Effectiveness of face masks in blocking the transmission of SARS-CoV-2: A preliminary evaluation of masks used by SARS-CoV-2-infected individuals.

In 2019, a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is transmitted via the airborne route, caused a new pandemic namely, "coronavirus disease 2019" (COVID-19). Although the effectiveness of face masks to prevent the transmission of SARS-CoV-2 is debated, no study has evaluated the virus-blocking efficacy of masks used by patients. We aimed to evaluate this efficacy of masks used by SARS-CoV-2-infected individuals. Data, masks used, and nasopharyngeal swab samples were obtained from these patients. Forty-five paired samples of nasopharyngeal swabs and masks were obtained and processed; the majority of masks were woven. Viral RNAs were amplified using quantitative reverse-transcription polymerase chain reaction and detected only on the inner parts of masks. Median viral load (VL) values of swabs and masks were 1.954x106 and 2,51x103, respectively. Statistically, there was a difference of approximately 1000 RNA copies/mL between swabs and masks and no significant difference in VL values among different types of masks. There were statistically significant differences in VL values between men and women and between symptomatic and asymptomatic patients. Our findings suggest the blocking of virus transmission by different types of masks and reinforce the use of masks by both infected and non-infected individuals.

Human pegivirus-1 infection in kidney transplant recipients: A single-center experience.

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. In the posttransplant period, the induced immunosuppression leads to an increased risk of developing infectious diseases, a leading cause of death after kidney transplantation. Human pegivirus-1 (HPgV-1) is considered a nonpathogenic human virus and is highly frequent in individuals parenterally exposed, however, its impact on kidney transplantation outcome is poorly understood. Given the scarcity of epidemiological data for this infection on organ recipients in Brazil, we conducted a study in a single center for kidney transplantation in Rio de Janeiro, aiming to determine HPgV-1 prevalence and genotypic distribution. Serum samples from 61 renal recipients, followed up for the first year after transplantation, were evaluated for viral RNA and genotypes were determined by sequencing of the 5'-untranslated region. HPgV-1 RNA was detected in 36.1% (22/61) of patients. Genotype 2 was the most commonly found (80.9%), followed by genotypes 3 (9.5%), 1, and 5, in 4.8% each. Statistical comparisons did not reveal any significant impact of HPgV-1 in patient outcome. Further epidemiologic studies are needed to understand if immunosuppression may interfere in HPgV-1 persistence rates and if viremia might impact graft dysfunction rates in kidney recipients.

Yellow fever epizootics in non-human primates, Southeast and Northeast Brazil (2017 and 2018).

BACKGROUND: Yellow fever (YF) is a severe, infectious, but non-communicable arboviral hemorrhagic disease. In the last decades, yellow fever virus (YFV) infections have been prevalent in endemic areas in Brazil, affecting human and non-human primate (NHP) populations. Monitoring of NHP infection started in 1999, and reports of epizootic diseases are considered important indicators of viral transmission, particularly in relation to the sylvatic cycle. This study presents the monitoring of YFV by real-time RT-PCR and the epidemiological findings related to the deaths of NHPs in the south-eastern states and in the north-eastern state of Bahia, during the outbreak of YF in Brazil during 2017 and 2018. METHODS: A total of 4198 samples from 2099 NHPs from south-eastern and north-eastern Brazilian states were analyzed by real-time reverse transcription polymerase chain reaction (rtRT-PCR). RESULTS: A total of 4198 samples from 2099 NHPs from south-eastern and north-eastern Brazilian states were collected between 2017 and 2018. The samples were subjected to molecular diagnostics for YFV detection using real-time reverse transcription polymerase chain reaction (rtRT-PCR) techniques. Epizootics were coincident with human YF cases. Furthermore, our results showed that the YF frequency was higher among marmosets (Callithrix sp.) than in previous reports. Viremia in species of the genus Alouatta and Callithrix differed greatly. DISCUSSION: Our results indicate a need for further investigation of the role of Callithrix spp. in the transmission cycles of YFV in Brazil. In particular, YFV transmission was observed in a region where viral circulation has not been recorded for decades and thus vaccination has not been previously recommended. CONCLUSIONS: This highlights the need to straighten epizootic surveillance and evaluate the extent of vaccination programmes in Brazil in previously considered "YFV-free" areas of the country.