Cross-protection and cross-neutralization capacity of ancestral and VOC-matched SARS-CoV-2 adenoviral vector-based vaccines.

COVID-19 vaccines were originally designed based on the ancestral Spike protein, but immune escape of emergent Variants of Concern (VOC) jeopardized their efficacy, warranting variant-proof vaccines. Here, we used preclinical rodent models to establish the cross-protective and cross-neutralizing capacity of adenoviral-vectored vaccines expressing VOC-matched Spike. CoroVaxG.3-D.FR, matched to Delta Plus Spike, displayed the highest levels of nAb to the matched VOC and mismatched variants. Cross-protection against viral infection in aged K18-hACE2 mice showed dramatic differences among the different vaccines. While Delta-targeted vaccines fully protected mice from a challenge with Gamma, a Gamma-based vaccine offered only partial protection to Delta challenge. Administration of CorovaxG.3-D.FR in a prime/boost regimen showed that a booster was able to increase the neutralizing capacity of the sera against all variants and fully protect aged K18-hACE2 mice against Omicron BA.1, as a BA.1-targeted vaccine did. The neutralizing capacity of the sera diminished in all cases against Omicron BA.2 and BA.5. Altogether, the data demonstrate that a booster with a vaccine based on an antigenically distant variant, such as Delta or BA.1, has the potential to protect from a wider range of SARS-CoV-2 lineages, although careful surveillance of breakthrough infections will help to evaluate combination vaccines targeting antigenically divergent variants yet to emerge.

Evaluation of RT-qPCR and Loop-Mediated Isothermal Amplification (LAMP) Assays for the Detection of SARS-CoV-2 in Argentina.

Our aim was to evaluate the analytical and clinical performance of the SARS-CoV-2 molecular detection kits used in Argentina. Nine real-time reverse-transcription polymerase chain reaction (RT-qPCR) and three reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assays were evaluated using the World Health Organization (WHO) recommended test as reference method. A secondary standard calibrated for the E, N and RdRp genes against the Pan American Health Organization-World Health Organization-International Standard was used to calculate the limit of detection (LoD). A panel of artificial clinical samples, 32 positive and 30 negative for SARS-CoV-2, were analyzed to estimate the kappa concordance (κ) and the diagnostic performance. Differences among the LoD values for the target genes amplified by each kit were >1 log copies/reaction. The κ for the RT-qPCR kits was greater than 0.9, whereas that for the RT-LAMP assays ranged from 0.75 to 0.93. The clinical performance of RT-qPCR kits showed 100% specificity and high sensitivity, although with variations according to the gene analyzed. The E and N genes provided greater clinical sensitivity, whereas the RdRp gene increased the clinical specificity. The RT-LAMP assays revealed a variable diagnostic performance. The information provided can be useful to choose the most appropriate diagnostic test and may contribute to the establishment of a consensus in the diagnosis of SARS-CoV-2 in Argentina and the region.

Development of a hyperimmune equine serum therapy for COVID-19 in Argentina.

The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab')2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.

La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab')2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.

Development of a hyperimmune equine serum therapy for COVID-19 in Argentina

The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab’)2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.

La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab’)2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.

Antigenic and genomic characterization of human influenza A and B viruses circulating in Argentina after the introduction of influenza A(H1N1)pdm09.

This study was conducted as part of the Argentinean Influenza and other Respiratory Viruses Surveillance Network, in the context of the Global Influenza Surveillance carried out by the World Health Organization (WHO). The objective was to study the activity and the antigenic and genomic characteristics of circulating viruses for three consecutive seasons (2010, 2011 and 2012) in order to investigate the emergence of influenza viral variants. During the study period, influenza virus circulation was detected from January to December. Influenza A and B, and all current subtypes of human influenza viruses, were present each year. Throughout the 2010 post-pandemic season, influenza A(H1N1)pdm09, unexpectedly, almost disappeared. The haemagglutinin (HA) of the A(H1N1)pdm09 viruses studied were segregated in a different genetic group to those identified during the 2009 pandemic, although they were still antigenically closely related to the vaccine strain A/California/07/2009. Influenza A(H3N2) viruses were the predominant strains circulating during the 2011 season, accounting for nearly 76 % of influenza viruses identified. That year, all HA sequences of the A(H3N2) viruses tested fell into the A/Victoria/208/2009 genetic clade, but remained antigenically related to A/Perth/16/2009 (reference vaccine recommended for this three-year period). A(H3N2) viruses isolated in 2012 were antigenically closely related to A/Victoria/361/2011, recommended by the WHO as the H3 component for the 2013 Southern Hemisphere formulation. B viruses belonging to the B/Victoria lineage circulated in 2010. A mixed circulation of viral variants of both B/Victoria and B/Yamagata lineages was detected in 2012, with the former being predominant. A(H1N1)pdm09 viruses remained antigenically closely related to the vaccine virus A/California/7/2009; A(H3N2) viruses continually evolved into new antigenic clusters and both B lineages, B/Victoria/2/87-like and B/Yamagata/16/88-like viruses, were observed during the study period. The virological surveillance showed that the majority of the circulating strains during the study period were antigenically related to the corresponding Southern Hemisphere vaccine strains except for the 2012 A(H3N2) viruses.

[Severe acute respiratory syndrome. The public health laboratory in a global emergency]. / Síndrome respiratorio agudo grave. El laboratorio de salud pública frente a una emergencia global.

By the end of year 2002 there was an outbreak of atypical pneumonia in Southeast Asia which soon spread to other continents. This new severe acute respiratory syndrome (SARS) was produced by a novel coronavirus. Due to the severity of the situation and risk of introduction of this pathology in our country, the need to arrange specific laboratory diagnostic tests arose. Classic techniques, such as the electron microscopy and molecular biology test such as retrotranscription followed by the polymerase chain reaction (RT-PCR) were implemented. The araldit included cells infected with bovine coronavirus which allowed the viral particles to be visualized easily but it took more time in comparison with the negative staining of free particles from viral cultures. RT-PCR was able to detect RNA of isolated viruses from cases in Hong Kong and Germany.

RSV molecular characterization and specific antibody response in young children with acute lower respiratory infection.

The presence of respiratory syncytial virus (RSV) in nasopharyngeal aspirates (NPA) were studied in 254 hospitalized Argentinean children with acute lower respiratory infection tract (ALRI). The specific humoral immune response and partial sequences of the G protein gene were studied in a subset of 22 children with RSV confirmed infection. The RSV IgM detection and the RSV IgG titration were made by immunofluorescence assay (IFA) in pairs of sera. The partial RSV G gene sequences were obtained by an RT-PCR amplification directly from de NPAs. RSV was present in 44.5% of the children. The RSV IgM was detected in 22.7 and 68.8% of the first and second sera, respectively. The IgG geometric mean titers of the acute and convalescent sera were 8 and 589. The RSV IgG titration was able to define 86.4% of the RSV confirmed cases. The percentage of coincidence between RSV IgM detection in the second sera and diagnosis by RSV IgG titration was 72.7% and no significant differences were observed. The nucleotide sequence of one group A and three group B viruses were identified. The first one was related with circulating viruses in Madrid, Montevideo and Mozambique during 1992, 1989 and 1999, respectively. The three sequences identified as group B viruses were closely related with circulating viruses in 1998 from South Africa and Canada during 1999 and 2000. The data obtained in our study provide the first approach at the molecular level (nucleotide) of the RSV circulating strains in Argentina and the lack of genotype patterns previously determined make necessary a continuous molecular surveillance in order to contribute to the understanding of the behavior of this virus in our community.

Estudio antigenico de cepas de influenza A (H3N2) circulantes en la Argentina Y su relacion con las cepas vacunales / Antigenic relationship between influenza A (H3N2) strains circulating in Argentina and vaccine strains

Debido a que los brotes anuales de influenza en Argentina ocurren comúnmente entre mayo y septiembre, la vacuna producida en el hemisferio norte para ser administrada en el mismo durante los meses de octubre y noviembre podría encontrarse desfasada para nuestro país. Con los fines de determinar si las cepas circulares en Argentina se encuentran relacionadas cercanamente desde el punto de vista antigénico con las cepas que integran las vacunas administradas, se las comparó con los virus de influenza A (H3N2) aislados entre mayo de 1994 y diciembre de 1997. Los especímenes clínicos (9866) utilizados fueron aspirados nasofaríngeos de niños hospitalizados con infección respiratoria aguda baja e hisopados nasofaríngeos de adultos con síndrome gripal. El diagnóstico de laboratorio inicial fue realizado por inmunofluorescencia, seguido por el intento de aislamiento viral en células MDCK. Se detectaron 242 virus de influenza A que fueron subtipificados antigénicamente pro inhibición de la hemaglutación (IHA) con el equipo de reactivos para influenza distribuido por la OMS. Una fracción de los virus detectados fue analizada antigénicamente por el Centro Colaborador de la OMS, Una facción de los virus detectados fue analizada antigénicamente por el Centro Colaborador de la OMS, que funciona en el CDC de Atlanta, Estados Unidos. Los virus de Influenza A (H3N2) caracterizados que circularon en Argentina na durante los últimos 4 años se correlacionaron parcialmente con los antígenos presentes en las vacunas administradas entre 1994 y 1997. Algunos años, estas variantes antigénicas circularon tardíamente (octubre de 1994 y de 1997). Las mismas iniciaron los brotes epidémicos de los años siguientes, fueron las prevalentes durante los mismos y estuvieron presentes dos años después en la fórmula vacunal administrada en el hemisferio sur. Los resultados de la IHA de nuestros aislamientos mostraron una elevada respuesta específica con los antisueros homólogos y una menos específica (16-64 veces menor) con los antidueros producidos contra las cepas vacunales. Esto nos demuestra la necesidad de intensificar la vigilância de influenza desde el laboratorio para tratar de formular la vacuna más apropiada.

Detección de una nueva variación genómica de Adenovirus 7 asociada a infecciones severas del tracto respiratorio inferior / Detection of a new genomic variation of Adenovirus 7 associated to severe infections of the lower respiratory tract

We report a new genomic variation of Adenovirus 7, associated to severe infections of the lower respiratory tract isolated during September 1990, from children under 3 years of age and living in Buenos Aires city. The restriction analysis with the BamHI, BglI, BglII and SmaI restriction endonucleases demonstrated that the new variation is highly related to the recently described Adenovirus 7h.