Household transmission of COVID-19 according to index case: children, parents, and healthcare workers.

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.

Comparative analysis of three point-of-care lateral flow immunoassays for detection of anti-SARS-CoV-2 antibodies: data from 100 healthcare workers in Brazil.

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: <30 (n=26), 30-59 (n=42), and >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.

Asymptomatic COVID-19 in hospital visitors: The underestimated potential of viral shedding.

In a single day, six of 150 (4%) asymptomatic visitors were diagnosed with COVID-19 at a hospital with a universal masking policy. Two inpatients (contacts) subsequently developed symptoms. More rigorous protective measures during visitation periods may need to be included in infection control practices to reduce nosocomial transmissions.

No benefit of hydroxychloroquine on SARS-CoV-2 viral load reduction in non-critical hospitalized patients with COVID-19.

BACKGROUND: Some studies have shown that hydroxychloroquine (HCQ) is an effective drug in reducing the in vitro replication of SARS-CoV-2. However, the in vivo effect of HCQ still unclear. OBJECTIVES: This study aims to evaluate viral load clearance in patients with COVID-19 who underwent HCQ treatment in comparison with a control group that did not receive the drug. STUDY DESIGN: This prospective study comprised consecutive viral load measurements in patients with COVID-19 hospitalized with a moderate illness. Patients received 400 mg of HCQ every 12 h for 10 days according to the medical decision. Nasal swab samples were collected from patients during early, intermediary, and final clinical stage of COVID-19. RESULTS: A total of 155 samples were collected from 66 patients with COVID-19 (60% female), with a median age of 58 years. The viral load between studied groups, assumed as a semiquantitative measure of cycle threshold (Ct) values, presented no significant difference within the three consecutive measures (ΔCt) (p > 0.05). We also analyzed the ΔCt viral load at different intervals of sample collection (Δt < 7; 7-12; and > 12 days) without significant differences at any ΔCt (p > 0.05). CONCLUSION: In this study, we did not observe any change in viral load reduction in vivo with the use of HCQ.

COVID-19 in health care workers in a university hospital during the quarantine in São Paulo city

Abstract Health care workers (HCW) are at a higher risk of being infected in their workplace. Out of a total of 466 HCW of Hospital São Paulo with influenza-like illnesses or any clinical suspicion of COVID-19 were tested for COVID-19 by RT-PCR for SARS-CoV-2 169 (36%) turned out positive and were analyzed by type of exposure and hospital occupation. Data of HCW household locations were also obtained. Logistic workers had the highest positivity rate for SARS-CoV-2 (p = 0.002), while nurse technicians had the highest rate among those reporting routine contacts with patients (p = 0.001). Physicians presented the lowest rate of infection, although living in most affected districts (p < 0.001). Policies and adequate training for all hospital employees may improve prevention of COVID-19 among all health care service categories.

COVID-19 in health care workers in a university hospital during the quarantine in São Paulo city.

Health care workers (HCW) are at a higher risk of being infected in their workplace. Out of a total of 466 HCW of Hospital São Paulo with influenza-like illnesses or any clinical suspicion of COVID-19 were tested for COVID-19 by RT-PCR for SARS-CoV-2 169 (36%) turned out positive and were analyzed by type of exposure and hospital occupation. Data of HCW household locations were also obtained. Logistic workers had the highest positivity rate for SARS-CoV-2 (p = 0.002), while nurse technicians had the highest rate among those reporting routine contacts with patients (p = 0.001). Physicians presented the lowest rate of infection, although living in most affected districts (p < 0.001). Policies and adequate training for all hospital employees may improve prevention of COVID-19 among all health care service categories.