In pre-pandemic times, coming down with a cough, body aches, and overwhelming fatigue was a pretty clear sign of a nasty cold or flu. But because of COVID-19, you’re probably more worried about the coronavirus if those symptoms start to show up—especially because COVID-19 has a higher death rate than the typical flu.

Everything we know about the respiratory disease has certainly evolved throughout 2020, especially its symptoms. When the pandemic first hit, doctors put people on high alert for three major red flags: a fever, dry cough, or shortness of breath.

The Centers for Disease Control and Prevention (CDC) now has a list of 11 official COVID-19 symptoms, which still doesn’t encompass every possible sign of illness. But certain symptoms seem to be more common than others—including a high fever, which is your cue to get a doctor on the phone.

But what if you feel sick in other ways, and you don’t have a fever? Here’s everything doctors want you to keep in mind.

Back up: Why does COVID-19 cause a fever, anyway?

At a very basic level, having a fever means your body temperature is higher than normal. A fever is different from an elevated temperature, though. The CDC and the medical community at large only consider a temperature of at least 38C a true fever.

“A fever is the body’s natural response to an infection, including COVID-19,” says infectious disease expert Dr Amesh A. Adalja, senior scholar at the Johns Hopkins Center for Health Security.

Here’s how it works: Your body temperature spikes because your immune system is trying to kill an unwelcome pathogen, often a virus or bacteria. At your normal temp, these illness-causing invaders can easily replicate—but when things heat up, it becomes harder for them to survive.

Can you have COVID-19 without a fever?

It’s definitely possible. “Fever is one of the most common symptoms with COVID-19, but many people never have one,” says Dr Richard Watkins, an infectious disease physician and a professor of internal medicine at the Northeast Ohio Medical University.

Dr Adalja agrees. “Fever is part of a constellation of symptoms and it may or may not be present in any individual,” he says. “You can be symptomatic and not have a fever.”

A fever can also go up and down when you have COVID-19 (which is true with any illness), and it’s possible for someone with the virus to technically have a fever at some point and not even realise it, Dr Adalja says.

On the flipside, some people with COVID-19 have no symptoms at all, while others have unusual signs of the virus, including just GI symptoms like diarrhea and vomiting. “Everyone’s immune system is different,” Dr Adalja says. In short, the virus can present itself in a slew of ways, but these are the most common signs to know:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

Rarer symptoms, like skin rashes and conjunctivitis have also been linked to COVID-19.

What should you do if you have COVID-19 symptoms without a fever?

“Many people with COVID-19 do get a fever, but it’s not something that’s ironclad,” Dr Adalja emphasises. “It shouldn’t be used as the sole arbiter on whether you have COVID-19 or not.”

If you have unusual symptoms but no fever, he still recommends getting tested. It’s possible that you could have a cold or the flu, but with rising cases, it’s best to be safe.

Many people diagnosed with COVID-19 will have a mild illness and eventually start to feel better at home with plenty of rest, fluids, and over-the-counter pain relievers or cough medications. If you have any of the following symptoms (or any severe symptoms that concern you), head to the hospital immediately:

  • Trouble breathing
  • Persistent pain or pressure in the chest
  • New confusion
  • Inability to wake or stay awake
  • Bluish lips or face