Luciano Kleber de Souza Luna

Background and Objectives: Respiratory syncytial virus (RSV) is responsible for most cases of acute viral bronchiolitis (AVB) in childhood. The association of factors such as RSV subtype, viral load, and viral coinfection with severe disease is controversial. The objective is to describe the viral load dynamics of RSV in children under 2 years with AVB, including the first viral load, peak viral load, viral decay, and any possible association with severe disease. Methods: 73 inpatients with AVB and confirmed RSV infection were included. Viral load was obtained through nasal swab samples daily during hospitalization and weekly after discharge until absence of detection. Results: 44 of the patients were male, the mean age was 5.76 months, and comorbidities were found in 15 (20.5%) of the patients. 54 (74%) of the patients had the peak viral load between the 4th and the 7th day of symptom onset. The mean duration of viral detection was 12.5 days. There was no association between the first and peak viral load with markers of severe disease. However, association was found between viral persistence exceeding 10 days and the following factors: longer hospitalization period (p=0.009), length of ventilation support (p=0.044), length of invasive mechanical ventilation (p=0.035), prolonged requirement of nutritional support (p=0.038), and a longer course of antibiotic treatment (p=0.024). Age was inversely correlated with most of the severity outcomes. Conclusion: Despite the lack of association between RSV viral load values and disease severity, prolonged viral shedding was associated with several adverse outcomes, which can contribute to a better understanding of RSV disease, particularly as several interventions are anticipated to become available in the coming years.

Respiratory Syncytial Virus (RSV) poses a global health concern, particularly in young children, the elderly, and those immunosuppressed. RSV viral load is essential for understanding transmission, disease severity, prevention, and treatment. This retrospective study aimed to analyze the frequency rates and viral loads of RSV infections in different patient cohorts and age groups over an eight-year period in a university hospital in São Paulo, Brazil. This study analyzed 1380 immunocompetent (IC) and immunosuppressed (IS) patients with acute respiratory tract infections. IC included patients suspected of having severe acute respiratory syndrome caused by influenza A (H1N1)pdm09 virus (SARS H1N1), chronic heart disease (HD), and those receiving primary care service (PC). The IS comprised transplant patients and individuals with human immunodeficiency virus (HIV) infection. Respiratory samples were collected between 2005 and 2013. RSV detection and quantification were performed by RT-qPCR. Viral load was expressed as Log10 copies of RNA/mL. The overall RSV infection rate was 17.3%, with higher rates in children (23.9%) than in adults (12.9%), particularly in children under two years of age (28.2%). Children in the SARS H1N1 and PC subgroups had higher infection rates (16.4% and 34.9%, respectively), with the highest rate in PC children aged 1 to <2 years (45.45%). Adults with HD had a significantly higher frequency rate (27.83%) than those in the SARS H1N1 (2.65%) and IS (15.16%) subgroups. The RSV viral load ranged from 2.43 to 10.15 Log10 RNA copies/mL (mean ±SD = 5.82 ± 2.19). Hospitalized patients had significantly higher viral loads (7.34 ± 1.9) than outpatients (4.38 ± 1.89). Elderly bone marrow transplant patients also had significantly higher viral loads (7.57 ± 2.41) than younger adults (5.12 ± 1.87). This study provides insights into the patterns and impacts of RSV infection in different patient cohorts in Brazil, contributing to developing effective prevention, treatment, and control strategies. Further investigations are needed to understand the susceptibility and risk factors associated with RSV infection.

The first SARS-CoV-2 intrafamilial transmission was investigated in China. We evaluated the dynamics of SARS-CoV-2 transmission in 242 individuals from 60 family clusters, including 30 healthcare workers (HCW) and 30 patients, in São Paulo city. Sixty index cases with COVID-19 were selected, being 30 HCW index cases from Hospital São Paulo (HSP) and its 93 household contacts and 30 index case patients from Hospital Infantil Sabará (HIS) and its 89 household contacts. Asymptomatic and symptomatic individuals participating were tested for COVID-19. The secondary attack rates in the family clusters of HCW and HIS patients were 37.63% and 68.54%, respectively. Considering all households, the transmission from adults to children was 55.4%, while the transmission from children to children was 37.5%. Children were more infected if the index case was an adult, suggesting that children were less competent to transmit. The average time for a household to be COVID-19 positive was 4 and 3 days for HCW and HIS patients. Although HCW have a higher risk of infection and social vulnerability, the secondary attack rate was lower than that observed for HIS patients, possibly because HCW are more aware of transmission risks than the general community.

Acute viral bronchiolitis is the major cause of hospital admissions in children under 2 years of age, and respiratory syncytial virus (RSV) can be responsible for up to 80% of these infections. We aimed to describe RSV dynamics among hospitalized children with bronchiolitis. Upper respiratory samples of 101 hospitalized patients were collected and submitted to RSV detection by a quantitative real-time RT-PCR to assess viral load (Log₁₀ RNA copies/mL). Seventy-two patients were positive for RSV infection, of which 38 (52.7%) could be followed up until RSV was no longer detected. The first RSV RT-qPCR was carried out on average on the 5th day of symptom onset. Thirty-six patients (94.7%) were still shedding RSV after 7 days, and 9 (23.6%) after 14 days of symptoms onset. Only 2 patients (5.2%) were still shedding RSV after 21 days. Only 7 of the followed patients (18.9%) were submitted to intubation. There was no difference between the viral load of the first collected sample and the viral persistence of patients with comorbidities, who needed intensive care unit and who needed intubation. These data could help understand RSV dynamics and future studies and treatments to come.

Cholesteatomas are frequent middle ear benign tumors of unknown etiology. Infectious agents have been considered as possible contributing factors in the pathogenesis of cholesteatomas. Aiming to investigate the presence of respiratory viruses in primary cholesteatoma tissues, 26 formalin‐fixed paraffin‐embedded primary cholesteatoma tissues obtained from patients seen at the of the Clinical Hospital of the University of São Paulo School of Medicine, in Ribeirão Preto, Brazil were tested by real‐time polymerase chain reaction (PCR). Considering the PCR results, 35% of the tissues were positive for human rhinovirus (HRV), 15.3% for human enterovirus (EV), 3.8% for human metapneumovirus (HMPV), and 3.8% for human bocavirus (HBoV). Serial immunohistochemistry for virus antigens and cell surface markers evidenced that the viruses were associated with fibroblasts, dendritic cells, macrophages, B lymphocytes, CD4⁺, and CD8⁺ T lymphocytes. These findings indicate for the first time the presence of active respiratory virus infection in primary cholesteatoma tissues, suggesting that persisting virus infection in the middle could play a role in the pathogenesis and evolution of cholesteatomas.

Objective To assess the COVID-19 frequency rates in hospitalized patients (HP) and healthcare workers (HCW), viral load inference, and the impact of vaccination and variants of concern (VOC) during the first pandemic wave. Methods We evaluated the COVID-19 diagnostics at Hospital São Paulo, Brazil, from March 2020 to April 2021, in 10,202 samples (6,502 HP and 3,700 HCW) tested by RT-qPCR, inferring viral load by cycle threshold (Ct) values, and frequency rates. Results SARS-CoV-2 was detected in 31.27% of individuals (32.23% HP and 29.80% HCW). The mean age of HP positives was 57.26 ± 18.29 years (median = 59), with a mean Ct value of 25.55 ± 6.07. Neither age nor Ct values in both groups have significantly differed during the first and second waves or even since the predominance of VOC P.1 on March 2021. Conclusions The COVID-19 epidemic curves of HP and HCW accompanied the variations reported in São Paulo city, as well as the variation of hospitalization and occupancy of ICU beds. The VOC P.1 has no impact on the viral load, since its predominance in March 2021. The vaccination of HCW may have contributed to a decrease in the positivity rates, although more studies will provide a better understanding of the impact of immunization on the COVID-19 pandemic.

Since the coronavirus disease 2019 (COVID-19) pandemic, Brazil has the third-highest number of confirmed cases and the second-highest number of recovered patients. SARS-CoV-2 detection by real-time RT-PCR is the gold standard but requires a certified laboratory infrastructure with high-cost equipment and trained personnel. However, for large-scale testing, diagnostics should be fast, cost-effective, widely available, and deployed for the community, such as serological tests based on lateral flow immunoassay (LFIA) for IgM/IgG detection. We evaluated three different commercial point-of-care (POC) LFIAs for anti-SARS-CoV-2 IgM and IgG detection in capillary whole blood of 100 healthcare workers (HCW) from São Paulo university hospital previously tested by RT-PCR: (1) COVID-19 IgG/IgM BIO (Bioclin, Brazil), (2) Diagnostic Kit for IgM/IgG Antibody to Coronavirus (SARS-CoV-2) (Livzon, China), and (3) SARS-CoV-2 Antibody Test (Wondfo, China). A total of 84 positives and 16 negatives HCW were tested. The data was also analyzed by the number of days post symptoms (DPS) in three groups: 59 (n=16). The observed sensibility was 85.71%, 47.62%, and 44.05% for Bioclin, Wondfo, and Livzon, respectively, with a specificity of 100% for all LFIA. Bioclin was more sensitive (p<0.01), regardless of the DPS. Thus, the Bioclin may be used as a POC test to monitor SARS-CoV-2 seroconversion in HCW.

First in Manaus in the Brazilian Northern region, the Variant of Concern P.1 traveled 3800 kilometers southeast to endanger Sao Paulo contributing to the collapse of the health system. Here, we show evidence of how fast the VOC P.1 has spread in the most populated city in South America.