ABSTRACT
The first documented cases of Coronavirus disease of 2019 (COVID-19) in Wuhan city (Hubei province, China) were caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), studies mention viral transmission is more common in indoor and poorly ventilated environments compared to outdoor environments or environments with abundant airflow. In this context, this research aimed to estimate, through a mathematical model by a Box-Behnken design, the time and occupancy required in a physical space to reach CO2 levels that exceed the risk level established as a safer condition of 700 ppm for SARS-CoV-2 transmission. According to the proposed mathematical model, it is possible to predict safe conditions. With this, it was found that natural ventilation is the best option to reduce CO2 concentration, considering the occupancy/m3 and time, allowing a constant airflow;the use of air conditioners to control the temperature in rooms without natural ventilation is suggested;notwithstanding, these types of equipment are not designed to reduce CO2 concentration. Thus, their use in rooms with open windows and doors leads to a shorter equipment lifetime, for this reason, its operation in special conditions, such as in rooms without natural ventilation should be considered
ABSTRACT
COVID-19 is a worldwide health emergency, therapy for this disease is based on antiviral drugs and immunomodulators, however, there is no treatment to effectively reduce the COVID-19 mortality rate. Fucoidan is a polysaccharide obtained from marine brown algae, with anti-inflammatory, antiviral, and immune-enhancing properties, thus, fucoidan may be used as an alternative treatment (complementary to prescribed medical therapy) for the recovery of COVID-19. This work aimed to determine the effects of ex-vivo treatment with fucoidan on cytotoxicity, apoptosis, necrosis, and senescence, besides functional parameters of calcium flux and mitochondrial membrane potential (ΔΨm) on human peripheral blood mononuclear cells isolated from SARS-CoV-2 infected, recovered and healthy subjects. Data suggest that fucoidan does not exert cytotoxicity or senescence, however, it induces the increment of intracellular calcium flux. Additionally, fucoidan promotes recovery of ΔΨm in PBMCs from COVID-19 recovered females. Data suggest that fucoidan could ameliorate the immune response in COVID-19 patients.