Is it Covid-19 or flu? Top doctor explains how to spot the difference

As the rainy season brings a rise in respiratory illnesses, many people are left wondering whether their fever, cough or body aches are caused by Covid-19 or seasonal influenza. While the two viral infections share several symptoms, recognising the differences and seeking timely medical advice can help prevent complications, particularly among vulnerable groups.

According to Dr Raghunandan S K, Attending Consultant, Internal Medicine, KIMS Hospitals, Mahadevapura, Bengaluru, both infections become more common during this time of the year, making awareness and early diagnosis especially important.

Why respiratory infections rise during the rainy season

"The rainy season marks an increase in viral conditions such as flu and Covid-19 infections. This is because both conditions are among the common respiratory diseases that exhibit overlapping symptoms. As such, it is quite challenging for someone to tell the difference between the two infections," says Dr Raghunandan.

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"Nevertheless, it is important to diagnose and manage these infections, especially in people who are prone to getting complications."

The symptoms they have in common

According to Dr Raghunandan, both influenza and Covid-19 can present with many of the same symptoms.

"Both flu and Covid-19 present similar symptoms, which include fever, cough, sore throat, body pains, fatigue, headache and chills. The symptoms in most instances are mild and can resolve themselves."

However, he points out that Covid-19 may still present with certain symptoms that are less commonly seen with seasonal flu.

"While the symptoms for COVID-19 are broad, some people get a loss of smell and taste, although this symptom is less prevalent in the new strains. Additionally, some patients may also experience digestive problems like nausea, vomiting or diarrhoea, which is not very common with seasonal flu."

One key difference lies in how symptoms begin

Although the symptoms often overlap, the way they develop can sometimes offer useful clues.

"Yet another major difference is the onset of symptoms. The influenza virus often shows an acute onset of symptoms, whereby one experiences a high fever, muscle pains and fatigue suddenly."

"As for the Covid-19 virus, in most cases, the symptoms can be experienced gradually, although it is dependent on the variant."

Dr Raghunandan also notes that Covid-19 may have longer-lasting effects for some individuals.

"Moreover, Covid-19 is associated with higher chances of prolonged fatigue, cough and other symptoms even weeks after the initial infection."

Testing is the only way to know for sure

Despite the differences, symptoms alone cannot reliably distinguish between Covid-19 and influenza.

"It should be noted that it is impossible to distinguish between Covid-19 and influenza based on the symptoms alone."

"It is always advisable to conduct tests like the RT-PCR test and rapid antigen test for Covid-19 to confirm the diagnosis. At times, when one is at high risk or needs to be admitted to hospital, it is recommended to conduct an influenza test."

Warning signs that should never be ignored

Whether the illness is caused by Covid-19 or influenza, some symptoms require urgent medical attention.

"Some of the red flags that require immediate medical intervention include difficulty breathing, persistent chest pain, confusion, bluish lips or face, high fever unresponsive to medication, dehydration or worsening symptoms after initial improvement."

He adds that some people should seek medical advice as early as possible.

"Elderly people, pregnant women, infants and individuals who suffer from chronic illnesses like diabetes, heart disease, lung disease, kidney disease, or who are immunocompromised should get expert advice early when experiencing any respiratory symptoms."

Simple precautions can reduce the risk

Good respiratory hygiene continues to play an important role in preventing the spread of viral infections.

"In the rainy season, the practice of proper respiratory hygiene becomes imperative. Washing hands regularly, covering the nose and mouth during sneezing or coughing, wearing masks when experiencing symptoms or going to public places, and avoiding contact with vulnerable individuals while sick are highly recommended."

"Drinking plenty of water, getting enough sleep and following a healthy diet may also speed up the process of recovery."

Vaccination remains one of the best forms of protection

Dr Raghunandan stresses that vaccination continues to be one of the most effective ways to reduce the risk of severe illness.

"More importantly, however, vaccination is still one of the most effective preventive measures. Yearly flu vaccination and Covid-19 vaccination, according to recommendations, can help prevent severe cases, hospitalisation and complications."

Instead of self-medicating, particularly with antibiotics, he advises people to seek proper medical care.

"Instead of taking antibiotics by yourself, you should visit a doctor and undergo proper diagnosis and treatment."

As respiratory viruses continue to circulate during the rainy season, recognising symptoms early, getting tested when necessary and following basic preventive measures can go a long way in protecting both individual and community health.