Comparative outcomes of hemodialysis patients facing pre‐<scp>Omicron</scp> and <scp>Omicron COVID</scp>‐19 epidemics

Beppu, Hiroko; Fukuda, Tatsuya; Otsubo, Naoya; Akihisa, Taro; Kawanishi, Tomoko; Ogawa, Toshie; Abe, Yasutomo; Endo, Mariko; Hanawa, Tomohide; Sugita, Chise; Kikkawa, Yoshiaki; Yamada, Tetsuya; Wakai, Sachiko

doi:10.1111/1744-9987.14067

Cited by 1 publication

(2 citation statements)

References 23 publications

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“…Characterized by many mutations compared to its predecessors, Omicron exhibits elevated transmissibility and the ability to evade the immune response [6,7]. However, works indicate a lower severity regarding disease outcomes [5][6][7][8][9].…”

Section: Plos Onementioning

confidence: 99%

“…Notably, 2022 marked the highest peak in reported cases, with a drastic reduction in the Case Fatality Rate (CFR) compared to earlier stages. The emergence of the Omicron variant in early 2022, characterized by high transmissibility and lower severity, also shaped the dynamics of the pandemic [4][5][6][7][8][9]. We also highlight that at the beginning of January 2022, Brazil had 78% and 67% of the population vaccinated against Covid-19 with at least one dose and fully vaccinated, respectively [4].…”

Section: Introductionmentioning

confidence: 97%

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Estimating time-varying epidemiological parameters and underreporting of Covid-19 cases in Brazil using a mathematical model with fuzzy transitions between epidemic periods

Lima,

Tupinambás,

Guimarães

2024

PLoS ONE

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Our study conducts a comprehensive analysis of the Covid-19 pandemic in Brazil, spanning five waves over three years. We employed a novel Susceptible-Infected-Recovered-Dead-Susceptible (SIRDS) model with a fuzzy transition between epidemic periods to estimate time-varying parameters and evaluate case underreporting. The initial basic reproduction number (R0) is identified at 2.44 (95% Confidence Interval (CI): 2.42–2.46), decreasing to 1.00 (95% CI: 0.99–1.01) during the first wave. The model estimates an underreporting factor of 12.9 (95% CI: 12.5–13.2) more infections than officially reported by Brazilian health authorities, with an increasing factor of 5.8 (95% CI: 5.2–6.4), 12.9 (95% CI: 12.5–13.3), and 16.8 (95% CI: 15.8–17.5) in 2020, 2021, and 2022 respectively. Additionally, the Infection Fatality Rate (IFR) is initially 0.88% (95% CI: 0.81%–0.94%) during the initial phase but consistently reduces across subsequent outbreaks, reaching its lowest value of 0.018% (95% CI: 0.011–0.033) in the last outbreak. Regarding the immunity period, the observed uncertainty and low sensitivity indicate that inferring this parameter is particularly challenging. Brazil successfully reduced R0 during the first wave, coinciding with decreased human mobility. Ineffective public health measures during the second wave resulted in the highest mortality rates within the studied period. We attribute lower mortality rates in 2022 to increased vaccination coverage and the lower lethality of the Omicron variant. We demonstrate the model generalization by its application to other countries. Comparative analyses with serological research further validate the accuracy of the model. In forecasting analysis, our model provides reasonable outbreak predictions. In conclusion, our study provides a nuanced understanding of the Covid-19 pandemic in Brazil, employing a novel epidemiological model. The findings contribute to the broader discourse on pandemic dynamics, underreporting, and the effectiveness of health interventions.

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