Reinfection by SARS-CoV-2 by divergent Omicron sublineages, 16 days apart.

Since the beginning of the SARS-CoV-2 pandemic, studies on the variants and sublineages stand out, mainly in the cases of reinfection in a short period. In this study, we describe a case of infection by BA.1.1 sublineage in an individual from Southern Brazil. The same patient acquired reinfection with sublineage BA.2 within 16 days after the first detection. The viral extraction and RT-qPCR were performed on the samples LMM72045 (collected in May 2022) and LMM72044 (collected in June 2022). After the confirmation of SARS-CoV-2 infection, we conducted the sequencing and viral genome analysis. This case of reinfection affected a 52-year-old male patient, without comorbidities, with three doses of vaccines against COVID-19, showing symptoms on May 19. These symptoms lasted for approximately six days. The patient returned to work activities on May 30. However, on June 4, the patient felt a new round of clinical signs that lasted for approximately seven days. Analysis of the viral genomes recovered from patients' clinical samples revealed that the two COVID-19 episodes were related to two divergent VOC Omicron sublineages, namely, BA.1.1 for the first round of symptoms and BA.2 for the second infection. Based on our findings, we can say that the present case of reinfection is the shortest described so far.

Dynamics of nosocomial SARS-CoV-2 transmissions: Facing the challenge of variants of concern in a Brazilian reference hospital.

The hospital environment can be considered a high risk for the occurrence of SARS-CoV-2 transmission outbreaks, either for health professionals who are directly involved in the care of suspected or confirmed cases of the disease, or for patients, for being in an environment more vulnerable to the acquisition of nosocomial infections. In this molecular epidemiology study, we aimed to analyze the occurrence and transmission dynamics of SARS-CoV-2 in outbreaks and local chains of transmission in a large tertiary teaching hospital in southern Brazil, in addition to verifying circulating strains and their epidemiological relation in the local context, from September 21, 2020 to October 5, 2021. Positive samples involved in COVID-19 clusters or outbreaks were analyzed using clinical, epidemiological and genomic data. Different lineages and sublineages among patients in the same room were observed. Most patients had their first clinical manifestation, evidence of suspicion, and diagnostic confirmation within 7-14 days or >14 days after hospital admission. The patients who have contact with confirmed cases of COVID-19 spent, on average, 6.28 days in the same environment until the positive test. There was a significant association between the outcome and the number of vaccine doses (p < 0.05), where those who received two doses presented a lower occurrence of death. There was a total replacement of variant of concern (VOC) Gamma by VOC Delta from August 2021 at the study site. Although the epidemiological analysis indicates nosocomial infections, through genomic sequencing, it was established that most of the hospital outbreaks had different origins. These findings highlight the utility of integrating epidemiological and genomic data to identify possible routes of viral entry and dissemination.

Genomic and epidemiologic surveillance of SARS-CoV-2 in Southern Brazil and identification of a new Omicron-L452R sublineage.

Recently, SARS-CoV-2 Omicron variant (B.1.1.529) was first identified in Botswana in November 2021. In a short period of time, this highly mutated variant replaced the previous dominant Delta variant, causing an exponential increase in the number of COVID-19 cases, resulting in a new wave of pandemic. This current research article aims to analyze and summarize information about the genetic characteristics, amino acid mutations and epidemiological data providing scientific findings to enrich the SARS-CoV-2 knowledge. More importantly, we describe here, for the first time, the identification of a new Omicron variant of concern: Omicron-L452R in Brazil.

Viral isolation allows characterization of early samples of SARS-CoV-2 lineage B1.1.33 with unique mutations (S: H655Y and T63N) circulating in Southern Brazil in 2020.

Different approaches are in use to improve our knowledge about the causative agent of coronavirus disease (COVID-19). Cell culture-based methods are the better way to perform viral isolation, evaluate viral infectivity, and amplify the virus. Furthermore, next-generation sequencing (NGS) have been essential to analyze a complete genome and to describe new viral species and lineages that have arisen over time. Four naso-oropharyngeal swab samples, collected from April to July of 2020, were isolated and sequenced aiming to produce viral stocks and analyze the mutational profile of the found lineage. B.1.1.33 was the lineage detected in all sequences. Although the samples belong to the same lineage, it was possible to evaluate different mutations found including some that were first described in these sequences, like the S:H655Y and T63N. The results described here can help to elicit how the pandemic started to spread and how it has been evolving in south Brazil.

Early introduction, dispersal and evolution of Delta SARS-CoV-2 in Southern Brazil, late predominance of AY.99.2 and AY.101 related lineages.

The emergence of Variants of Concern (VOC) presenting an unusual number of new mutations is one of the most remarkable features of SARS-CoV-2. The Delta variant, since its appearance, replaced the VOC Gamma, which was responsible for the major COVID-19 wave in Brazil. In this study, we performed a Delta whole-genome sequencing of 183 samples as part of a major genomic surveillance study performed since the beginning of the pandemic. Here, we showed an emergence, widespread dispersion and consolidation of the Delta variant in Rio Grande do Sul State, completely replacing the Gamma variant in a four to five months period. Performing the phylogenetic and phylodynamic analysis, the majority of the sequences generated herein were classified as AY.99.2, AY.99.2-like and AY.101. AY.99.2 Delta-related lineage has been widely reported in Brazil and in the Americas as well. Altogether, our findings provided a mutational profile of the sequences and presented high substitutions per site in the root-to-tip phylogenetic tree, corroborating studies that show the high mutational rate of SARS-CoV-2 over time.

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).

Predominance of SARS-CoV-2 P.1 (Gamma) lineage inducing the recent COVID-19 wave in southern Brazil and the finding of an additional S: D614A mutation.

Recently, the highest wave of SARS-CoV-2 epidemic occurred since the beginning of the pandemic in Brazil was registered in Rio Grande do Sul (RS) State, Southern Brazil, considering the number of cases, deaths and hospitalization per day caused by COVID-19. In this study we described which lineages were circulating in the first quarter of 2021 in Southern Brazil to better understand the viral factors involved in the health crisis caused by SARS-CoV-2 in the region, searching also for possible additional SARS-CoV-2 sequence mutations. A total of 70 positive SARS-CoV-2 samples collected between January 28th, 2021 until April 23rd, 2021, were selected to sequencing. Whole genome sequencing of 70 SARS-CoV-2 samples showed a predominance of Gamma lineage (67%, 47/70), followed by P.2 lineage (27%, 19/70) and B.1.1.28 (6%, 4/70). Two Gamma lineage consensus sequences presented a new S:D614A mutation. Newly mutations could be emerging due the quick SARS-CoV-2 spreading. Thus, the greater understanding about immune protection and variants vigilance is essential to the better management of the health SARS-CoV-2 crisis.

Reinfection cases by closely related SARS-CoV-2 lineages in Southern Brazil.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the pandemic that started in late 2019 and still affects people's lives all over the world. Lack of protective immunity after primary infection has been involved with reported reinfection cases by SARS-CoV-2. In this study, we described two cases of reinfection caused by non-VOC (Variants of Concern) strains in southern Brazil, being one patient a healthcare worker. The four samples previously positive for SARS-CoV-2 by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) were sequenced by a high-performance platform and the genomic analysis confirmed that lineages responsible for infections were B.1.91 and B.1.1.33 (patient 1), and B.1.1.33 and B.1.1.28 (patient 2). The interval between the two positive RT-qPCR for patients 1 and 2 was 45 and 61 days, respectively. This data shows that patients may be reinfected even by very closely related SARS-CoV-2 lineages.

Detection of coronavirus in vampire bats (Desmodus rotundus) in southern Brazil.

The vampire bat (Desmodus rotundus) is a haematophagous animal that feeds exclusively on the blood of domestic mammals. Vampire bat feeding habits enable their contact with mammalian hosts and may enhance zoonotic spillover. Moreover, they may carry several pathogenic organisms, including coronaviruses (CoVs), for which they are important hosts. The human pathogens that cause severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV) and possibly coronavirus disease 2019 (SARS-CoV-2) all originated in bats but required bridge hosts to spread into human populations. To monitor the presence of potential zoonotic viruses in bats, the present work evaluated the presence of CoVs in vampire bats from southern Brazil. A total of 101 vampire bats were captured and euthanized between 2017 and 2019 in Rio Grande do Sul state, southern Brazil. The brain, heart, liver, lungs, kidneys and intestines were collected and macerated individually. The samples were pooled and submitted to high-throughput sequencing (HTS) using the Illumina MiSeq platform and subsequently individually screened using a pancoronavirus RT-PCR protocol. We detected CoV-related sequences in HTS, but only two (2/101; 1.98%) animals had CoV detected in the intestines by RT-PCR. Partial sequences of RdRp and spike genes were obtained in the same sample and the RdRp region in the other sample. The sequences were classified as belonging to Alphacoronavirus. The sequences were closely related to alphacoronaviruses detected in vampire bats from Peru. The continuous monitoring of bat CoVs may help to map and predict putative future zoonotic agents with great impacts on human health.