Since 1999 the World Health Organization issues annually an additional influenza vaccine composition recommendation. This initiative aimed to extend to the Southern Hemisphere (SH) the benefits—previously enjoyed only by the Northern Hemisphere (NH)—of a vaccine recommendation issued as close as possible to the moment just before the onset of the influenza epidemic season. A short time between the issue of the recommendation and vaccine delivery is needed to maximize the chances of correct matching between putative circulating strains and one of the three strains present in the vaccine composition. Here we compare the effectiveness of the SH influenza vaccination adopted in Brazil with hypothetical alternative scenarios defined by different timings of vaccine delivery and/or composition. Scores were based on the temporal overlap between vaccine-induced protection and circulating strains. Viral data were obtained between 1999 and 2007 from constant surveillance and strain characterization in two Brazilian cities: Belém, located at the Equatorial region, and São Paulo, at the limit between the tropical and subtropical regions. Our results show that, among currently feasible options, the best strategy for Brazil would be to adopt the NH composition and timing, as in such case protection would increase from 30% to 65% (p<.01) if past data can be used as a prediction of the future. The influenza season starts in Brazil (and in the equator virtually ends) well before the SH winter, making the current delivery of the SH vaccination in April too late to be effective. Since Brazil encompasses a large area of the Southern Hemisphere, our results point to the possibility of these conclusions being similarly valid for other tropical regions.

Respiratory syncytial virus (RSV) is the most common cause of severe respiratory infections worldwide, and an important cause of childhood bronchiolitis, pneumonia and mortality. Although prevention of RSV infection by immunoprophylaxis with palivizumab has proved effective, a precise understanding of the timing of RSV outbreaks is necessary to ensure that infants are protected when RSV is circulating. In this study a consistent shift in the seasonal patterns of RSV circulation in southeast Brazil (Sao Paulo) is reported based on the analysis of 15 years of viral surveillance. Surveillance was conducted from 1996 to 2010 and involved the collection of samples from children with symptoms of acute respiratory infection. Putative changes in school terms, in the proportion of RSV genotypes infecting children and in the seasonal dynamics of several climatic parameters during the period were also investigated. The results revealed a progression in the timing of RSV seasons, with a shift in the onset and peak of RSV epidemics from 2007 onwards. Although lower rainfall and temperatures were associated with the onset of outbreaks, there was no evidence of changes in climate, school terms or in the relative proportion of genotypes in the period analyzed. These findings have direct implications for improving the prophylactic use of palivizumab, and stress the importance of fine tuning prophylaxis with recent surveillance data. In the case of Sao Paulo, palivizumab prophylaxis should be initiated earlier than suggested currently. Similar adjustments may be necessary in other regions.

Compared to previous years, seasonal influenza activity commenced early in São Paulo State, Brazil, Southern hemisphere during the 2016 year. In order to investigate the genetic pattern of influenza A(H1N1)pdm09 in the State of Sao Paulo a total of 479 respiratory samples, collected in January by Sentinel Surveillance Units, were screened by real-time RT-PCR. A total of 6 Influenza viruses A(H1N1)pdm09 presenting ct values ≤ 30 were sequenced following phylogenetic analysis. The present study identified the circulation of the new 6B.1 subgroup (A/Sao Paulo/10-118/2016 and A/Sao Paulo/3032/2016). In addition, influenza A(H1N1)pdm09 group 6B has also been identified during January in the State of Sao Paulo. Despite amino acid changes and changes in potential glycosylation motifs, 6B.1 viruses were well inhibited by the reference ferret antiserum against A/California/07/2009 virus, the A(H1N1)pdm09 component of the vaccine for the 2016 influenza season.

Background: Surveillance of COVID infection and isolation of infected individuals is one of the available tools to control the spread of SAR-CoV-2. Asymptomatic and pre symptomatic are responsible for substantial transmission. RNA or antigen tests are necessary to identify non-symptomatic individuals. We tested the feasibility of using samples pooling offering different collection alternatives (swab/throat wash/saliva) to volunteers of a public health institute. Methods: We evaluated pool samples from both reconstituted (frozen material from tested samples) and a prospective collection of asymptomatic volunteers. Some collections were paired for comparison. Pooled and some individual samples were extracted with QIAamp Viral RNA Mini Kit (Qiagen, USA) and/or Lucigen Quick Extract DNA extraction solution (BioSearch, USA) and submitted to rtCCR using (Allplex, Seegene, Korea). Results: A total of 240 samples from 130 new collections and 37 samples with known result were evaluated. Pool CT was generally higher than individual samples. Lucigen extraction showed higher CT, including false negative results for samples with high CT at Qiagen extraction. Paired Swab and TW samples showed comparable results. No volunteer from negative pools reported any symptom in the 2-3 days after collection. Conclusions: Clinical samples pooling to detect SARS-CoV-2 RNA is feasible and an economical way to test for COVID-19, especially in surveillance strategies targeting more infectiousness, higher viremia individuals. The use of Lucigen reagents show lower sensibility that may lead to false negative results with lower viremia samples. Combining throat wash with saliva may provide and interesting alternative for auto collection, but more comparative work is needed.