The coronavirus disease 2019 (COVID-19) is an illness resulting from the SARS-CoV-2 virus. The experience of this illness is different for everyone; some individuals may show no signs of sickness, while for others, it can become a serious condition. The progression from initial viral contact to potential long-term health issues follows a general timeline, though individual experiences can differ significantly.
Incubation and Initial Onset
The time from exposure to the SARS-CoV-2 virus to the start of symptoms is called the incubation period. Symptoms begin to show up about 5 to 6 days after a person is infected, but this can range from 2 to 14 days. Newer variants of the virus have sometimes been associated with shorter incubation periods. During this time, the virus is actively multiplying within the body, primarily targeting the respiratory system.
The first indication of illness is often a fever. Following the fever, a person may experience a dry cough, profound fatigue, and body aches. Another distinctive early sign for some has been the sudden loss of taste or smell, though this has become less common with more recent viral variants. These initial symptoms signal that the body’s immune system has started to respond.
The First Week of Symptoms
During the first week of a COVID-19 infection, an individual’s symptoms can evolve. For many, the illness remains mild to moderate during this period. Initial symptoms like fever and fatigue might continue, and new ones can emerge, such as a sore throat, headache, muscle pain, or a stuffy or runny nose.
Some people may also experience gastrointestinal issues, such as nausea or diarrhea. Toward the end of this first week, many individuals with mild cases start to see their symptoms lessen and begin a gradual recovery. It is during these initial days that an infected person is most likely to transmit the virus to others.
The Critical Turning Point
For a majority of individuals, symptoms may start to improve after the first week. However, a subset of patients enters a more difficult phase of the illness around days 7 to 12. This period represents a turning point where the illness can suddenly become more severe due to the body’s own immune response becoming excessively aggressive.
The most prominent warning sign during this time is the development or worsening of shortness of breath, medically known as dyspnea. This can be accompanied by persistent pain or pressure in the chest, new confusion, or a bluish tint to the lips or face, which indicates a lack of oxygen. These symptoms are indicators that the lungs are becoming inflamed and struggling to function.
This deterioration is often attributed to a “cytokine storm.” In this process, the immune system releases an overwhelming flood of inflammatory proteins called cytokines. While these are meant to fight the infection, their excessive production leads to widespread inflammation and can cause severe damage to the lungs, preventing oxygen from moving into the bloodstream.
Severe Disease and Hospitalization
When an illness progresses past the critical turning point, it is considered severe COVID-19, characterized by significant respiratory complications that require hospital care. The extensive inflammation in the lungs can lead to pneumonia, an infection that inflames the air sacs in the lungs, which may fill with fluid.
In the most serious cases, this can progress to Acute Respiratory Distress Syndrome (ARDS), a form of lung failure where the lungs cannot provide the body’s organs with enough oxygen. The primary goal of hospital care is to manage low blood oxygen levels, a condition known as hypoxia.
To address hypoxia, patients are often given supplemental oxygen. Doctors may also administer corticosteroids, medications that help reduce the severe inflammation driving the lung damage. For patients who are unable to breathe sufficiently on their own, mechanical ventilation may be required.
Recovery and the Post-Acute Phase
The path to recovery from COVID-19 varies depending on the severity of the illness. For those with mild cases, symptoms usually resolve within about two weeks. For individuals who experienced severe disease, the recovery process can be much longer, sometimes needing weeks or months to regain strength and lung function.
Even after the initial infection has cleared, some individuals continue to experience symptoms in the post-acute phase of COVID-19, often referred to as “Long COVID.” This condition can affect anyone who has had COVID-19, regardless of how mild or severe their initial illness was.
Lingering symptoms can be wide-ranging. The most common include ongoing fatigue, shortness of breath, and cognitive issues described as “brain fog.” Other long-term symptoms can include:
- Persistent cough
- Muscle pain
- Headaches
- Loss of taste or smell that can last for weeks or months