Age-dependent effects on infectivity and susceptibility to SARS-CoV-2 infection: results from nationwide contact tracing data in Greece

Bistaraki, Angeliki; Roussos, Sotirios; Tsiodras, Sotirios; Sypsa, Vana

doi:10.1080/23744235.2021.1995627

“…We identified 2097 records (1791 from PubMed, 306 from medRxiv, and 2 from reference lists of eligible articles) published between June 18, 2021, and March 8, 2022 (eFigure 1 in the Supplement ). Fifty-eight new studies 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 (eTable 2 in the Supplement ) were combined with 77 studies from ou...…”

Section: Resultsmentioning

confidence: 99%

Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status

Madewell

¹

,

Yang

²

,

Longini

³

et al. 2022

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“…Since vaccine efficacy is, at the current time, estimated only for the status "fully vaccinated" in Germany without distinguishing between different vaccines, we solely distinguish between "unvaccinated" and "vaccinated" individuals in the model, regardless of the make of the received doses. Following the example of Scholz et al [21], we further assume that children and adolescents have reduced susceptibility to the virus and a reduced base transmissibility if infected, as was observed in Germany, Israel, and Greece [22][23][24]. In the discussed time FIG.…”

Section: Methodsmentioning

confidence: 98%

“…[12,18), [18,60), and 60+ [25]. In order to match this distribution approximately, we calibrate the base susceptibility (i. e. susceptibility without vaccination) and infectiousness of our model by assuming that children are 72% as susceptible and 63% as infectious as adults (72%/81% for adolescents), which is larger than what was observed for the wild type [23,24]. However, since the currently predominant B.1.617.2 variant (Delta) was generally observed to be more infectious than the wild type [26], such an increase is plausible.…”

Section: Methodsmentioning

confidence: 99%

Germany's current COVID-19 crisis is mainly driven by the unvaccinated

Maier¹,

Wiedermann²,

Burdinski³

et al. 2021

Preprint

0

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Vaccines are the most powerful pharmaceutical tool to combat the COVID-19 pandemic. While the majority (about 65%) of the German population were fully vaccinated, incidence started growing exponentially in October 2021 with about 41% of recorded new cases aged twelve or above being symptomatic breakthrough infections, presumably also contributing to the dynamics. At the time, it (i) remains elusive how significant this contribution is and (ii) whether targeted non-pharmaceutical interventions (NPIs) may stop the amplification of the ongoing crisis. Here, we estimate that about 67%-76% of all new infections are caused by unvaccinated individuals, implying that only 24%-33% are caused by the vaccinated. Furthermore, we estimate 38%-51% of new infections to be caused by unvaccinated individuals infecting other unvaccinated individuals. In total, unvaccinated individuals are expected to be involved in 8-9 of 10 new infections. We further show that decreasing the transmissibility of the unvaccinated by, e. g. targeted NPIs, causes a steeper decrease in the effective reproduction number R than decreasing the transmissibility of vaccinated individuals, potentially leading to temporary epidemic control. Furthermore, reducing contacts between vaccinated and unvaccinated individuals serves to decrease R in a similar manner as increasing vaccine uptake. Taken together, our results contribute to the public discourse regarding policy changes in pandemic response and highlight the importance of combined measures, such as vaccination campaigns and contact reduction, to achieve epidemic control and preventing an overload of public health systems.

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“…Since vaccine efficacy is, at the current time, estimated only for the status "fully vaccinated" in Germany without distinguishing between different vaccines, we solely distinguish between "unvaccinated" and "vaccinated" individuals in the model, regardless of the make of the received doses. Following the example of Scholz et al [21], we further assume that children and adolescents have reduced susceptibility to the virus and a reduced base transmissibility if infected, as was observed in Germany, Israel, and Greece [22][23][24]. In the discussed time FIG.…”

Section: Methodsmentioning

confidence: 99%

“…[12,18), [18,60), and 60+ [25]. In order to match this distribution approximately, we calibrate the base susceptibility (i. e. susceptibility without vaccination) and infectiousness of our model by assuming that children are 72% as susceptible and 63% as infectious as adults (72%/81% for adolescents), which is larger than what was observed for the wild type [23,24]. However, since the currently predominant B.1.617.2 variant (Delta) was generally observed to be more infectious than the wild type [26], such an increase is plausible.…”

Section: Methodsmentioning

confidence: 99%

Germany’s current COVID-19 crisis is mainly driven by the unvaccinated

Maïer

¹

,

Wiedermann

²

,

Burdinski

³

et al. 2021

Preprint

View full text Add to dashboard Cite

Vaccines are the most powerful pharmaceutical tool to combat the COVID-19 pandemic. While the majority (about 65%) of the German population were fully vaccinated, incidence started growing exponentially in October 2021 with about 41% of recorded new cases aged twelve or above being symptomatic breakthrough infections, presumably also contributing to the dynamics. At the time, it (i) remains elusive how significant this contribution is and (ii) whether targeted non-pharmaceutical interventions (NPIs) may stop the amplification of the ongoing crisis. Here, we estimate that about 67%–76% of all new infections are caused by unvaccinated individuals, implying that only 24%–33% are caused by the vaccinated. Furthermore, we estimate 38%–51% of new infections to be caused by unvaccinated individuals infecting other unvaccinated individuals. In total, unvaccinated individuals are expected to be involved in 8–9 of 10 new infections. We further show that decreasing the transmissibility of the unvaccinated by, e. g. targeted NPIs, causes a steeper decrease in the effective reproduction number ℛ than decreasing the transmissibility of vaccinated individuals, potentially leading to temporary epidemic control. Furthermore, reducing contacts between vaccinated and unvaccinated individuals serves to decrease ℛ in a similar manner as increasing vaccine uptake. Taken together, our results contribute to the public discourse regarding policy changes in pandemic response and highlight the importance of combined measures, such as vaccination campaigns and contact reduction, to achieve epidemic control and preventing an overload of public health systems.

show abstract

Age-dependent effects on infectivity and susceptibility to SARS-CoV-2 infection: results from nationwide contact tracing data in Greece

Cited by 16 publications

References 36 publications

Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status

Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status

Germany's current COVID-19 crisis is mainly driven by the unvaccinated

Germany’s current COVID-19 crisis is mainly driven by the unvaccinated

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