DETECÇÃO DE ANTICORPOS NEUTRALIZANTES CONTRA AS VARIANTES DELTA, GAMA E OMICRON APÓS IMUNIZAÇÃO POR CORONAVAC E BOOSTER COM PFIZER

Introdução A vacinação é uma ferramenta essencial para o controle da infecção por SARS-CoV-2 e da pandemia de COVID-19. O surgimento de novas variantes genéticas do vírus SARS-CoV-2 nos trouxe a questão se há diferencial capacidade neutralizante dos anticorpos quanto às variantes de preocupação (VOCs). Objetivo Nosso estudo se dirigiu a avaliar a capacidade neutralizante dos anticorpos de indivíduos imunizados com a vacina CoronaVac e dose de reforço com Pfizer contra as variantes Gama, Delta e Omicron. Método Amostras de soro foram obtidas de 41 profissionais da saúde da Faculdade de Medicina da USP, sem infecção prévia por SARS-CoV-2 no esquema vacinal CoronaVac (2 doses) seguido de dose booster com vacina Pfizer. Os níveis de anticorpos neutralizantes para as variantes Gama, Delta e Omicron foram avaliados 32 e 186 dias após a segunda dose da vacina. Também avaliamos a atividade neutralizante dos anticorpos contra a variante Omicron em 39 dos indivíduos após 62 dias de imunização de reforço, com a vacina Pfizer. Os títulos de anticorpos foram obtidos pelo Teste de Neutralização Viral (VNT) e observação de efeito citopático. Resultados A neutralização por anticorpos contra as variantes Gama, Delta e Omicron foi de 78%, 65.9% e 58.5% respectivamente, após uma média de 32 dias após a segunda dose por CoronaVac. Houve uma diminuição na frequência de anticorpos neutralizantes para 17.1%, 24.4% e 2.4% contra as variantes Gama, Delta e Omicron, respectivamente, após, em média 186 dias das duas doses da vacina CoronaVac. A dose booster com a vacina Pfizer foi capaz de induzir a produção de anticorpos neutralizantes contra a variante Omicron em 87.2% dos indivíduos avaliados. Conclusão Os indivíduos vacinados com CoronaVac apresentaram uma queda nítida de anticorpos neutralizantes contra as 3 variantes de SARS-CoV-2 analisadas após 186 dias da imunização por 2 doses. A dose de reforço com Pfizer induziu a produção de anticorpos neutralizantes contra a variante Omicron na maior parte dos indivíduos avaliados (87.2%), 60 dias após imunização. Não houve diferença significativa na frequência de anticorpos neutralizantes entre as variantes analisadas.

SARS-CoV-2 aerosol generation during respiratory equipment reprocessing.

Aerosolization may occur during reprocessing of medical devices. With the current coronavirus disease 2019 pandemic, it is important to understand the necessity of using respirators in the cleaning area of the sterile processing department. To evaluate the presence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in the air of the sterile processing department during the reprocessing of contaminated medical devices. Air and surface samples were collected from the sterile processing department of two teaching tertiary hospitals during the reprocessing of respiratory equipment used in patients diagnosed with coronavirus disease 2019 and from intensive care units during treatment of these patients. SARS-CoV-2 was detected only in 1 air sample before the beginning of decontamination process. Viable severe acute respiratory syndrome coronavirus 2 RNA was not detected in any sample collected from around symptomatic patients or in sterile processing department samples. The cleaning of respiratory equipment does not cause aerosolization of SARS-CoV-2. We believe that the use of medical masks is sufficient while reprocessing medical devices during the coronavirus disease 2019 pandemic.

Nucleoprotein-based ELISA for detection of SARS-COV-2 IgG antibodies: Could an old assay be suitable for serodiagnosis of the new coronavirus?

OBJECTIVES: We evaluated the performance of a nucleoprotein-based enzyme-linked immunosorbent assay (ELISA) for detection of IgG antibodies to SARS-CoV-2. METHODS: The ELISA was based on serum IgG reactivity to a 46-kDa protein derived from the recombinant SARS-CoV2 nucleoprotein. Assay sensitivity was assessed using serum samples from 134 COVID-19 confirmed cases obtained > 15 days after symptom onset. Specificity was determined by testing sera from 94 healthy controls. Cross-reactivity was evaluated with sera from 96 individuals with previous dengue or zika virus-confirmed infections, with 44 sera from individuals with confirmed infections to other respiratory viruses or with bacterial and fungal infections that cause pneumonia and with 40 sera negative for SARS-CoV-2 nucleoprotein by commercial ELISA kits. RESULTS: The majority of subjects were male and ≥ 60 years old. Assay sensitivity was 90.3 % (95 % confidence interval 84.1 %-94.2 %) and specificity was 97.9 % (92.6 %-99.4 %). There was no cross-reactivity with sera from individuals diagnosed with dengue, zika virus, influenza virus, rhinovirus, adenovirus, respiratory syncytial virus, seasonal coronavirus, Mycobacterium tuberculosis, Staphylococcus (S. aureus and coagulase-negative), Streptococcus pneumoniae, Klebsiella pneumoniae and the fungus Aspergillus fumigatus. The level of concordance of our test with results from commercial ELISA kits was 100 %. CONCLUSION: The nucleoprotein-based ELISA was specific for detection of IgG anti-nucleoprotein antibodies to SARS-CoV-2. It utilizes a frequently employed low expense assay protocol and is easier to perform than other currently available commercial SARS-CoV2 antibody detection tests.