COVID-19

The Harvard T.H. Chan School of Public Health recommends a healthy diet, being physically active, managing psychological stress, and getting enough sleep.[170]

There is no good evidence that vitamin D status has any relationship with COVID-19 health outcomes.[171]

Hand-washing and hygiene

Thorough hand hygiene after any cough or sneeze is required.[172] The WHO also recommends that individuals wash hands often with soap and water for at least twenty seconds, especially after going to the toilet or when hands are visibly dirty, before eating and after blowing one's nose.[173] However, despite the measures recommended by the WHO, not all households have access to some basic necessities. In the Dominican Republic, 46% of households do not have access to safe drinking water. Only 44.9% receive drinking water at home every two to three days[132]. When soap and water are not available, the CDC recommends using an alcohol-based hand sanitiser with at least 60% alcohol.[174] For areas where commercial hand sanitisers are not readily available, the WHO provides two formulations for local production. In these formulations, the antimicrobial activity arises from ethanol or isopropanol. Hydrogen peroxide is used to help eliminate bacterial spores in the alcohol; it is "not an active substance for hand antisepsis." Glycerol is added as a humectant.[175]

Surface cleaning

After being expelled from the body, coronaviruses can survive on surfaces for hours to days. If a person touches the dirty surface, they may deposit the virus at the eyes, nose, or mouth where it can enter the body and cause infection.[18] Current evidence indicates that contact with infected surfaces is not the main driver of COVID-19,[176][177][178] leading to recommendations for optimised disinfection procedures to avoid issues such as the increase of antimicrobial resistance through the use of inappropriate cleaning products and processes.[179][180] Deep cleaning and other surface sanitation has been criticized as hygiene theater, giving a false sense of security against something primarily spread through the air.[181][182]

The amount of time that the virus can survive depends significantly on the type of surface, the temperature, and the humidity.[183] Coronaviruses die very quickly when exposed to the UV light in sunlight.[183] Like other enveloped viruses, SARS-CoV-2 survives longest when the temperature is at room temperature or lower, and when the relative humidity is low (<50%).[183]

On many surfaces, including as glass, some types of plastic, stainless steel, and skin, the virus can remain infective for several days indoors at room temperature, or even about a week under ideal conditions.[183] On some surfaces, including cotton fabric and copper, the virus usually dies after a few hours.[183] As a rule of thumb, the virus dies faster on porous surfaces than on non-porous surfaces.[183] However, this rule is not absolute, and of the many surfaces tested, two with the longest survival times are N95 respirator masks and surgical masks, both of which are considered porous surfaces.[183]

The CDC says that in most situations, cleaning surfaces with soap or detergant, not disinfecting, is enough to reduce risk of transmission.[184][185] The CDC recommends that if a COVID-19 case is suspected or confirmed at a facility such as an office or day care, all areas such as offices, bathrooms, common areas, shared electronic equipment like tablets, touch screens, keyboards, remote controls, and ATM machines used by the ill persons should be disinfected.[186] Surfaces may be decontaminated with 62–71 percent ethanol, 50–100 percent isopropanol, 0.1 percent sodium hypochlorite, 0.5 percent hydrogen peroxide, and 0.2–7.5 percent povidone-iodine. Other solutions, such as benzalkonium chloride and chlorhexidine gluconate, are less effective. Ultraviolet germicidal irradiation may also be used.[167] A datasheet comprising the authorised substances to disinfection in the food industry (including suspension or surface tested, kind of surface, use dilution, disinfectant and inocuylum volumes) can be seen in the supplementary material of.[179]

The severity of COVID-19 varies. The disease may take a mild course with few or no symptoms, resembling other common upper respiratory diseases such as the common cold. In 3–4% of cases (7.4% for those over age 65) symptoms are severe enough to cause hospitalization.[207] Mild cases typically recover within two weeks, while those with severe or critical diseases may take three to six weeks to recover. Among those who have died, the time from symptom onset to death has ranged from two to eight weeks.[62] The Italian Istituto Superiore di Sanità reported that the median time between the onset of symptoms and death was twelve days, with seven being hospitalised. However, people transferred to an ICU had a median time of ten days between hospitalisation and death.[208] Prolonged prothrombin time and elevated C-reactive protein levels on admission to the hospital are associated with severe course of COVID-19 and with a transfer to ICU.[209][210]

Some early studies suggest 10% to 20% of people with COVID-19 will experience symptoms lasting longer than a month.[211][212] A majority of those who were admitted to hospital with severe disease report long-term problems including fatigue and shortness of breath.[213] On 30 October 2020 WHO chief Tedros Adhanom warned that "to a significant number of people, the COVID virus poses a range of serious long-term effects." He has described the vast spectrum of COVID-19 symptoms that fluctuate over time as "really concerning". They range from fatigue, a cough and shortness of breath, to inflammation and injury of major organs – including the lungs and heart, and also neurological and psychologic effects. Symptoms often overlap and can affect any system in the body. Infected people have reported cyclical bouts of fatigue, headaches, months of complete exhaustion, mood swings, and other symptoms. Tedros has concluded that therefore herd immunity is "morally unconscionable and unfeasible".[214]

In terms of hospital readmissions about 9% of 106,000 individuals had to return for hospital treatment within two months of discharge. The average to readmit was eight days since first hospital visit. There are several risk factors that have been identified as being a cause of multiple admissions to a hospital facility. Among these are advanced age (above 65 years of age) and presence of a chronic condition such as diabetes, COPD, heart failure or chronic kidney disease.[215][216]

According to scientific reviews smokers are more likely to require intensive care or die compared to non-smokers,[217][218] air pollution is similarly associated with risk factors,[218] and pre-existing heart and lung diseases[219] and also obesity contributes to an increased health risk of COVID-19.[218][220][221]

It is also assumed that those that are immunocompromised are at higher risk of getting severely sick from SARS-CoV-2.[222] One research that looked into the COVID-19 infections in hospitalized kidney transplant recipients found a mortality rate of 11%.[223]

Genetics also plays an important role in the ability to fight off the disease. For instance, those that do not produce detectable type I interferons or produce auto-antibodies against these may get much sicker from COVID-19.[224][225] Genetic screening is able to detect interferon effector genes.[226]

Pregnant women may be at higher risk of severe COVID-19 infection based on data from other similar viruses, like SARS and MERS, but data for COVID-19 is lacking.