Is it Covid, Flu or RSV? The table compares the differences in symptoms

Together, Covid, influenza and respiratory syncytial virus (RSV) are driving a nationwide wave of respiratory illness.

According to the Department of Health and Human Services, approximately 76% of US hospital beds are full. Pediatric beds are at a similar level, though six states have 90% or more pediatric beds full, according to an analysis of HHS data by NBC News.

Covid, flu and RSV can be difficult to tell apart because they share many symptoms. But it’s helpful to know which virus you have because it determines the treatment you should get and how long you should isolate.

Some distinguishing features—either symptoms or how the disease progresses—can help distinguish between viruses. Here are five factors to consider.

Some symptoms are specific to specific viruses

A runny nose, cough, congestion or sore throat can occur as a result of any of the three viruses or the common cold. But loss of taste and smell is more often associated with Covid than with the flu or RSV. And wheezing is often a symptom of a serious RSV infection, which usually occurs in children or older adults.

The only way to know for sure is to get tested.

“I don’t think anyone would say, ‘Hey, listen, I think you have a virus based on your symptoms,’ and say with certainty what the virus is,” said Dr. Frank Esper, a pediatric infectious disease specialist. at the Cleveland Clinic.

Do the symptoms appear gradually or all at once?

Flu symptoms tend to develop more suddenly than Covid or RSV symptoms.

“Flu classically comes first with a sudden fever that comes on quite quickly. This contrasts somewhat with RSV and Covid, where we consider a slow escalation of symptoms,” said Dr. Scott Roberts, an infectious disease specialist at Yale Medicine.

How long has it been since exposure?

Diseases have different incubation periods — the time between exposure and symptoms. On average, flu symptoms develop two days after exposure to the virus, while RSV symptoms usually take about four to six days to appear, and the typical incubation period for Covid is three to four days for the omicron variant.

“If I go to a party and have symptoms the next day, it’s probably the flu because the incubation period can only be 24 hours,” Roberts said.

Age makes a big difference in the symptoms and severity of the disease

RSV is unlikely to make a healthy adult feel very ill, while Covid and flu certainly do.

“In general, if you’re a young healthy adult or you’re not at the extremes of age and you get a pretty severe illness, it’s probably not RSV,” Roberts said.

The groups most vulnerable to severe RSV infections are infants, children with lung disease, adults age 65 and older, and people with weakened immune systems.

Symptoms may also look different depending on your age and immune status. Many children encounter respiratory viruses for the first time this year as they return to regular schooling and socializing, so their bodies may have a harder time clearing the infection, which can lead to more far-reaching symptoms.

According to Esper, nearly a quarter of children have gastrointestinal symptoms (such as diarrhea, stomach pain, or vomiting) from viral infections. This is less common in adults with seasonal flu or RSV.

People with weakened immune systems, meanwhile, are more likely to develop severe symptoms or pneumonia from any of the three viruses.

Consider which virus is circulating the most in your community

Disease experts predict Covid cases will rise during the holiday season as more people travel and huddle indoors. Average daily cases reported to the Centers for Disease Control and Prevention have already increased by nearly 11% over the past two weeks, according to NBC News.

However, local levels of Covid transmission are difficult to determine because many people use home tests. RSV and flu tests, on the other hand, are performed in a doctor’s office or ordered by prescription.

Nationally, RSV infections appear to have passed their peak. Although the CDC does not keep a national count of RSV cases, the number of positive weekly tests dropped from more than 17,000 in the week ending Nov. 5 to about 9,000 in the week ending Saturday.

In contrast, flu cases are skyrocketing. The national rate of positive flu tests rose from about 8% in the week ending Oct. 30 to nearly 15% in the week ending Nov. 13. The number of flu hospitalizations is the highest this time of year in more than a decade.

Esper said he expects the Cleveland Clinic to be “swimming in flu” in two weeks.

However, the picture varies by region. In the Northeast, Roberts said, “We’ve seen an increase in RSV over the last one to two months and it’s actually leveling off — which is great news — and then the flu, just in the last few weeks we’re seeing an exponential increase.”

“The US Southeast—Georgia, Alabama, Mississippi—saw kind of the opposite. Initially they saw an increase in influenza and then now you see RSV starting to catch up,” he added.

Available treatments and vaccines

Unlike Covid and the flu, there are no vaccines or universally prescribed treatments for RSV.

“RSV probably scares me the most because there’s nothing you can do about it and so many young kids haven’t seen it. We’re really seeing record increases in our children’s hospitals,” Roberts said.

To shorten the duration of flu symptoms, doctors usually prescribe Tamiflu or one of three other approved treatments. For some people with Covid, doctors may prescribe Paxlovid.

Dr. Ashish Jha, the White House’s co-ordinator of the Covid-19 response, highlighted the benefits of flu shots and Covid boosters.

“At this point where we have a lot of flu, we still have a fair amount of RSV, we still have a good amount of Covid, the most important thing for people to do is to get vaccinated,” Jha said at Tuesday’s briefing. “It keeps you out of the hospital.

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