Y380Q novel mutation in receptor-binding domain of SARS-CoV-2 spike protein together with C379W interfere in the neutralizing antibodies interaction.

We aimed to describe the SARS-CoV-2 lineages circulating early pandemic among samples with S gene dropout and characterize the receptor-binding domain (RBD) of viral spike protein. Adults and children older than 2 months with signs and symptoms of COVID-19 were prospectively enrolled from May to October in Porto Alegre, Brazil. All participants performed RT-PCR assay, and samples with S gene dropout and cycle threshold < 30 were submitted to high-throughput sequencing (HTS). 484 out of 1,557 participants tested positive for SARS-CoV-2. The S gene dropout was detected in 7.4% (36/484) and a peak was observed in August. The B.1.1.28, B.1.91 and B.1.1.33 lineages were circulating in early pandemic. The RBD novel mutation (Y380Q) was found in one sample occurring simultaneously with C379W and V395A, and the B.1.91 lineage in the spike protein. The Y380Q and C379W may interfere with the binding of neutralizing antibodies (CR3022, EY6A, H014, S304).

Children Have Similar Reverse Transcription Polymerase Chain Reaction Cycle Threshold for Severe Acute Respiratory Syndrome Coronavirus 2 in Comparison With Adults.

BACKGROUND: The viral dynamics and the role of children in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are not completely understood. Our aim was to evaluate reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (Ct) values among children with confirmed SARS-CoV-2 compared with that of adult subjects. METHODS: Patients (from 2 months to ≤18 years of age and adults) with signs and symptoms of acute SARS-CoV-2 infection for less than 7 days were prospectively enrolled in the study from May to November 2020. All participants performed RT-PCR assay for SARS-CoV-2 detection; Ct values of ORF1ab, N and S gene targets and the average of all the 3 probes were used as surrogates of viral load. RESULTS: There were 21 infants (2 months to <2 years), 40 children (≥2 to <12 years), 22 adolescents (≥12 to <18 years) and 293 adults of 376 participants with confirmed SARS-CoV-2 infections. RT-PCR Ct values from all participants less than 18 years of age, as well as from all childhood subgroups, were not significantly different from adults, comparing ORF1ab, N, S and all the gene targets together (P = 0.453). CONCLUSIONS: Ct values for children were comparable with that of adults. Although viral load is not the only determinant of SARS-CoV-2 transmission, children may play a role in the spread of coronavirus disease 2019 in the community.

Emerging arboviruses in Rio Grande do Sul, Brazil: chikungunya and zika outbreaks, 2014­2016

Questions investigated: The recent emergence of arboviruses such as Chikungunya virus (CHIKV) and Zika virus (ZIKV) in Brazil has posed a threat to human health and to the country's economy. Outbreaks occur mainly in tropical areas; however, increasing number of cases have been observed in Rio Grande do Sul (RS), the Southernmost state; therefore, surveillance of these arboviruses is essential for public health measures. Design: In this study, we analyzed 1276 samples from patients with clinically suspected arboviral diseases between 2014 and 2016. Demographic and clinical data were collected and described; cases of microcephaly associated with congenital infection were analyzed. Essential findings: Results show that CHIKV and ZIKV entered RS in 2014 and 2015, respectively, with imported cases confirmed. Autochthonous infections occurred in 2016 for both viruses, with a total of 5 autochthonous cases for CHIKV and 44 for ZIKV. Most patients were older than 21 years; the main symptoms were fever, arthralgia, myalgia, and headache; rash, conjunctivitis, and pruritus were also reported in ZIKV cases. Three cases of congenital Zika syndrome were confirmed in our study, while another 20 cases of microcephaly associated with congenital infection were confirmed (10 positive for syphilis, 6 for toxoplasmosis and 4 for cytomegalovirus). Main conclusions: Considering co­circulation of different arbovirus in RS, including Dengue virus, CHIKV, and ZIKV, and the presence of Aedes aegypti and Aedes albopictus in the area, surveillance of patients infected by these viruses contributes to the control and prevention of such diseases. Practical difficulties in diagnosing these infections are discussed. (AU)