The increase in the risk of severity and fatality rate of covid-19 in southern Brazil after the emergence of the Variant of Concern (VOC) SARS-CoV-2 P.1 was greater among young adults without pre-existing risk conditions

  1. André Ricardo Ribas Freitas
  2. Daniele Rocha Queiróz Lemos
  3. Otto Albuquerque Beckedorff
  4. Luciano Pamplona de Góes Cavalcanti
  5. Andre M Siqueira
  6. Regiane Cristina Santos de Mello
  7. Eliana N C Barros

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Abstract

Background

The SARS-CoV-2 P.1 variant has been considered as “variant of concern (VOC)” since the end of 2020 when it was firstly identified in the Brazilian state of Amazonas and from there spread to other regions of Brazil. This variant was associated with an increase in transmissibility and worsening of the epidemiological situation in the places where it was detected. The aim of this study was to analyze the severity profile of covid-19 cases in the Rio Grande do Sul state, southern region of Brazil, before and after the emergence of the P.1 variant, considering also the context of the hospitals overload and the collapse of health services.

Methods

We analyzed data from the Influenza Epidemiological Surveillance Information System, SIVEP-Gripe (Sistema de Informação de Vigilância Epidemiológica da Gripe) and compare two epidemiological periods: the “first wave” comprised by cases occurred during November and December 2020 (EW 45 to 53) and the “second wave” with cases occurred in February 2021 (EW 5 to 8), considering that in this month there was a predominance of the new variant P.1. We calculated the proportion of severe forms among the total cases of covid-19, the case fatality rates (CFR) and hospital case fatality rate (hCFR) over both waves time set using the date of onset of symptoms as a reference. We analyzed separately the patients without pre-existing conditions of risk, by age and sex. For comparison between periods, we calculated the Risk Ratio (RR) with their respective 95% confidence intervals and the p-values.

Findings

We observed that in the second wave there were an increase in the proportion of severe cases and covid-19 deaths among younger age groups and patients without pre-existing conditions of risk. The proportion of people under the age of 60 among the cases that evolved to death raised from 18% (670 deaths) in November and December (1 st wave) to 28% (1370 deaths) in February (2 nd wave). A higher proportion of patients without pre-existing risk conditions was also observed among those who evolved to death due to covid-19 in the second wave (22%, 1,077 deaths) than in the first one (13%, 489 deaths). The CFR for covid-19 increased overall and in different age groups, in both sexes. The increase occurred in a greatest intensity in the population between 20 and 59 years old and among patients without pre-existing risk conditions. Female 20 to 39 years old, with no pre-existing risk conditions, were at risk of death 5.65 times higher in February (95%CI = 2.9 - 11.03; p <0.0001) and in the age group of 40 and 59 years old, this risk was 7.7 times higher (95%CI = 5.01-11.83; p <0.0001) comparing with November-December.

Interpretation

Our findings showed an increase in the proportion of young people and people without previous illnesses among severe cases and deaths in the state of RS after the identification of the local transmission of variant P.1 in the state. There was also an increase in the proportion of severe cases and in the CFR, in almost all subgroups analyzed, this increase was heterogeneous in different age groups and sex. As far as we know, these are the first evidences that the P.1 variant can disproportionately increase the risk of severity and deaths among population without pre-existing diseases, suggesting related changes in pathogenicity and virulence profiles. New studies still need to be done to confirm and deepen these findings.

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  1. ScreenIT

    SciScore for 10.1101/2021.04.13.21255281: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsIRB: This study did not require approval from any research ethics committee as all data were anonymous and obtained from open and public open source databases.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    The data were analyzed using the STATA 16 software and followed the recommendations of the REporting of studies Conducted using Observational Routinely-collected Data (RECORD) guidelines[12], attached checklist.
    STATA
    suggested: (Stata, RRID:SCR_012763)
    RECORD
    suggested: (RECORD, RRID:SCR_009097)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Strengths and limitations: One of the strengths of our study is its size, which includes all cases of covid-19 from the RS state officially reported to the Ministry of Health during a period when the P.1 variant was introduced in the state. Another strength is the fact that it is studying a period in which there was not yet a complete depletion of health resources in the studied place. This study has some limitations, such as the use of secondary data, which can present problems in the quality, integrity and delays in the recorded data. Patients were not tested individually to see if it was a strain of SARS-CoV-2, for comparison of groups. We assume that as of February, the proportion of variant P.1 among patients with covid-19 was higher than in November and December, although it is quite likely, considering other studies in reference units in the state, this assumption is quite inaccurate. The use of CFR and hCFR as severity indicators based on epidemiological surveillance data can lead to different types of bias, however, it remains a useful tool, especially in emergency situations in public health.[17–20] This is an initial analysis in which a limited number of available variables have been assessed and additional individual risk factors have not been explored in depth. Despite these limitations, the results obtained in this study suggest a temporal association between the emergence of variant P.1 and severity indicators related to covid-19 measured by CFR and hCFR, in ad...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  2. Version published to 10.1101/2021.04.13.21255281v1 on medRxiv