published : 2023-11-08

Cold, flu, COVID-19 and RSV: How to identify the differing symptoms and stay safe

There's 'very much overlap' between the four conditions, according to Dr. Marc Siegel

A photo of a person blowing their nose with a tissue, taken with a Nikon D850 camera.

For those who get sick during the fall and winter, the diagnosis could be a toss-up.

With the threat of the common cold, flu, COVID-19 and RSV in the mix, it can be tricky to determine the culprit.

Caused by viruses, a cold is marked by typical symptoms such as a runny or stuffy nose, sore throat, cough, sneezing, nasal congestion, headache, slight body aches and a low-grade fever, according to Mayo Clinic.

Adults may catch a cold two or three times a year, while infants and young children can get them more often.

Most people recover from a cold in about a week, and medical care is generally unnecessary unless symptoms worsen.

The common cold is harmless, although it 'might not feel that way,' according to Mayo Clinic.

Colds are most frequently caused by rhinoviruses, according to the Centers for Disease Control and Prevention (CDC).

They are spread through respiratory droplets released by coughing and sneezing, or through personal contact such as shaking hands or hugging.

Influenza symptoms may be similar to those of the common cold, but the repercussions could be more severe.

The flu is caused by influenza viruses that impact the nose, throat and sometimes the lungs, according to the CDC, and can cause mild to severe illness.

In some cases, the flu can be deadly.

The virus has resulted in anywhere from 12,000 to 52,000 deaths annually in the years 2010 to 2020, per CDC data.

A close-up photo of a person's hand holding a thermometer to their forehead, taken with a Canon EOS 5D Mark IV camera.

Flu symptoms are usually sudden, Siegel said — and can include fever, chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, and sometimes vomiting and diarrhea.

The sudden onset of feeling unwell often differentiates the flu from the common cold.

The CDC noted that it's 'impossible' for people to tell if they have the flu based on symptoms alone, which is why diagnosis requires testing by a medical professional, most commonly with rapid influenza diagnostic tests (RIDTs).

The flu is spread by the same respiratory droplets as a cold, and can also be transmitted by touching infected surfaces and then touching your face.

COVID-19 has all the same symptoms as cold and flu, including fever, chills, cough, body aches, sore throat, congestion, runny nose, fatigue, and headache.

Siegel noted that some additional symptoms of COVID-19 are characterized by sore throat, loss of taste, brain fog and shortness of breath.

One of the reasons for running rapid COVID tests on patients with these symptoms is to distinguish the virus from the others, Siegel said.

COVID-19 can also be detected through more accurate PCR testing, which will deliver a result within three days.

People should seek emergency medical attention if symptoms develop into breathing trouble, persistent chest pain or pressure, new confusion or an inability to stay awake, as well as pale, gray or blue-colored skin, lips or nail beds, according to the CDC.

Coronavirus prevention measures include staying up to date with vaccines, improving ventilation in indoor spaces, testing for COVID, staying home when symptoms arise, and avoiding contact with people who may be infected, the agency stated.

Other preventative measures include wearing masks or respirators, avoiding crowded areas and keeping distance from others.

RSV, or respiratory syncytial virus, can cause the same basic symptoms of runny nose, cough, sneezing, and fever.

A photo of a person getting a flu shot at a vaccination clinic, taken with a Sony Alpha a7 III camera.

Other symptoms of the virus, such as wheezing and a decrease in appetite, could differentiate it from other conditions, according to the CDC.

While infants are at the highest risk for RSV infection, they may have different symptoms, such as irritability, decreased activity and breathing difficulties.

Infants and older adults are most at risk for RSV, according to the CDC.

As Siegel noted, RSV patients can become short of breath and may spike a 'very high' fever, which could require an ER visit.

Infants and older adults are at risk of more severe infection, which can develop into other conditions like bronchiolitis and pneumonia, the CDC states.

Hospitalization may also be necessary for infants and older adults who experience dehydration or trouble breathing.

Most RSV infections will improve within one week, according to the CDC, and can be treated with over-the-counter medications and at-home care.

While there are subtle differences between RSV and other conditions, protocols for transmission and prevention remain mostly the same, including distancing from people with symptoms and being careful when touching foreign surfaces.

Multiple RSV vaccines are available for all ages and are recommended by the CDC as prevention aids.

Angelica Stabile is a lifestyle writer for Fox News Digital.