Controlling the pandemic during the SARS-CoV-2 vaccination rollout: a modeling study

Viana, João Faro; Dorp, Christiaan H. van; Nunes, Ana V. M.; Gomes, M.J.; Boven, Michiel van; Kretzschmar, Mirjam; Veldhoen, Marc; Rozhnova, Ganna

doi:10.21203/rs.3.rs-358417/v1

Cited by 8 publications

(7 citation statements)

References 44 publications

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“…It is important to note that even after just the first dose of vaccine (in Portugal at this time only the vaccines by AstraZeneca and Pfizer/BioNtech were approved) the levels of IgG generated are substantial and after 3 weeks tend to be even higher than viral infection, at a similar time. These results are important to inform models for most efficient vaccination strategies in the population [ 39 ].…”

Section: Discussionmentioning

confidence: 99%

Longitudinal SARS‐CoV‐2 seroprevalence in Portugal and antibody maintenance 12 months after infection

et al. 2021

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During the COVID‐19 pandemic, Portugal has experienced three distinct SARS‐CoV‐2 infection waves. We previously documented the prevalence of SARS‐CoV‐2 immunity, measured by specific antibodies, in September 2020, 6 months after the initial moderate wave. Here, we show the seroprevalence changes 6 months later, up to the second week of March 2021, shortly following the third wave, which was one of the most severe in the world, and 2 months following the start of the vaccination campaign. A longitudinal epidemiological study was conducted, with a stratified quota sample of the Portuguese population. Serological testing was performed, including ELISA determination of antibody class and titers. The proportion of seropositives, which was 2.2% in September 2020, rose sharply to 17.3% (95% CI: 15.8–18.8%) in March 2021. Importantly, circulating IgG and IgA antibody levels were very stable 6 months after the initial determination and up to a year after initial infection, indicating long‐lasting infection immunity against SARS‐CoV‐2. Moreover, vaccinated people had higher IgG levels from 3 weeks post‐vaccination when compared with previously infected people at the same time post‐infection.

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Section: Discussionmentioning

confidence: 99%

Longitudinal SARS‐CoV‐2 seroprevalence in Portugal and antibody maintenance 12 months after infection

et al. 2021

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“…These results are important to inform models for most efficient vaccination strategies in the population (43).…”

Section: Discussionmentioning

confidence: 97%

Longitudinal SARS-CoV-2 seroprevalence in Portugal and antibody maintenance 12 months after the start of the COVID-19 pandemic

Castro

Gomes²,

Serrano³

et al. 2021

Preprint

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During the COVID-19 pandemic, Portugal has experienced three distinct SARS-CoV-2 infection waves. We previously documented the prevalence of SARS-CoV-2 immunity, measured by specific antibodies, in September 2020, six months after the initial moderate wave. Here we show the seroprevalence changes six months later, up to the second week of March 2021, shortly following the third wave, which was one of the most severe in the world, and two months following the start of the vaccination campaign. A longitudinal epidemiological study was conducted, with a stratified quota sample of the Portuguese population. Serological testing was performed, including ELISA determination of antibody class and titres. The proportion of seropositives, which was 2.2% in September 2020, rose sharply to 17.3% (95% CI: 15.8% – 18.8%) in March 2021. Importantly, circulating IgG and IgA antibody levels were very stable six months after the initial determination and up to a year after initial infection, indicating long-lasting natural immunity against SARS-CoV-2. Moreover, vaccinated people had higher IgG levels from 3 weeks post-vaccination when compared with previously infected people at the same times post-infection.

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“…However, it is unclear how fast the restrictions can be lifted without risking another wave of infections; we need a promising long-term vaccination strategy [ 1 ]. Nevertheless, a successful approach has to take into account several challenges; vaccination logistics and vaccine allocation requires a couple of months [ 2 – 4 ], vaccine eligibility depends on age and eventually serostatus [ 5 ], vaccine acceptance may vary across populations [ 6 ], and more contagious [ 7 ] and escape variants of SARS-CoV-2 that can evade existing immunity [ 8 , 9 ] may emerge, thus posing a persistent risk. Last but not least, disease mitigation is determined by how well vaccines block infection, and thus prevent the propagation of SARS-CoV-2 [ 3 , 4 ], the time to develop effective antibody titers after vaccination, and their efficacy against severe symptoms.…”

Section: Introductionmentioning

confidence: 99%

Relaxing restrictions at the pace of vaccination increases freedom and guards against further COVID-19 waves

et al. 2021

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Mass vaccination offers a promising exit strategy for the COVID-19 pandemic. However, as vaccination progresses, demands to lift restrictions increase, despite most of the population remaining susceptible. Using our age-stratified SEIRD-ICU compartmental model and curated epidemiological and vaccination data, we quantified the rate (relative to vaccination progress) at which countries can lift non-pharmaceutical interventions without overwhelming their healthcare systems. We analyzed scenarios ranging from immediately lifting restrictions (accepting high mortality and morbidity) to reducing case numbers to a level where test-trace-and-isolate (TTI) programs efficiently compensate for local spreading events. In general, the age-dependent vaccination roll-out implies a transient decrease of more than ten years in the average age of ICU patients and deceased. The pace of vaccination determines the speed of lifting restrictions; Taking the European Union (EU) as an example case, all considered scenarios allow for steadily increasing contacts starting in May 2021 and relaxing most restrictions by autumn 2021. Throughout summer 2021, only mild contact restrictions will remain necessary. However, only high vaccine uptake can prevent further severe waves. Across EU countries, seroprevalence impacts the long-term success of vaccination campaigns more strongly than age demographics. In addition, we highlight the need for preventive measures to reduce contagion in school settings throughout the year 2021, where children might be drivers of contagion because of them remaining susceptible. Strategies that maintain low case numbers, instead of high ones, reduce infections and deaths by factors of eleven and five, respectively. In general, policies with low case numbers significantly benefit from vaccination, as the overall reduction in susceptibility will further diminish viral spread. Keeping case numbers low is the safest long-term strategy because it considerably reduces mortality and morbidity and offers better preparedness against emerging escape or more contagious virus variants while still allowing for higher contact numbers (freedom) with progressing vaccinations.

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Controlling the pandemic during the SARS-CoV-2 vaccination rollout: a modeling study

Cited by 8 publications

References 44 publications

Longitudinal SARS‐CoV‐2 seroprevalence in Portugal and antibody maintenance 12 months after infection

Longitudinal SARS‐CoV‐2 seroprevalence in Portugal and antibody maintenance 12 months after infection

Longitudinal SARS-CoV-2 seroprevalence in Portugal and antibody maintenance 12 months after the start of the COVID-19 pandemic

Relaxing restrictions at the pace of vaccination increases freedom and guards against further COVID-19 waves

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