SERO-EPIDEMIOLOGY OF SARS-COV2 INFECTION IN THE AUTONOMOUS CITY OF BUENOS AIRES

The pandemic of a new coronavirus SARS-COV-2, which causes COVID-19 disease, has spread rapidly and is a major public health challenge. While the focus is primarily on containing the number of cases and finding alternative therapies, information is still lacking to elucidate the dynamics of viral circulation and to understand the distribution of the infection in the population.

The cases reported in Argentina and worldwide could plausibly represent only a small proportion of the number of asymptomatic or poorly symptomatic cases that exist in society. However, the magnitude of this dissociation between symptomatic cases and asymptomatic persons is unknown.

Knowing this information is of strategic importance as it will allow the estimation of a community prevalence and the evaluation of the best containment strategy. In fact, although all social distancing measures are now indispensable, the feasibility of prolonging the measure over time is a complex issue and in any case will require population-based information.

The best way to approach the estimation of a true population prevalence is to take representative samples from the population and test them periodically. These experiences were carried out in other contexts showing heterogeneous results within the community studied. In Spain, for example, the range of antibodies present in the population varied from 1.1% to 14.2%, also showing that an important part of the population had had contact with the virus without symptoms. Studies in Switzerland and the United States also show similar findings. However, these estimates are not automatically transferable to other settings.

The city of Buenos Aires has a particular demographic composition with an important group of the population living in shantytowns (it is estimated that between 7% and 10% of the population lives in shantytowns) and with much heterogeneity among the different communes of the city. In the villas, the incidence rates of COVID-19 infection differ significantly from those present in the group "outside the village". However, there is also an important difference in the incidence rates by commune, even without considering the villas.

Thus, it is important to know the sero-epidemiology of antibodies against SARS-COV2 in a representative sample of the city of Buenos Aires.

For this purpose, a nationally produced test (COVIDAR IgG) developed by professionals from CONICET and Instituto Leloir will be used.

The aim of this initiative is to estimate the true dimension of the COVID-19 epidemic in the City of Buenos Aires, by studying the immunological status of the Buenos Aires population in relation to SARS-Cov2, as well as to observe the evolution of the infection among the population, since this information is essential to guide future public health measures related to the control of COVID-19.

To achieve this objective, a comprehensive sero-epidemiological study will be carried out to provide estimates of past SARS-Cov2 infection with sufficient precision to be representative of the sero-epidemiological status of the Buenos Aires city population.