(NEXSTAR) – Three respiratory illnesses, COVID-19, respiratory syncytial virus (RSV) and the flu, continue to infect hundreds of thousands of Americans daily – which can make it hard to tell what’s wrong when you feel a cough kicking in.

All three viruses cause sickness with overlapping symptoms. A chart created by Children’s National Hospital in Washington, D.C. compares the most common differences at a glance.

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While cough and fever are common with all three, there are other ways the viruses differ. Sneezing is common with RSV, happens sometimes with COVID-19 and is rare with the flu, according to the hospital’s symptom chart. On the other hand, headaches and body aches are rare with RSV, happen sometimes with COVID-19 and are common with the flu.

Another thing to pay attention to is the “onset of symptoms,” Children’s National says. While COVID-19 and RSV both start gradual then escalate, the flu usually hits hard and fast.

With RSV, symptoms often go away in about a week, according to the Centers for Disease Control and Prevention. Symptoms persist longer with the flu, about one to two weeks, and can last even longer with COVID-19.

A chart created by Children’s National Hospital compares symptoms associated with COVID-19, flu and RSV. (Photo: Children’s National)

The severity of symptoms in all three cases varies from person to person.

Another key difference: There are vaccines for flu and COVID-19, but no vaccine for RSV – though researchers are working on one.

While examining your symptoms is a good place to start, doctors recommend getting tested to help inform next steps.

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“For both flu and for COVID, we have antivirals that work if taken early after signs of symptoms,” said Dr. Andrew Pekosz, a virologist and professor at Johns Hopkins Bloomberg School of Public Health. “So particularly if you’re in a high-risk group, it’s good to know that. … Those are important tools that we really have to keep using.”