We are still learning about COVID-19 in every one of its aspects, there is not conclusive and uniform information about how symptoms of COVID-19 affect to our system, in fact, this disease progress differently depending on a wide range of factors and from one to another individual. Some other coronaviruses follow a similar progression in every patient; on the contrary, COVID-19 symptoms can come and go during the recovery period, which means that patient can report symptoms after they believe they are completely recovered.
In this sense, one of the problems we are facing at the moment is that general rules are hardly applied regarding contagion and transmission of SARS-CoV-2, due to the fact that there are noticeable differences on how it behaves in different individuals, which is why everyone needs to wear a mask and keep the physical distance as stablished for health organizations. However, we have available reliable information about the usual process Covid-19 follows in the human system.
As far as data have shown us until this moment, time from exposure to COVID-19 from the viral entry to the onset of symptoms is, on average, 5 to 6 days, and can range from 1 to 14 days according to WHO.
As symptoms can appear and disappear during those 14 days, the recommendation to people who have been exposed to the virus is that they must keep distance from others during the whole process in order to prevent the spread of the virus, especially when testing is not possible to corroborate the patient is not infected any longer.
As it is generally recognized, COVID-19 is a respiratory condition caused by a coronavirus. So far, data has revealed that most of the patients have mild symptoms and recover with no medical intervention, however, about 1 for every 6 have severe problems, as trouble breathing, and more serious symptoms appear more likely in elderly population and patients with previous health conditions as diabetes or heart diseases.
Some studies in the U.S and China revealed that the first symptom of covid-19 is usually a fever. According to WHO these are the most common symptoms identify in COVID-19 patients are fever, dry cough, and tiredness. Furthermore, there are some fewer common symptoms such as aches and pains, sore throat, diarrhea, conjunctivitis, headache, loss of taste or smell, skin rash, or discoloration of fingers or toes. Finally, there are some other serious symptoms detected in some several patients such as difficulty breathing or shortness of breath, chest pain or pressure and loss of speech or movement.
Once symptoms appear, some early signs will need to be treated more cautiously than others. World health organization warns about the importance of seeking immediate attention when identifying any of those serious symptoms. It is important as well to call before visiting any doctor or health facility as well.
According to the studies the first day of symptoms most of the people affected (88%) have also experienced fever and tiredness, some of them have also experience muscle pain and dry cough. According to recent data around 10% experience nausea or have diarrhea before the onset of the symptoms.
During the estimated period of 4 days the fever and the cough usually persists, and on day 5 it could appear breathing difficulty, specially if the patient has a preexisting disease related to this sign and the age of the person that is suffering from the infection. In this stage, most people can experience a recovery and the symptoms stop appearing, or they can also have these same symptoms intermittently during the whole process.
However, people who keep having serious symptoms on day 6 experience breathing difficulty, cough, and fever, followed by persistent chest pain or pressure, shortness of breath and bluish lips or face, which usually happened on day 7. According to the Chinese Center for Disease Control and Prevention, about 15% of patients infected with COVID-19 develop symptoms of acute respiratory distress syndrome.
On day 10 breathing difficulties can keep getting worse, and this will mean that that patient should be taken care of into an intensive unit in the hospital. For most people, fever usually ends on day 12, which is not the case of the cough that can last until later stages. For those who can survive the infection, signs stop appearing on day 13 to 14.
A person with COVID-19 may be contagious 48 to 72 hours before starting to experience symptoms. Emerging data suggest that people may actually be more likely to spread the virus during the 58 hours before the onset of symptoms. According to the Centers for Disease Control and Prevention, about 40% of coronaviruses cases are asymptomatic, which means even if they do not show signs of the disease they are infected with the virus. About 20% of symptomatic cases became severe or critical.
According to current data, the virus median incubation period is usually about 4 to five 5 days and during that time there is a high possibility that SARS-CoV-2 infected individuals do not know they are infected. Having into consideration that the virus can be transmitted during the pre-symptomatic phase, those persons who are asymptomatic and are not aware of their infection can spread the virus.
According to WHO laboratory data suggests that infected people appear to be most infectious just before they develop symptoms (namely 2 days before they develop symptoms) and early in their illness. People who develop severe disease can be infectious for longer.
Patients with no symptoms can test positive for COVID-19, in fact, according to recent surveys, most people whose results are positive in a diagnostic test are asymptomatic. That is the reason why health professionals ask for precaution, because although people might not have symptoms, they can spread the virus. Data suggest that 77% of people had no symptoms on the day they had the test performed, and around 86% did not have any other warning signs either.