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Annual vaccination against influenza is the best tool to prevent deaths and hospitalizations. Regular updates of trivalent inactivated influenza vaccines (TIV) are necessary due to high mutation rates in influenza viruses. TIV effectiveness is affected by antigenic mismatches, age, previous immunity, and other host factors. Studying TIV effectiveness annually in different populations is critical. The serological responses to Southern-Hemisphere TIV and circulating influenza strains were evaluated in 2018–2020 among Brazilian volunteers, using hemagglutination inhibition (HI) assays. Post-vaccination titers were corrected to account for pre-vaccination titers. Our population achieved >83% post-vaccination seroprotection levels, whereas seroconversion rates ranged from 10% to 46%. TIV significantly enhanced antibody titers and seroprotection against all prior and contemporary vaccine and circulating strains tested. Strong cross-reactive responses were detected, especially between H1N1 subtypes. A/Singapore/INFIMH-16-0019/2016, included in the 2018 TIV, induced the poorest response. Significant titer and seroprotection reductions were observed 6 and 12 months after vaccination. Age had a slight effect on TIV response, whereas previous vaccination was associated with lower seroconversion rates and titers. Despite this, TIV induced high seroprotection for all strains, in all groups. Regular TIV evaluations, based on regional influenza strain circulation, should be conducted and the factors affecting response studied. [ABSTRACT FROM AUTHOR]

Worldwide, infections by influenza viruses are considered a major public health challenge. In this study, influenza B vaccine mismatches and clinical aspects of Victoria and Yamagata infections in Brazil were assessed. Clinical samples were collected from patients suspected of influenza infection. In addition, sociodemographic, clinical, and epidemiological information were collected by the epidemiological surveillance teams. Influenza B lineages were determined by real-time RT-PCR and/or Sanger sequencing. In addition, putative phylogeny–trait associations were assessed by using the BaTS program after phylogenetic reconstruction by a Bayesian Markov Chain Monte Carlo method (BEAST software package). Over 2010–2020, B/Victoria and B/Yamagata-like lineages co-circulated in almost all seasonal epidemics, with B/Victoria predominance in most years. Vaccine mismatches between circulating viruses and the trivalent vaccine strains occurred in five of the eleven seasons (45.5%). No significant differences were identified in clinical presentation or disease severity caused by both strains, but subjects infected by B/Victoria-like viruses were significantly younger than their B/Yamagata-like counterparts (16.7 vs. 31.4 years, p < 0.001). This study contributes to a better understanding of the circulation patterns and clinical outcomes of B/Victoria- and B/Yamagata-like lineages in Brazil and advocate for the inclusion of a quadrivalent vaccine in the scope of the Brazilian National Immunization Program. [ABSTRACT FROM AUTHOR]

Background: During 2015–16 Brazil experienced the largest epidemic of Zika virus ever reported. This arthropod-borne virus (arbovirus) has been linked to Guillain-Barré syndrome (GBS) in adults but other neurological associations are uncertain. Chikungunya virus has caused outbreaks in Brazil since 2014 but associated neurological disease has rarely been reported here. We investigated adults with acute neurological disorders for Zika, chikungunya and dengue, another arbovirus circulating in Brazil. Methods: We studied adults who had developed a new neurological condition following suspected Zika virus infection between 1st November 2015 and 1st June 2016. Cerebrospinal fluid (CSF), serum, and urine were tested for evidence of Zika, chikungunya, and dengue viruses. Results: Of 35 patients studied, 22 had evidence of recent arboviral infection. Twelve had positive PCR or IgM for Zika, five of whom also had evidence for chikungunya, three for dengue, and one for all three viruses. Five of them presented with GBS; seven had presentations other than GBS, including meningoencephalitis, myelitis, radiculitis or combinations of these syndromes. Additionally, ten patients positive for chikungunya virus, two of whom also had evidence for dengue virus, presented with a similar range of neurological conditions. Conclusions: Zika virus is associated with a wide range of neurological manifestations, including central nervous system disease. Chikungunya virus appears to have an equally important association with neurological disease in Brazil, and many patients had dual infection. To understand fully the burden of Zika we must look beyond GBS, and also investigate for other co-circulating arboviruses, particularly chikungunya. [ABSTRACT FROM AUTHOR]

We report the characterization of a novel reassortant influenza A(H1N2) virus not previously reported in humans. Recovered from a a pig farm worker in southeast Brazil who had influenza-like illness, this virus is a triple reassortant containing gene segments from subtypes H1N2 (hemagglutinin), H3N2 (neuraminidase), and pandemic H1N1 (remaining genes). [ABSTRACT FROM AUTHOR]

Background: The objective of this study was to evaluate the association of SYNTAX scores I, II, and residual with cardiovascular outcomes of patients undergoing coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) and compare both procedures in a long-term follow-up.Methods: This is a retrospective single-center study from the MASS registry at the Heart Institute of the University of São Paulo, Brazil in which 969 patients with stable coronary artery disease undergoing CABG (559) or PCI (410) were included. We assessed the SYNTAX scores I, II and residual in both interventions. Clinical endpoints were the first occurrence of a composite of overall death, myocardial infarction, stroke, or repeat revascularization (MACCE) and the total occurrence of each component of MACCE.Results: In the CABG sample, SSI had a median of 23 (IQR 17-29.5), median SSII of 25.4 (IQR 19.2-32.8), and median rSS of 2 (IQR 0-6.5); in PCI SSI had a median of 14 (IQR 10-19.1), median SSII of 28.7 (IQR 23-34.2), and median rSS of 4.7 (IQR 0-9). Total of 174 events were documented and CABG patients had a lower rate of MACCE (15.6% vs. 21.2%; adjusted HR 1.98; 95% CI 1.13-3.47; P = 0.016) and repeat revascularization (3.8% vs. 11.5%; adjusted HR 4.35; CI 95% 1.74-10.85; P = 0.002) compared with PCI. No SYNTAX score tertile found a difference in death rate between procedures. In a multivariate analysis, the rSS was an independent predictor for MACCE (HR 1.04; 95% CI 1.01-1.06; P = 0.001). Regarding death, the only independent predictors were ejection fraction and renal function.Conclusion: Surgical revascularization resulted in a more complete revascularization and lower rates of major cardiac or cerebrovascular events in a long-term follow-up. Also, grading the incompleteness of revascularization through the residual SYNTAX score identified a higher event rate, suggesting that complete revascularization is associated with a better prognosis. [ABSTRACT FROM AUTHOR]

Neuraminidase inhibitors (NAIs) are the main class of antivirals currently used for the treatment of influenza infections. As influenza viruses are constantly evolving, drug-resistance can emerge resulting in reduced effectiveness of treatment. This study evaluated the presence of molecular markers associated with NAI susceptibility in 724 influenza A(H1N1)pdm09 positive samples from Brazilian surveillance system from the 2014–2016 seasons, including 76 isolates tested for oseltamivir (OST) susceptibility and 23 isolates also tested for zanamivir, peramivir and laninamivir susceptibility. We identified the H275Y (n = 3) and I223K (n = 1) NA substitutions, associated with reduced inhibition (RI) by the NAIs. Noteworthy, no epidemiological links were identified among the patients infected with the mutant viruses. Phylogenetic analysis from NA and hemagglutinin genes showed that mutant viruses were not clustered. All mutant virus strains carried the permissive substitutions V241I and N369K, in addition to the N386K, which has been shown to destabilize the NA structure. Functional NA analysis of one virus containing the H275Y mutation confirmed its highly RI profile to OST and peramivir and demonstrated that it had decreased viral replication and NA thermostability compared to the wild type virus. The remaining tested isolates presented normal inhibition profile to the NAIs tested. In conclusion, the overall frequency of influenza A(H1N1)pdm09 viruses bearing mutations associated with NAI RI was 0.6%, similar to what has been observed in recent global studies. [ABSTRACT FROM AUTHOR]

Pandemic influenza A H1N1 [A(H1N1)pdm09] was first detected in Brazil in May 2009, and spread extensively throughout the country causing a peak of infection during June to August 2009. Since then, it has continued to circulate with a seasonal pattern, causing high rates of morbidity and mortality. Over this period, the virus has continually evolved with the accumulation of new mutations. In this study we analyze the phylogenetic relationship in a collection of 220 A(H1N1)pdm09 hemagglutinin (HA) gene sequences collected during and after the pandemic period (2009 to 2014) in Brazil. In addition, we have looked for evidence of viral polymorphisms associated with severe disease and compared the range of viral variants with the vaccine strain (A/California/7/2009) used throughout this period. The phylogenetic analyses in this study revealed the circulation of at least eight genetic groups in Brazil. Two (G6-pdm and G7-pdm) co-circulated during the pandemic period, showing an early pattern of viral diversification with a low genetic distance from vaccine strain. Other phylogenetic groups, G5, G6 (including 6B, 6C and 6D subgroups), and G7 were found in the subsequent epidemic seasons from 2011 to 2014. These viruses exhibited more amino acid differences from the vaccine strain with several substitutions at the antigenic sites. This is associated with a theoretical decrease in the vaccine efficacy. Furthermore, we observed that the presence of any polymorphism at residue 222 of the HA gene was significantly associated with severe/fatal cases, reinforcing previous reports that described this residue as a potential virulence marker. This study provides new information about the circulation of some viral variants in Brazil, follows up potential genetic markers associated with virulence and allows infer if the efficacy of the current vaccine against more recent A(H1N1)pdm09 strains may be reduced. [ABSTRACT FROM AUTHOR]