By now, we all should have memorized the key symptoms of the new coronavirus that public health officials have hammered home: fever, cough and trouble breathing.
However, that message may have given some who thought they had to have all three symptoms at once a false sense of security.
The earliest reports on the disease caused by the new germ, now dubbed COVID-19, were based on patients sick enough to see a doctor or go to a hospital. Many, though not all, of them had the three symptoms.
As we practice social distancing and worry about who'll be next to fall, though, an important question is, How does this disease start? Knowing the early symptoms would help people know when to isolate themselves even more and talk to their doctors about testing.
While thousands of people have contracted COVID-19 over the last few months, information about its earliest stages has been slow to trickle out. Doctors said there are still important gaps in what they know. And, unfortunately, many of the early symptoms of COVID-19 overlap with other common health problems.
"There is no clearly defined syndrome at this point," said Nuala Meyer, a pulmonary and critical-care medicine doctor at Penn Medicine.
Symptoms can be subtle: It is known that some people infected with the virus have no symptoms or symptoms that are so mild they're not noticed.
Daniel Mueller, an infectious disease doctor at Temple University Hospital, said that infected people might feel "just slightly under the weather for a few days. ... They might just feel a little tired or a little achy." It's the sort of feeling you'd have if you thought you were coming down with something, but nothing very worrisome.
Then they might start having a dry cough. Later on, in some people, shortness of breath comes on. "They don't always happen together," Mueller said.
It's not like flu: Unlike flu, which announces itself suddenly with fever and muscle aches, the early stages of COVID-19 can go on a few days.
Reynold A. Panettieri Jr., vice chancellor for clinical and translational science at Rutgers University, said some mild cases last just 72 to 96 hours. Others who are not sick enough for hospitalization may have symptoms for two weeks. Presentation of the disease is "very individualistic and very heterogeneous." Some are barely affected and some have "shaking chills" and muscle aches, he said. Shortness of breath may manifest in two to three days. More severe symptoms may portend a rougher course, but that's not yet clear.
"You just don't know whether they're going to progress," he said. In severe cases, patients develop pneumonia and need help breathing. "The susceptibility to progression is unclear."
Fever? Yes and no. Meyer would add sore throat to the list of early symptoms. She said most patients will eventually have a fever, but it "may not be in the first five days."
A report about the Chinese outbreak published in the New England Journal of Medicine said that 43.8% of COVID-19 patients had a fever when admitted to a hospital and 88% developed one during their stay. The researchers warned that cases could be missed if doctors considered fever part of the case definition.
A rarely mentioned early symptom is gastrointestinal distress. About 10% of cases can start with a couple days of diarrhea, abdominal pain, nausea or vomiting and then develop respiratory symptoms, said David A. Johnson, who is chief of gastroenterology at Eastern Virginia Medical School and has reviewed studies on the new disease. He said this makes some sense because the new virus first targets a type of cell that lives both in the lungs and in parts of the digestive tract.
There is evidence of viral shedding in feces, he said. That alone is not proof that virus in stool is infectious, he said, but is reason to worry that the disease can be transmitted through the fecal-oral route. It's another argument for good hand hygiene and bathroom cleaning. In a Chinese study, the shedding continued for up to 12 days after people tested negative for the virus, he said.
Gavin Macgregor-Skinner, who is an assistant professor in the Department of Public Health at Penn State College of Medicine, also trains people in hospitals and other organizations in infection prevention and control. He is frustrated by the lack of information this many weeks into a pandemic. He said medical journals can be too slow to provide information, and doctors should find quicker ways, such as a clearinghouse, to share data.
For now, he asks the 37 members of his prevention team to take their temperatures in the morning and evening. That way they'll know their personal baseline. If the temperature goes up, he wants them to stop working and test every three hours.
He doesn't know whether fever is the first symptom, but low-grade fever is "definitely present" in the disease. He also wants people to stay away from others if they have any respiratory symptoms. He agreed that breathing difficulty is not an early sign of the disease.
He didn't know about gastrointestinal symptoms, but he had strong words about infection control when fecal-oral transmission is a possibility. Active virus in feces can spray into the room when you flush. So, close the lid when flushing. You shouldn't have any personal items near the toilet he said. "Don't have your tooth brush next to your toilet, ever," he said.
Mueller said those major symptoms _ fever, cough and shortness of breath _ warrant a call to the doctor and a discussion about whether to be tested. He would set the threshold lower for transplant patients or those with chronic heart and lung disease. Shortness of breath could be a sign of pneumonia and should get immediate attention, he said.
