Investigação de um surto de COVID-19 em uma instituição de longa permanência para idosos, em um município do sul do estado de Minas Gerais, Brasil

Abstract

COVID-19 is caused by SARS-CoV-2, a coronavirus that has infected 459.978.828 people, causing 6.047.190 deaths in the entire world as of 03/15/2022. Long-term care institutions for the elderly continue being places of concern. In Brazil, around 67% of deaths by COVID-19 happened to people older than 60 years. Considering the importance of understanding the COVID-19 disease in the elderly population, the present study aimed to investigate a COVID-19 outbreak in a long-term care institution for the elderly located in the south of the state of Minas Gerais. A cohort of 85 people, composed of 47 residents and 38 employees, was monitored during a COVID-19 outbreak. After identifying the index case, a documentary research was conducted to obtain information regarding health and vaccination status. Secretion collections with nasopharyngeal and/or oral swab to perform viral RNA search by RTqPCR were performed. Environmental samples were collected in common areas and of greater circulation to search for viral RNA. Patients positive for SARS-CoV-2 were isolated and had their contacts retested between 3 to 5 days. This procedure was repeated until all tested patients had negative results. A genomic surveillance to identify the variant responsible for the outbreak was conducted. Sanitary measures were immediately implemented, like the adequate use of equipment of individual protection by all employees. Of the 85 individuals monitored, 83 were completely vaccinated with the CoronaVac immunizer. In terms of the elderly residents, the percentage of infection was on the order of 97.8% (46/47). Of the 46 infected, only three (6.4%) were hospitalized and evolved to death as a consequence of COVID-19, and one subject, despite being infected, died of causes unrelated to the infection. With regard to the employees, seven (18.4%) were infected, five (13.1%) vaccinated and two (5.3%) unvaccinated. In the total cohort, 31 (58.4%) infected were asymptomatic and 22 (41.6%) symptomatic. The average age of the residents was 75.6 years and of the employees was 41.1 years. Age seems to be a determining factor in the vaccine protection against the infection of SARS-CoV-19. The responsible variant was identified as being the B1.1, whose sequence was deposited in GenBank. The environmental contamination was present in more than 70% of environments searched, with reduction of the viral presence after the implementation of disinfection measures. The present study demonstrates that elderly vaccinated and resident in long-term care institutions can be infected by SARS-CoV-2 and must be monitored. In the group analyzed, the efficiency of the CoronaVac vaccine in reducing complications, hospitalizations, and deaths in elderly was verified, being this protection even greater in younger patients, even in an extremely inhospitable environment, as the one in the present study. Additional studies must continue to be performed with the immunizers to better understand their benefits and potential, especially in patients in the group of risk.