Institutional outbreaks of influenza-like illnesses in the state of São Paulo: an analysis of the epidemiological profile during the COVID-19 pandemic.

OBJECTIVES: This study aimed to spatiotemporally analyze the profile of influenza-like illness (ILI) outbreaks in the state of São Paulo, Brazil, between 2020 and 2022. STUDY DESIGN: This was a cross-sectional retrospective study. METHODS: Outbreaks of ILI with final diagnoses of COVID-19, influenza, or other respiratory viruses (ORVs) recorded between January 2020 and November 2022, obtained from the Notifiable Diseases Information System (SINAN NET) Outbreak module, were analyzed. Kernel density estimates and Getis-Ord Gi∗ statistics were performed to identify spatial clusters. RESULTS: A total of 13,314 ILI outbreaks were identified, involving 130,568 cases and 2649 deaths. Of these, 104,399 (80%) were confirmed as COVID-19, 15,861 (12%) were confirmed as ORV, and 10,308 (8%) were confirmed as influenza. The year 2021 had the highest number of outbreaks and cases. Schools recorded the most outbreaks and cases, followed by long-term care facilities for older adults (LTCs). The highest average number of cases per outbreak and the highest attack rates occurred at social gatherings and prisons. Prisoners were three times more likely to contract COVID-19 during outbreaks than people in other institutions. The highest hospitalization and mortality rates for all virus types occurred in the LTC group. The occurrence and intensity of outbreaks were highly heterogeneous among the different institutions after the introduction of new SARS-CoV-2 variants in the state. CONCLUSIONS: ILI outbreaks were not randomly distributed; they clustered in specific areas. Transmissibility varied among different institutions with different responses to the COVID-19 pandemic. These results can be used as a basis for prioritizing actions and allocating resources during future pandemics.

Evolutionary pattern of reemerging influenza B/Victoria lineage viruses in São Paulo, Brazil, 1996-2012: Implications for vaccine composition strategy.

Since the 1980s, 2 antigenically distinct influenza B lineages have cocirculated in the world: B/Victoria/2/87 (first appeared in the 1980s) and B/Yamagata/16/88 (became predominant in the 1990s). B/Victoria/2/87 isolates were geographically restricted to eastern Asia during 1991-2000. During 2000-2001 and 2001-2002, B/Victoria/2/87 isolates reemerged in North America, Europe, and South America, and then spread globally. During influenza virus surveillance, season 2002, an outbreak of acute respiratory illness, which quickly spread among the population, has been notified by public health authorities living in Araraquara, São Paulo, Brazil. Instituto Adolfo Lutz and Secretariat of Health of São Paulo state teams initiate an investigation towards to describe the pattern of infection in this population temporally and by age and to characterize the strains by virus isolation and hemagglutination inhibition assay. The outbreak lasted approximately 10 weeks; many cases occurred between mid-August and mid-September. Children younger than 13 years were the most affected; the elderly were mostly immune to infection. Analysis of the clinical respiratory samples helped in identifying the B/Hong Kong/330/2001 and B/Brisbane/32/2002 subtypes-recent variants of B/Victoria/02/88, a lineage restricted to Southeast Asia until 2001. The Araraquara outbreak confirms the reemergence of the B/Victoria viruses in South America and highlights the importance of monitoring local circulating strains, especially in light of the absence of cross-protection between antigenically distinct influenza lineages. Based on influenza virus surveillance, public health authorities worldwide should decide whether trivalent vaccines or quadrivalent vaccines (containing both influenza virus B lineages) are to be used in each country.

Surto de Doença Meningocócica no Município de Estrela D’Oeste, SP, Setembro de 2006: da / investigação ao controle / Meningitis Outbreak in the city of Estrela D’Oeste/SP, September, 2006: from investigation to

A doença meningocócica (DM) é uma moléstia infecciosa aguda de expressiva relevância em saúde pública, devido ao seu potencial epidêmico, a elevada morbi-mortalidade e ao percentual significativo de seqüelas. Em setembro de 2006, o Município de Estrela D’Oeste/São Paulo confirmou a ocorrência de 3 casos de DM e letalidade de 66,7%. Os casos foram sorogrupados e todos identificados como meningococo do sorogrupo C. O objetivo da investigação foi caracterizar e confirmar a ocorrência do surto da doença na região. A investigação dos casos foi realizada a partir da análise de bancos de dados, de fichas epidemiológicas de notificação/investigação, de fichas de atendimento hospitalar e dos exames processados e de entrevistas com os médicos, casos suspeitos, contatos e familiares. Para inclusão no presente surto foram utilizadas as seguintes definições de casos: caso suspeito: todo paciente com sinais e/ou sintomas de meningite aguda, isto é, febre alta, vômitos, cefaléia intensa, rigidez de nuca ou abaulamento de fontanela; com ou sem toxemia (sonolência e/ou torpor e/ou irritação) e lesões cutâneas (petéquias ou púrpuras) residente ou que se deslocou para o Município de Estrela D’Oeste, no mês de setembro de 2006. Caso confirmado: caso suspeito com critério de confirmação laboratorial e/ou necropsia. Na ocasião, foi confirmado um surto de DM no Município de Estrela D’Oeste, com três casos e dois óbitos, desenvolvido em curso rápido e progressivo e com identificação do meningococo sorogrupo C nos três casos, o que está de acordo com a atual prevalência do sorogrupo C no Estado de São Paulo. As medidas de controle, quimioprofilaxia e vacinação, foram realizadas de forma criteriosa e oportuna. A investigação permitiu a descrição clínica e epidemiológica dos casos, com a confirmação de surto e a efetivação oportuna das ações de prevenção e controle.