Publications by authors named "Guilherme Calvet"

Since May 2020, we have been conducting a comprehensive study to understand the natural history of SARS-CoV-2 infection in Rio de Janeiro, Brazil. Our focus has been on following families, systematically collecting respiratory tract swabs and blood samples, monitoring symptoms, and gathering data on vaccine status. This paper aims to describe the household cohort across five epidemic waves of SARS-CoV-2, providing an overview of the collected data and a description of the epidemiological, clinical, and immunological characteristics and incidence of SARS-CoV-2 infection.

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Infectious disease (ID) cohorts are key to advancing public health surveillance, public policies, and pandemic responses. Unfortunately, ID cohorts often lack funding to store and share clinical-epidemiological (CE) data and high-dimensional laboratory (HDL) data long term, which is evident when the link between these data elements is not kept up to date. This becomes particularly apparent when smaller cohorts fail to successfully address the initial scientific objectives due to limited case numbers, which also limits the potential to pool these studies to monitor long-term cross-disease interactions within and across populations.

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causes the vast majority of malaria cases in Brazil. The lifecycle of this parasite includes a latent stage in the liver, the hypnozoite. Reactivation of hypnozoites induces repeated relapses.

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Objective: To identify and summarise the evidence on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA detection and persistence in body fluids associated with sexual activity (saliva, semen, vaginal secretion, urine and faeces/rectal secretion).

Eligibility: All studies that reported detection of SARS-CoV-2 in saliva, semen, vaginal secretion, urine and faeces/rectal swabs.

Information Sources: The WHO COVID-19 database from inception to 20 April 2022.

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We generated 238 Zika virus (ZIKV) genomes from 135 persons in Brazil who had samples collected over 1 year to evaluate virus persistence. Phylogenetic inference clustered the genomes together with previously reported ZIKV strains from northern Brazil, showing that ZIKV has been remained relatively stable over time. Temporal phylogenetic analysis revealed limited within-host diversity among most ZIKV-persistent infected associated samples.

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  • * A total of 260 individuals were monitored for 12 months, revealing that Zika virus RNA was detectable for long periods, especially in semen, and various factors influenced how quickly the virus cleared from different fluids.
  • * The research highlighted the potential for recurrent detection of Zika virus even after it was cleared, underscoring the importance of ongoing monitoring and prevention strategies to manage its transmission.
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Background: There is interest in lingering non-specific symptoms after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, referred to as Long coronavirus disease 2019 (Long COVID-19). It remains unknown whether the risk of Long COVID-19 is associated with pre-existing comorbidities or initial COVID-19 severity, including infections due to new Omicron lineages which predominated in 2023.

Objectives: The aim of this case report was to characterize the clinical features of acute XBB.

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Background: Chikungunya can cause persistent chronic joint pain. Knowledge of the risk factors for disease progression is important for preventing and controlling complications. This study aimed to identify factors associated with chronic joint pain.

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Background: Malaria is endemic and represents an important public health issue in Brazil. Knowledge of risk factors for disease progression represents an important step in preventing and controlling malaria-related complications. Reports of severe forms of Plasmodium vivax malaria are now becoming a common place, but respiratory complications are described in less than 3% of global literature on severe vivax malaria.

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Background: Early studies have highlighted the possible development of dysgeusia and anosmia in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and these manifestations should be considered a potential indication of coronavirus disease 19 (COVID-19). As potential contributors to these symptoms, dentists should perform careful oral and oropharyngeal examinations and document suspicious oral lesions in patients with COVID-19, especially in those who complain of loss of taste and smell. The study's objective was to assess the prevalence of oral manifestations among ambulatory unvaccinated symptomatic patients with suspected COVID-19 during the acute phase of the disease.

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The occurrence of acute paracoccidioidomycosis (PCM) in urban areas of the Rio de Janeiro state, Brazil, has emerged in recent years. Therefore, young populations, including pregnant women, are at a higher risk of infection. Furthermore, young women undergoing itraconazole treatment for PCM have increased chances to get pregnant because this medication may reduce the effectiveness of contraceptives.

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  • This study tracked people with COVID-19 and their household contacts in Rio de Janeiro from April 2020 to June 2022, focusing on reinfections.
  • Ninety-eight reinfections were noted, with a significant number confirmed through genomic analysis; vaccination was effective against reinfection before the Omicron variant, but not afterward.
  • The results indicate that while reinfections tended to be milder, vaccines may not effectively prevent all infections, emphasizing the need for updated vaccines and regular boosters like those used for flu.
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Zika virus (ZIKV) is an emerging pathogen that causes devastating congenital defects. The overlapping epidemiology and immunologic cross-reactivity between ZIKV and dengue virus (DENV) pose complex challenges to vaccine design, given the potential for antibody-dependent enhancement of disease. Therefore, classification of ZIKV-specific antibody targets is of notable value.

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  • - This study explored how SARS-CoV-2 spreads within households, focusing on the role of children and their adult caregivers, particularly examining whether children mostly contracted the virus from symptomatic adults, especially mothers.
  • - Conducted in Brazil from April 2020 to July 2022, the study involved 1,256 participants across 298 households, revealing that children are less likely to transmit the virus compared to adults, especially if the adult is symptomatic or unvaccinated.
  • - Findings highlighted that vaccinated adults not only had a lower chance of severe illness but also reduced the risk of infecting their household members, suggesting implications for similar urban populations in Latin America.
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COVID-19 vaccines have dramatically reduced rates of severe infection requiring hospitalization. However, SARS-CoV-2 variants have reduced vaccine effectiveness at preventing any symptomatic infection. This real-world study analyzed binding and neutralizing antibodies generated after complete vaccination and boosting across three vaccine platforms.

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Background: While nasopharyngeal (NP) swabs are considered the gold standard for severe acute respiratory coronavirus 2 (SARS-CoV-2) real-time reverse transcriptase-polymerase chain reaction (RT-PCR) detection, several studies have shown that saliva is an alternative specimen for COVID-19 diagnosis and screening.

Methods: To analyze the utility of saliva for the diagnosis of COVID-19 during the circulation of the Omicron variant, participants were enrolled in an ongoing cohort designed to assess the natural history of SARS-CoV-2 infection in adults and children. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen's kappa coefficient were calculated to assess diagnostic performance.

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Introduction: Acute febrile illnesses (AFI) are a frequent chief complaint in outpatients. Because the capacity to investigate the causative pathogen of AFIs is limited in low- and middle-income countries, patient management may be suboptimal. Understanding the distribution of causes of AFI can improve patient outcomes.

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Background: Antiretroviral therapy use has led to a decline in HIV-related mortality yet disparities by gender and/or sexual orientation may exist. In this study, we estimated hazards of death in people living with HIV (PLWH) according to gender and sexual orientation.

Methods: We included PLWH ≥ 18 years enrolled between 2000 and 2018 at INI/Fiocruz, Rio de Janeiro, Brazil.

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Purpose: To better understand the household transmission of SARS-COV-2 in a low-resource community in Rio de Janeiro during the COVID-19 pandemic (2020-2022).

Participants: This is an open prospective cohort study of children ≤12 years old and their household contacts. During home visits over 24 months, we collected data on sociodemographic characteristics, behavioural data, clinical manifestations of SARS-CoV-2, vaccination status, SARS-CoV-2 (reverse transcription-polymerase chain reaction) RT-PCR and anti-S antibody tests.

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Brazilian spotted fever, a zoonotic disease transmitted by ticks, is caused by Rickettsia rickettsii. We report a fulminant case of this zoonosis in a healthy 46-year-old military man in the urban region of Rio de Janeiro city, in October, 2021. Ticks and capybaras (Amblyomma sculptum, Hydrochoerus hydrochaeris, respectively) were identified in the military fields, pointing to the participation of this large synanthropic rodent, recognized as an efficient amplifier host of Rickettsia rickettsii in Brazil.

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Background: Chikungunya is a viral disease that is transmitted by mosquitoes. It is characterized by an acute onset of fever and severe arthralgia.

Methods: We describe six cases of acute and post-acute chikungunya in which viral RNA was detected in semen.

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Article Synopsis
  • A significant portion of rash diseases (19%) and acute febrile illnesses (40%) in patients lack a clear cause, with the study focusing on identifying Parvovirus B19 and herpesvirus infections in these cases in Rio de Janeiro.
  • The study included 114 participants (54 children and 60 adults), using various diagnostic methods such as real-time PCR and ELISA to assess viral infections.
  • Findings indicated low prevalence rates of B19V and herpesviruses among patients, emphasizing the need for their consideration in laboratory diagnoses for unexplained RD and AFI cases.
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Background: Incidence rates of SARS-CoV-2 infections in low-resource communities can inform vaccination strategies and non-pharmaceutical interventions (NPIs). Our objective was to estimate incidence over four epidemic waves in a slum in Rio de Janeiro, a proxy for economically deprived areas in the Global South.

Methods: Prospective cohort of children and household contacts screened for SARS-CoV-2 by PCR and serology (IgG).

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