The symptoms of COVID-19 and the flu can differ in intensity, ranging from asymptomatic (having no symptoms) to severe symptoms. Taste and smell change or disappear, though COVID-19 patients experience this more frequently. Symptoms of COVID-19 and the flu include:
Sore throat; fever or feeling like you have the chills; Cough
Breathing difficulties or shortness of breath, Fatigue (tiredness)
Runny or stuffy nose
Muscle pain or body aches
Headache
Vomiting
According to Dr Akshay Anant Dhamne, Medicine, Physician Consultant at DPU Private Super Specialty Hospital, Pimpri, Pune, in the flu, typically a person may experience symptoms anywhere from one to four days after infection. Whereas in COVID-19 a person may experience symptoms anywhere from two to five days, and up to 14 days after infection. Though highly immune-evasive, the new JN.1 variant has so far caused mostly mild cases. Symptoms are fever, cough, runny nose, sore throat, body ache and fatigue.
If a person has COVID-19, they could be contagious for a longer time than if they have flu.
Flu:
People with flu virus infection are potentially contagious for about one day before they show symptoms. However, it is believed that flu is spread mainly by people who are symptomatic with flu virus infection.
Older children and adults with flu appear to be most contagious during the first 3-4 days of their illness, but some people might remain contagious for slightly longer periods.
Infants and people with weakened immune systems can be contagious for even longer.
COVID-19:
On average, people can begin spreading the virus that causes COVID-19 2-3 days before their symptoms begin, but infectiousness peaks one day before their symptoms begin.
People can also spread the virus that causes COVID-19 without experiencing any symptoms.
On average, people are considered contagious for about eight days after their symptoms begin. Overall, COVID-19 seems to cause more severe illness in some people. Severe COVID-19 illness resulting in hospitalisation and death can occur even in healthy people. Some people that had COVID-19 can go on to develop post-COVID conditions or multisystem inflammatory syndrome (MIS)
Most people who get flu will recover on their own in a few days to two weeks, but some people will experience severe complications, requiring hospitalisation. Some of these complications are listed above. Secondary bacterial infections are more common with influenza than with COVID-19. Diarrhea is more common in young children with flu than in adults with flu.