Flu season had just combined with the current COVID-19 pandemic, and this "twindemic" worries public health experts that people might just shake off alarming symptoms.

Flu Vaccine
(Photo by Joe Raedle/Getty Images) Flu Vaccine

While it is true that COVID-19 and the flu have some symptoms in common, they also have their differences.

One example is that both COVID-19 and the flu are caused by different viruses despite both being contagious respiratory illnesses.

Here are some key differences in flu and COVID-19 symptoms, as said by the Centers for Disease Control and Prevention:

Incubation Period

Medical News Today said in an article that people who suffer from COVID-19 develop symptoms between one to 14 days.

A 2020 study said the incubation period for COVID-19 is 5.1 days on average. On the other hand, the flu shows symptoms within one to four days.

The CDC also noted that COVID-19 symptoms are the same across all ages, but added that children usually show fever and cold-like symptoms like a cough or runny nose.

Spreading the Virus

Most people with the flu can pass on the virus for about one day before they actually show symptoms.

Usually, older children and adults with the flu will be most contagious during the first three to four days of their illness. Many could still infect other for about seven days. Those who have weaker immune systems can also pass the virus along for much longer.

As for COVID-19, for how long some can spread the virus is still being studied. But CDC added that it is possible to pass on COVID-19 for about two days after noting signs or symptoms.

People will also remain contagious for at least 10 days after the symptoms appeared. Asymptomatic patients can also possibly pass the illness for at least 10 days after testing positive of the virus.

Loss of Sense of Smell

One of the key differences between COVID-19 and the flu is the weakened sense of smell and sense of taste.

A European study said that of 417 people with mild to moderate COVID-19, more than 85 percent of the patients noticed that they were experiencing loss of smell.

This symptom is known as anosmia. It was found by Chemical Senses that 34 to 95 percent of COVID-19 patients experience this.

A Mayo Clinic study also reported that COVID-19 patients are 27 times more likely to get anosmia, making it a better indicator of the illness over fever.

Some reports also suggest that the effects of anosmia during COVID-19 could be long-term, noted the National Geographic.

Shortness of Breath

Another study from the National Library of Medicine noted that half of the patients with severe cases of COVID-19 develop shortness of breath. It is better known as dyspnea and takes about a week after the symptoms start to arise.

Having this symptom could mean severe respiratory problems. With this, patients may need oxygen therapy and even a ventilator.

These two symptoms can help people distinguish the difference between the flu and COVID-19. But they both don't make a sure diagnosis. It is still important to seek medical attention immediately.

A list of symptoms for both the flu and COVID-19 can be seen on the CDC website.

Check these out!

Preparing for Flu Season: Can You Get COVID-19 and the Flu at the Same Time?
Influenza Symptoms, Treatment & Vaccine: Death Cases Hit 200 in California; Is Vaccination Still Effective?
Ease Common Colds and Flu With These Affordable Humidifiers