ABSTRACT
Recent studies have shown a temporal increase in the neutralizing antibody potency and breadth to SARS-CoV-2 variants in coronavirus disease 2019 (COVID-19) convalescent individuals. Here, we examined longitudinal antibody responses and viral neutralizing capacity to the B.1 lineage virus (Wuhan related), to variants of concern (VOC;Alpha, Beta, Gamma, and Delta), and to a local variant of interest (VOI;Lambda) in volunteers receiving the Sputnik V vaccine in Argentina. Longitudinal serum samples (N = 536) collected from 118 volunteers obtained between January and October 2021 were used. The analysis indicates that while anti-spike IgG levels significantly wane over time, the neutralizing capacity for the Wuhan-related lineages of SARS-CoV-2 and VOC is maintained within 6 months of vaccination. In addition, an improved antibody cross-neutralizing ability for circulating variants of concern (Beta and Gamma) was observed over time postvaccination. The viral variants that displayed higher escape to neutralizing antibodies with respect to the original virus (Beta and Gamma variants) were the ones showing the largest increase in susceptibility to neutralization over time after vaccination. Our observations indicate that serum neutralizing antibodies are maintained for at least 6 months and show a reduction of VOC escape to neutralizing antibodies over time after vaccination. IMPORTANCE Vaccines have been produced in record time for SARS-CoV-2, offering the possibility of halting the global pandemic However, inequalities in vaccine accessibility in different regions of the world create a need to increase international cooperation. Sputnik V is a recombinant adenovirus-based vaccine that has been widely used in Argentina and other developing countries, but limited information is available about its elicited immune responses. Here, we examined longitudinal antibody levels and viral neutralizing capacity elicited by Sputnik V vaccination. Using a cohort of 118 volunteers, we found that while anti-spike antibodies wane over time, the neutralizing capacity to viral variants of concern and local variants of interest is maintained within 4 months of vaccination. In addition, we observed an increased cross-neutralization activity over time for the Beta and Gamma variants. This study provides valuable information about the immune response generated by a vaccine platform used in many parts of the world.
ABSTRACT
The coronavirus disease 2019 (COVID-19) pandemic is devastating economies and healthcare systems worldwide and has caused near 5 million deaths. The Argentinean scientific community, gathered within the Coronavirus Unit created by the National Ministry of Science (MINCYT), quickly responded to the emergency by generating tools and information. In this context, the COVIDAR group was created at the Institute Leloir (March 2020) to develop a serologic test to evaluate the immune response against SARS-CoV-2. A versatile and robust ELISA test for detecting IgG and IgM antibodies against the whole spike protein was developed and produced. About 1.5 million tests were freely distributed to the public and private health institutions for evaluating immune responses in hospitalized patients, convalescent plasma programs and seroprevalence studies in neighborhoods, nursing homes, health care workers and others. Analysis of antibody levels and longitudinal studies of symptomatic and asymptomatic SARS-CoV-2 infections in thousands of patient samples provided insightful information about seroconversion time and antibody kinetics (Ojeda et al Plos Pat 2021). Studies of mild and severe COVID-19 cases that were discharged from hospitals or died, provided information regarding humoral responses and disease progression. While mass vaccination offers the possibility of halting the global pandemic, limitation in vaccine supply and inequalities in vaccine accessibility create a need to define local vaccination strategies. The COVIDAR group created a new laboratory (Serology and Vaccine Lab, SEVA-Lab) for cooperation programs and evaluating immune responses elicited by the vaccines applied in Argentina (Rossi et al Cell Reports Med, 2021). This Lab is also evaluating combined regimens of vaccines from different platforms, in a nation-wide program, and assessing the response to viral variants circulating in the region. A network of scientist from different areas of expertise, healthcare professionals from different hospitals and health authorities was created to evaluate the safety and immune response to heterologous vaccination regimens. This program generated information, tools and protocols in an unprecedented pace for policy making and defining vaccination strategies (https://doi.org/10.1101/2021.08.22.21262186). The pandemic forced us to create new ways to pursue science. As the experience of the COVIDAR group, briefly summarized here, there are a number of successful examples in our scientific community, which have shown that improving communication, implementing collaborative approaches and assembling transdisciplinary teams are essential for tackling complex public health problems.
ABSTRACT
Most countries in Latin America have already reported thousands of confirmed cases and vulnerable populations are the most affected by the coronavirus disease 2019 (COVID-19) pandemic. Preventive measures such as hygiene, social distancing, and isolation, essential to stop the spread of coronavirus, are difficult to accomplish for vulnerable populations due to their living conditions. Seroepidemiological surveys are assets to measure the transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Until July 1st, the incidence rate of SARS-CoV-2 infection in Barrio Padre Mugica, one of the largest slums in Buenos Aires City, was 5.9%. This study aimed to establish the prevalence of SARS-CoV-2 antibodies immunoglobulin G (IgG) immediately after the outbreak, and to identify neighbourhood, household and individual factors associated with seroconversion. The prevalence based on IgG was 53.4% (95% CI 52.8% to 54.1%). For each polymerase chain reaction (RT-qPCR) confirmed case, nine people tested IgG positive, indicating a high rate of undetected (probably asymptomatic) infections. Hence, the high rate of undiagnosed people suggests that clinical criteria and epidemiological nexus should be considered. The high seroprevalence observed in the context of an intense epidemic in a vulnerable area might serve as a reference to other countries. This study contributes to future decision making by understanding population immunity against SARS-CoV2 and its relation to living conditions and foccus that comprehensive biosocial, household-level interventions are needed.