaccine to Save the Elderly: The Case Study of Italy

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