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November 17, 2022 – The overlapping symptoms of respiratory viruses with household names – COVID-19, flu, common cold and RSV (respiratory syncytial virus) – can make it difficult to tell them apart.
But how quickly symptoms appear, how long they last, and even what symptoms you have can be important clues. A few treatments are available, and they are most effective when taken early. So it’s worth finding out which infection hits you, a friend or loved one.
The American Academy of Pediatrics came up with one helpful chart which symptoms are most likely to occur with which respiratory diseases. “I think that’s a really good chart. And I think it’s mostly the same for kids and adults,” says Patricia (Patsy) A. Stinchfield, a registered nurse and president of the National Foundation for Infectious Diseases (NFID).
One exception she offered is that children with COVID-19 report less loss of taste and smell compared to adults.
“It’s extremely, extremely difficult to differentiate our symptoms between influenza, RSV, and COVID-19 … for parents and physicians on this matter,” says Mobeen Rathore, MD, a member of the American Academy of Pediatrics’ Infectious Diseases Committee.
Stinchfield agrees that these viruses cause many of the same symptoms, like congestion, a cough, and possibly a fever. But that doesn’t mean it’s impossible to tell them apart.
The Fast and the Furious
“After 44 years as an infectious disease nurse, one of the things I would ask people who want to find out how sick they are is when they started.” In both children and adults, the flu often comes on very quickly. “It’s like a minute that a kid is playing or an adult is working – and the next minute… it’s that feeling like you’ve been hit by a Mack truck.”
In contrast, the other viral diseases tend to progress more slowly, she says. “People will say they feel like they’re getting something, have chills, have a sore throat, or feel ‘blah.'”
GI symptoms can be another clue. Vomiting and diarrhea are more common in COVID-19, and to some extent influenza, than in RSV. This happens in part because the COVID-19 virus binds to ACE2 receptors located in both the lungs and gut, so it can affect both parts of the body.
Additionally, it is widely accepted that loss of taste and smell is a unique sign of COVID-19 infection. This can help you distinguish COVID-19 from other viral diseases.
Symptoms indicative of RSV
More sneezing, “copious amounts” of nasal mucus – snot – coming from a runny nose, and wheezing are some typical symptoms of RSV. Wheezing is when a child or adult makes a whistling sound when breathing. Stinchfield says, “Wheezing sounds are not as common with COVID or influenza as they are with RSV.”
“RSV is more of an upper respiratory tract infection, and people tend to have more of what we call bronchiolitis,” says Rathore. Bronchiolitis is inflammation and congestion in the small airways of the lungs, which in turn can cause the wheezing sound.
Additionally, some people with RSV have such trouble breathing normally that they recruit other muscles for support, including muscles just above and below the breastbone.
The cold is still there
“People are talking a lot about RSV right now – And rightly so – but at least what we see is very different,” says Rathore. The latest internal figures from the American Academy of Pediatrics’ Infectious Diseases Committee suggest that the common cold is currently the predominant virus, followed by influenza, RSV and COVID-19.
Rathore estimates that about 35% of patients who come in with a viral illness test positive for the rhino-enterovirus that causes the common cold.
“So it’s probably a lot more common than any of the other infections that we’re talking about,” he says. And yes, the common cold is more common, “but it’s also relatively less common for it to cause more serious illnesses.”
Testing remains essential
Stinchfield shared two main messages. Testing is the only reliable way to diagnose a viral disease. “So if someone says, ‘That’s definitely RSV,’ and your child hasn’t been tested, you really don’t know.”
Testing very young children is important because they can’t describe their pain, says Rathore, who is also chief of the Division of Pediatric Infectious Diseases and Immunology at the University of Florida at Jacksonville.
Tests can also confirm flu or COVID. “The nice thing is that there are some combo rapid tests that we use in clinics that can look at COVID-19, the flu and RSV all in one,” says Stinchfield. She hopes that similar combined home tests will become available in the future.
Another reason to get tested is, “There’s a treatment for COVID-19 and a treatment for influenza, so it’s important to know what you have so you can potentially benefit from early treatment.”
Stinchfield also says effective vaccines exist for COVID-19 and influenza, and a vaccine to protect against RSV is in development.
Don’t hesitate to get help
Trust your instincts when you feel like a viral illness is getting worse, says Stinchfield. “Just listen to your gut feeling. If you’re afraid of saying, “That’s not right,” “My husband doesn’t look good,” “My baby doesn’t look good,” seek medical help.
“That’s what we’re here for,” she says.
Stinchfield acknowledges there may be longer than usual wait times to see a pediatrician or infectious disease doctor due to the RSV outbreak. Also, consider a virtual appointment if you’re concerned about exposure to other people in a medical setting, she says.
Is a worrying winter ahead of us?
With several notable viruses circulating, some experts are warning of a “twindemic” or “tripledemic” coming winter. Rathore went one step further. “Actually, I’m talking about the possibility of a quaternary pandemic.” In addition to COVID-19, RSV and the flu, the common cold virus is also widespread.
In fact, in his northeast Florida area, RSV rates appear to be falling, flu rising, and with COVID-19 “there are concerns it could come back like it has in previous seasons.” At the same time, cold rates remain stable.
“There is nothing that can be said with certainty about which viruses will dominate in the coming winter,” says Rathore. But the flu season in the southern hemisphere has been relatively severe, and that often predicts what’s happening in the United States and other parts of the northern hemisphere, he says.
On a positive note, last season’s flu vaccine did well to protect against the flu strain common in Australia and elsewhere, which might be reassuring here. “So that’s one more reason that everyone who’s eligible for the influenza vaccine should get it.”