COVID-19 illness seems to follow a fairly predictable course, though people experience the illness differently. People who are infected with SARS – Co-V2 may only go through the first phase, or they may only go through the first two phases, or they may go through phase 1,2 and 4 and skip the third phase. Finally, people can go straight through from phases 1-4. There are also cases of people who have had long periods of remission between the second phase and the third – and investigations are happening to determine how many people are reinfected as opposed to having a flare later in the course of their infection. This is determined by genetic testing and there is at least one known case where two different strains of the virus infected one person resulting in two different courses of COVID-19.
In the first phase people are spreading virus (infectious) but not ill and the virus is replicating inside them. ( From contact to day 14 or longer)
In the second phase there is a high viral load, people are still infectious but they are more likely to have symptoms in this phase – shortness of breath, fatigue, cough, and sometimes symptoms of a cold. The symptoms of loss of smell can set in during phase two as well. Blood clots start forming during this phase but generally don’t cause trouble till the third phase. ( Usually day 5-14)
In the third phase there is a massive inflammatory response. This is the time when people are at most risk of serious problems and death. They have strokes, they have pneumonia requiring ventilation, they have kidney failure… any system in the body can be impacted. This doesn’t happen to everyone. Interestingly the viral load isn’t necessarily high at this point. Some people continue to have lots of virus but others are simply fighting their own immune system. ( Starts somewhere between 2-3 weeks from infection… can last weeks to months)
The last phase is sometimes called the tail, or long COVID. It sounds a little like a very bad case of chronic fatigue syndrome. The symptoms vary and seem to include any of the symptoms from the prior phases from debilitating fatigue, hair loss, cough, diarrhea, low oxygen saturation, weakness, inability to smell, memory loss, difficulty thinking or concentrating. People report not being able to cross the house without low oxygen, shortness of breath or fatigue. They report oxygen dropping while they try to concentrate on responding to email. They are in short unable to participate in their normal life. Others are able to get back to their lives but don’t ever have enough energy or feel well.
Imaging studies of people in the long haul phase and those that have fully recovered can show persistent damage to the lungs, kidney, heart, brain tissue and other organs. The American Academy of Pediatrics is now recommending cardiac testing as part of return to sports examinations. We are still just at the beginning of understanding this last phase but it will inevitably change the future of health care by impacting large numbers of people.
