Effectiveness and Adherence to Closed Face Shields to Prevent COVID-19 Transmission: A Randomized Controlled Trial

Introduction

According to the Johns Hopkins University coronavirus resource center, COVID-19 has caused more than 1,399,373 deaths globally (as of November 24, 2020), and more than 59 million cases have been reported worldwide. Governments have been forced to establish various preventive measures to control transmission in the communities. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted among close contacts mainly via respiratory droplets generated when an infected person coughs or sneezes. Likewise, airborne transmission through fomites/aerosols have been described due to the persistence of SARS-CoV-2 on different surfaces and the environment. SARS-CoV-2 causes the coronavirus disease 2019 (COVID-19), the respiratory illness responsible for the ongoing COVID-19 pandemic.

Physical distancing, face mask use, and eye protection had affected stopping SARS-CoV-2 transmission. While there is evidence of the use of face masks as a strategy to control respiratory infections and prevent the inhalation of large droplets and sprays, there is a need to determine the effectiveness of closed-face shields to prevent transmission in community settings. Despite the available reports, none of the randomized clinical trials have been conducted in the community setting. Although scarce, there is promising evidence showing that using face shields may bring an extra benefit in protecting airborne diseases, like COVID-19. Face shields have the benefits of preventing constant contact between face and hands, preventing airflow with possible infected particles from reaching the face, and protecting the eyes.

As of November 24, 2020, more than 1,254,979 cases have been reported in Colombia, and more than 35,479 deaths have occurred (a fatality rate of 2.83%). So far, no massive seroprevalence studies have been carried out in Colombia, that would determine the presence of Immunoglobulin G (IgG) and Immunoglobulin M (IgM) anti-SARS-CoV-2 antibodies, therefore, the level of immunity of the population and the likelihood of further waves of the disease. The first study to determine seroprevalence in Colombia found that, in a sample of 1368 people on the Caribbean coast of Colombia, 55.3% of the participants had anti-SARS-CoV-2 antibodies. The study of seroprevalence that is currently implemented by the Colombian National Institute of Health has not yet yielded results. Bogota, the country's capital district, has the highest number of confirmed cases compared to other departments and cities, but no studies have been conducted to determine what is level of immunity in the city´s population.

Therefore, epidemiological surveillance strategies are carried out to identify asymptomatic and symptomatic patients, trace contacts, and isolate cases to break transmission chains. As a result, an initiative called the CoVIDA project, which enrolls several institutions from academia to hospitals and the health authorities has emerged to support the epidemiological surveillance system of the city. This strategy is based on reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-Cov-2 detection in populations that, because of their work and high mobility in public places, are at high risk of infection and spread of the virus and has contributed to inform the health authorities and help them in the effective decision-making for public policy management.