Evaluation of SARS-CoV-2 infection and Coronavirus vaccine response in transplant recipients, dialysis patients, and health workers

Abstract

In 2019, a new Coronavirus (SARS-CoV-2) was reported in Wuhan Province, China, and soon proved to be a public health threatening pathogen, quickly acquiring a pandemic character (1). The unfavorable evolution of COVID-19 occurs as a result of an exuberant inflammatory response, initially affecting the lungs. In people with some alteration in the immune system, there is an overproduction of pro-inflammatory cytokines, resulting in structural pulmonary damage, systemic cytokine storm and multiple organ damage (4). Solid organ transplant recipients make prolonged use of immunosuppressive drugs with the aim of inhibiting the acquired immune response, especially the activity of T lymphocytes. In general, with mortality rates ranging from 20 to 30%, it being directly influenced by age and accumulation of comorbidities (5). A similar lethality is seen among chronic kidney patients on dialysis. In the Brazilian population, a registry including 37,852 dialysis patients from 24 of the 27 Brazilian states reported 1,291 confirmed cases and a fatality rate of 27.7% (6). In recently published international cohort studies of patients receiving pharmacological immunosuppression, including solid organ transplant recipients, they demonstrate low rates of seroconversion, low neutralizing antibody titers, and low proportion of cellular immunity development after complete regimens with two doses of SARS-CoV-2 vaccines (7; 8; 9). Among dialysis patients, cohort studies report intermediate rates of seroconversion after a complete vaccination course, but scarce data on clinical effectiveness (10). In view of this evidence, several countries, including Brazil, have been proposing the application of additional doses of vaccines for these groups of individuals. Brazil is the third country in the world in terms of numbers of patients on dialysis, with more than 133,000 patients on therapy, and has the second largest kidney transplant program in the world, with more than 50,000 patients currently under follow-up and an ascending curve of new cases of COVID-19 in the population. This makes Brazil a country with great potential to generate evidence on the clinical condition, the outcome of COVID-19 and the vaccine response in recipients of kidney transplantation and dialysis treatment. Another population at high risk of contagion by SARS-CoV-2 is composed of health professionals, essential workers defined as people who are paid or not, who work in health establishments, with potential for direct or indirect exposure to patients or infectious materials. An American study conducted between February and April 2020 showed that among the 315,531 cases of COVID-19 reported to the CDC, 9,982 (19%) were health professionals (11). In one study, screening with PCR was performed in health professionals from an institution, symptomatic or not, finding 3% positivity among those asymptomatic. The early identification and isolation of health professionals can contribute to the prevention of intra-hospital transmission between patients and other collaborators, and targeted prevention and control measures can reduce the risk of outbreaks associated with health care (12). In view of these issues that have not yet been elucidated, the present study was proposed so that the main clinical and immunological outcomes of SARS-CoV-2 infection and the vaccine response in different populations could be investigated. (AU)