Due to its leading role in fighting infections, the human immune system has been the focus of many studies in the context of Coronavirus disease 2019 (COVID-19). In a worldwide effort, the scientific community has transitioned from reporting about the effects of the novel coronavirus on the human body in the early days of the pandemic to exploring the body’s many immunopathological and immunoprotecting properties that have improved disease treatment and enabled the development of vaccines. The aim of this review is to explain what happens to the immune system after recovery from COVID-19 and/or vaccination against SARS-CoV-2, the virus that causes the disease. We detail the way in which the immune system responds to a SARS-CoV-2 infection, including innate and adaptive measures. Then, we describe the role of vaccination, the main types of COVID-19 vaccines and how they protect us. Further, we explain the reason why immunity after COVID-19 infection plus a vaccination appears to induce a stronger response compared with virus exposure alone. Additionally, this review reports some correlates of protection from SARS-CoV-2 infection. In conclusion, we reinforce that vaccination is safe and important in achieving herd immunity.

In this preliminary study we investigated cellular and humoral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood samples from 14 recovered coronavirus disease 2019 (COVID-19) patients and compared them ...

Coronavirus disease 19 (COVID-19) is caused by SARS-Cov-2 and the manifestations of this infection range from an absence of symptoms all the way up to severe disease leading to death. To estimate the prevalence of past infection in a population, the most readily available method is the detection of antibodies against the virus. This study has investigated the prevalence of anti-SARS-CoV-2 antibodies in outpatients of the Hospital das Clinicas, in Sao Paulo city (Brazil), which is a large university hospital belonging to the public health system that cares for patients with complex diseases who need tertiary or quaternary medical care. Our serological inquiry was carried out for 6 weeks, with once-a-week blood sampling and included 439 patients from several outpatient services. Overall, 61 patients tested positive for anti-SARS-CoV-2 IgG (13.9%); 56.1 % of the patients live in Sao Paulo city, with the remaining living in other towns of the metropolitan area; 32.8% of the patients testing positive for IgG antibodies to SARS-CoV-2 were asymptomatic, 55.7% developed mild or moderate disease and 11.5% had to be hospitalized. The prevalence of SARS-CoV-2 positive serology was lower among patients who had received the seasonal influenza vaccine compared to the ones who did not. These findings may indicate that those individuals care more about health issues, and/or that they have a better access to health care and/or a better quality of health care service. The large proportion of patients who were unaware of having had contact with SARS-CoV-2 deserves attention, reflecting the scarcity of tests performed in the population.

Objetivo: Discutir as recomendações de doação de leite materno aos Bancos de Leite Humano (BLH) frente à pandemia COVID-19. Metodologia: A pesquisa foi realizada envolvendo publicações sobre BLH, leite humano doado (LHD) e COVID-19 indexados nas bases de dados eletrônicas PubMed (US National Library of Medicine), Scientific Electronic Library Online Brasil (SciELO), Web of Science e Portal Capes. Os descritores que delimitaram a pesquisa foram: amamentação, aleitamento materno, BLH, LHD, leite humano, COVID-19, pandemia e Sars-CoV-2 em português e inglês. Resultados e discussão: Como o vírus da COVID-19 é transmitido por gotículas respiratórias e o vírus sobrevive por períodos variados em superfícies inanimadas, neste trabalho observamos as principais medidas de controle de transmissão do vírus pelo LHD durante todo o processo de coleta, processamento e distribuição do leite humano até os recém-nascidos das Unidades de Terapia Intensiva Neonatal (UTIN). É necessário controle de qualidade com alto rigor higiênico-sanitário do LHD como esterilização dos materiais que entrarem em contato com o leite materno, higienização do ambiente onde será realizada a ordenha, utilização de gorro e máscara, lavagem das mãos com água e sabão e eliminação dos primeiros jatos de leite ordenhado. Conclusão: As doadoras de leite humano ordenhado devem realizar uma triagem nos BLH para avaliação e orientações antes de iniciar a doação de leite humano, a fim de evitar a transmissão do vírus da COVID-19 durante todo o processo de coleta, processamento e distribuição do leite humano até os recém-nascidos das UTIN.

Therapeutic vaccines based on monocyte‐derived dendritic cells have been shown to be promising strategies and may act as complementary treatments for viral infections, cancers, and, more recently, autoimmune diseases. Alpha‐type‐1‐polarized dendritic cells (aDC1s) have been shown to induce type‐1 immunity with a high capacity to produce interleukin‐12p70 (IL‐12p70). In the clinical use of cell‐based therapeutics, injectable solutions can affect the morphology, immunophenotypic profile, and viability of cells before delivery and their survival after injection. In this sense, preparing a cell suspension that maintains the quality of aDC1s is essential to ensure effective immunotherapy. In the present study, monocytes were differentiated into aDC1s in the presence of IL‐4 and GM‐CSF. On day 5, the cells were matured by the addition of a cytokine cocktail consisting of IFN‐α, IFN‐γ, IL‐1β, TNF‐α, and Poly I:C. After 48 hr, mature aDC1s were harvested and suspended in two different solutions: normal saline and Ringer’s lactate. The maintenance of cells in suspension was evaluated after 4, 6, and 8 hr of storage. Cell viability, immunophenotyping, and apoptosis analyses were performed by flow cytometry. Cellular morphology was observed by electron microscopy, and the production of IL‐12p70 by aDC1s was evaluated by ELISA. Compared with normal saline, Ringer’s lactate solution was more effective at maintaining DC viability for up to 8 hr of incubation at 4 or 22°C.