When a relative of mine recently became seriously ill with what seemed to be a coronavirus infection, my first question was about timing. How many days ago did your symptoms start?
Marking your calendar at the first sign of illness, and tracking your fever and oxygen levels, are important steps in monitoring a coronavirus infection. Covid-19, the disease caused by the coronavirus, has been unpredictable in the range of symptoms it can cause. But when it turns serious, it often follows a consistent pattern.
While most patients recover in about a week, a significant minority of patients enter “a very nasty second wave” of illness, said Dr. Ilan Schwartz, assistant professor of infectious disease at the University of Alberta. “After the initial symptoms, things plateau and maybe even improve a little bit, and then there is a secondary worsening.”
While every patient is different, doctors say that days five through 10 of the illness are often the most worrisome time for respiratory complications of Covid-19, particularly for older patients and those with underlying conditions like high blood pressure, obesity or diabetes. Younger patients who develop complications may begin struggling a little later, as late as days 10 to 12. Most people who reach day 14 without any worrying symptoms (other than feeling miserable and fatigued) are likely to be on the road to recovery.
“With any other disease, most people, after a week of symptoms, they’re like ‘OK, things will get better,’” said Dr. Leora Horwitz, associate professor of population health and medicine at N.Y.U. Langone Health. “With Covid, I tell people that around a week is when I want you to really pay attention to how you’re feeling. Don’t get complacent and feel like it’s all over.”
It’s important to call a doctor if you have shortness of breath or any concerning symptom no matter what day of illness you are on. And don’t panic if you still feel lousy after a week of illness. It’s common for Covid symptoms to linger, and feeling unwell for more than a week doesn’t always mean you need medical treatment.
But tracking symptoms and paying special attention as the illness nears its second week has taken on new urgency as more doctors are seeing patients arriving at the hospital with an insidious form of pneumonia. On scans, patients with Covid pneumonia have a finding called “ground-glass opacities,” a hazy appearance in the lower part of both lungs. Oxygen levels may drop so slowly that the patient doesn’t even notice, a condition called silent hypoxia. Often it is not until oxygen saturation reaches dangerously low levels, causing severe shortness of breath, that they finally seek care.
The best way to monitor your health during this time is to use a pulse oximeter, a small device that clips on your finger and measures your blood oxygen levels. (There are phone-based apps meant to do this, but they have tested poorly) The normal oxygen saturation range is about 96 to 99 percent. If your blood oxygen reading drops to 92 percent, it’s time to call a doctor.
While at home, you can also increase the flow of oxygen to your lungs by not resting on your back. Resting on your stomach, in the prone position, can open parts of the lungs that are compressed when lying on your back. You can also change to resting on your left side or right side, or sit upright in a chair.
Dr. Anna Marie Chang, an associate professor of emergency medicine and director of clinical research at Thomas Jefferson University, was sick for about a week before her oxygen levels dropped to 88 on the ninth day of her illness. She went to the hospital and was treated with oxygen and rested mostly in the prone position for four days to recover.
It’s not clear why relatively young, healthy patients like Dr. Chang, who is 38, sometimes take a turn for the worse.
“The first part is viral illness and everything else,” said Dr. Chang. “Your body is developing your immune inflammatory response and trying to fight off infection. That system can get over stimulated, and that seems to be what causes the acute worsening. We’re seeing that around days seven to 10.”
Dr. Chang cautioned that patients should listen to their bodies and not be too strict about following a timeline of symptoms. “The human body does not follow the perfect manual,” she said.
The problem, say doctors, is that the public health guidance so far has been to tell patients to ride out the illness at home and seek medical care or return only if they experience severe shortness of breath. As a result, too many patients are waiting too long to contact a doctor.
“From a public health perspective, we’ve been wrong to tell people to come back only if they have severe shortness of breath,” said Dr. Richard Levitan, a well-known emergency room doctor from New Hampshire who has called for widespread use of home pulse oximeters during the first two weeks of Covid-19 illness. “Toughing it out is not a great strategy.”
Dr. Levitan notes that while many patients may take a turn for the worse five to 10 days into the illness, he hesitates to be too specific about the timeline because not every patient is clear about exactly what day their illness began.
“Patients will sometimes define a time course of illness differently than what you would expect,” Dr. Levitan said. “When you ask someone how long have you been sick, I find a patient says a few days and his wife will say, no, he’s been sick for a week.”
But what if you don’t have a home pulse oximeter to monitor your health? The devices are now in short supply or can take weeks to be delivered.
Some medical practices are sending their patients home kits that include pulse oximeters, so check with your doctor about how you might be monitored. Ask friends now if they have a pulse oximeter so you have a plan in place to borrow one for two weeks should you get sick (the device is easily sanitized).
If you are still feeling lousy a week into your illness and don’t have a pulse oximeter, you can also check in with an urgent care clinic and ask them to check your oxygen level. If you are concerned, talk to your doctor about whether a visit to an urgent care center or the emergency room is warranted.
In the absence of a pulse oximeter, one rough measure of respiratory function is a self-test called the Roth score. It requires the patient to take a breath and try counting to 30. If a patient can’t make it to the number 10 (or seven seconds) without another breath, it’s likely their oxygen level has dropped below 95. If they can’t count to the number 7 (or five seconds), their oxygen score may be below 90 percent. The test is not perfect, nor has it been studied in Covid-19. A University of Oxford team said the Roth score should not be used because it hasn’t been validated and could give false reassurance.
Another physical but subtle sign of falling oxygen: Patients may start taking short, fast breaths to compensate, although they may not notice they are doing it. Patients with low oxygen levels might also have a blue tinge to their lips or skin. That’s why a video conference with your doctor can be helpful if you’re not sure about whether you need to go to the hospital.
Here’s a look at the timeline of Covid symptoms. While this can serve as a general guide, symptoms can appear at any time. Always listen to your body and consult with a doctor for guidance about your specific case.
Days 1 to 3
Early symptoms of Covid-19 vary widely. It can start with a tickle in your throat, a cough, fever, headache and feeling winded or just a little pressure in your chest. Sometimes it begins with a bout of diarrhea. Some people just feel tired and lose their sense of taste and smell. Many people have several symptoms but no fever. Some patients with gastrointestinal symptoms go on to develop respiratory symptoms, while others don’t.
Days 4 to 6
Some patients never develop more than mild symptoms, or none at all. Others begin to feel terrible, with an ever-present fever, aches, chills, cough and an inability to get comfortable.
Some children and younger adults with mild disease may develop rashes, including itchy red patches, swelling or blistering on the toes or fingers, similar to frostbite. The exact timing isn’t clear, and the symptom may appear early in the infection or after it has passed. That’s what happened to Dr. Schwartz, who developed respiratory symptoms and then blisters on his feet. “It seems that a lot of these individuals, including myself, test negative” on coronavirus swab tests, he said. “I presume it’s a false negative. It could be that what we’re seeing is an immunological phenomenon that occurs after the initial infection is on the mend.”
Days 7 to 8
For some lucky patients with mild illness, the worst is over after a week. Guidelines from the Centers for Disease Control and Prevention say patients whose symptoms have improved and who haven’t had a fever for three days can leave isolation.
But some patients who have felt terrible continue to feel terrible or get worse. And some patients might start to feel better briefly then take a turn for the worse.
Patients should monitor their oxygen levels and check in with a doctor if they start to feel unwell. “We should instruct patients to have a lower threshold for contacting their doctor,” Dr. Levitan said. “I believe they should contact their physicians to have monitoring if they’re feeling worse.”
Days 8 to 12
Monitoring should continue for the second week of illness. Patients may feel better sleeping on their stomachs or sides.
“Days eight to 12 are when we have a really good idea if someone is going to get better or get worse,” said Dr. Charles A. Powell, director of the Mount Sinai-National Jewish Health Respiratory Institute. “The major thing we worry about is a worsening at eight to 12 days — an increasing shortness of breath, worsening cough.”
Dr. Powell said a home oxygen monitor can signal if someone needs to come in. Otherwise, patients should talk to their doctors.
“If it’s difficult for the person at home to feel comfortable, and it’s difficult for the family to feel things are manageable, that would lead a physician to suggest the patient come in for evaluation,” said Dr. Powell. “We don’t want to wait too long for blood oxygen levels to get worse.”
Days 13 to 14
Patients who had mild illness should be well recovered. Patients who had worse symptoms but maintained normal oxygen levels should feel mostly recovered after two weeks. However, patients with severe symptoms and those who needed additional treatment because of low oxygen may still feel unwell and fatigued and take longer to recover.