Recently, Dr Joyeeta Basu, a physician, took to Twitter to write that she hasn’t seen a single case of Covid-19 in the last four weeks in Delhi NCR. “Getting patients tested for both RAT and RTPCR. Mostly seeing a lot of Influenza A and H1N1,” her post read. However, according to a bulletin by the Delhi Health Department on Wednesday, the national capital logged six new Covid cases in the last 24 hours, with the case positivity rate at 0.13 per cent. As such, considering a rise in such cases, how can one differentiate between the flu, H1N1, and Covid-19?
What are the three infections?
Notably, H1N1, also called swine flu, is a virus similar to the influenza viruses that cause illness in pigs. On the other hand, flu, or the common cold, is quite frequent during winter and seasonal changes and is, often, harmless. There are more than 200-300 viruses that may cause the common cold. “In each virus type, there can be subtypes and variants. The majority of the common colds are caused by rhinoviruses, respiratory syncytial viruses, influenza type A and type B viruses, etc,” Dr Anantha Padmanabha, Consultant, Internal Medicine, Fortis Hospital, Nagarbhavi told indianexpress.com in an earlier interaction.
Covid-19, on the other hand, is caused by the SARS-CoV-2 virus and is considered highly infectious. While many may experience mild to moderate respiratory illness and recover without requiring special treatment, others may become seriously ill and require medical attention. Older people and those with underlying medical conditions like cardiovascular disease, diabetes, chronic respiratory disease, or cancer are more likely to develop serious illness, according to the World Health Organization.
Causes and symptoms
Dr Manjeeta Nath Das, senior consultant, internal medicine, Narayana Super Speciality Hospital, Gurugram said it is necessary to check the symptoms of the patient, instead of assuming the illness to be seasonal flu, Covid, or N1H1. “Evaluate the symptoms of a person thoroughly. It will give a direction for treatment. If retro-orbital pain and severe backache are present, we can suspect dengue. If the patient is coughing, we should ask for Covid testing, and if the Covid report is negative, then we suggest H1N1 or swine flu testing,” Dr Das told indianexpress.com.
Dr Vigyan Mishra, Chief of Lab, Neuberg Diagnostics said that influenza (flu) and Covid-19 are both infectious respiratory illnesses, however, are caused by different viruses. “Covid-19 is caused by the coronavirus whereas flu is caused by the influenza virus. Covid-19 spreads quicker than the flu and can cause more severe illness in some people. When compared to the flu, those infected with Covid-19 may take longer to show symptoms and may be infectious for longer periods,” said Dr Mishra.
All three respiratory infections present very similarly with fever, cough, sore throat, tiredness, difficulty in breathing, stuffy nose, headache, and sometimes diarrhea, said Dr Sanjith Saseedharan, consultant and head critical care, SL Raheja Hospital, Mahim-A Fortis Associate.
Both Covid-19 and the flu can have different degrees of symptoms. But common symptoms that Covid-19 and flu share, according to Dr Mishra, include:
*Fever
*Cough
*Shortness of breath or difficulty breathing
(Fatigue (tiredness)
*Sore throat
*Runny or stuffy nose
*Muscle pain or body aches
*Headache
*Vomiting
*Diarrhea
*Change in or loss of taste or smell, although this is more frequent with Covid-19
Dr Mishra noted that if a person suffers from flu, they may observe symptoms anywhere from one to four days, while for Covid-19 a person may observe symptoms anywhere from two to five days, and up to 14 days after infection.
How do they spread?
Flu spreads from an infected patient to others only when they are symptomatic while Covid-19 can spread to others even when the infected patient is asymptomatic. Hence, Covid-19 can result in a larger spread as compared to the flu, resulting in epidemics and pandemics, mentioned Dr Saseedharan.
Severity
All the mentioned illnesses are contagious and tend to be severe in patients who are immunocompromised, elderly, or have comorbidities. However, in comparison to flu or H1N1, the severity of Covid-19 in patients is known to be much higher. “All three present very similarly with fever, cough, sore throat, tiredness, difficulty in breathing, stuffy nose, headache, and sometimes diarrhea. All the infections can cause severe problems like respiratory failure, pneumonia, sepsis, and multiorgan failure. However, secondary infections are lesser seen in Covid-19 as compared to the flu. Covid-19 is also known to cause clots in blood vessels, something that is not noticed in flu cases,” noted Dr Saseedharan.
Who is more likely to be affected?
Children and young adults are more likely to be infected with H1N1 or flu than Covid-19. Whereas the elderly population, which has developed some immunity to the flu and H1N1 virus due to previous infections, is less likely to get it, said Dr Saseedharan.
Both Covid-19 and swine flu are diagnosed with the help of a nasopharyngeal swab (Source: Express Photo by Praveen Khanna)Diagnosis
Dr Padmanabha said that experts generally do not investigate cases of the common cold as it rarely harms anyone. “If it is restricted to the upper respiratory tract, even an x-ray won’t show anything. Sometimes, doctors may take a nasal swab or a throat swab to diagnose. If the infection becomes more severe and we feel the patient needs more attention and specialised care, then we go for tests such as blood tests, x-rays, etc to differentiate,” the expert said.
Both Covid-19 and swine flu are diagnosed with the help of a nasopharyngeal swab, an oropharyngeal swab and a nasopharyngeal wash. Rapid tests are also available for both Covid-19 and the flu.
Treatment
Adequate rest and recovery is advised at home with simple home-cooked, fresh food, and proper hydration.
Post-recovery
Many people may experience post-Covid-19 illness which is called long Covid, something not seen with the flu, said Dr Saseedharan.
Prevention
According to the WHO, the most effective way to prevent infection with the virus that causes Covid-19 is to get vaccinated and follow prevention measures: “maintaining at least a 1-metre distance from others, wearing a well-fitted mask when keeping your distance is not possible, avoiding crowded and poorly ventilated places and settings, opening windows and doors to keep rooms well ventilated and cleaning your hands frequently.” It also advises that people should follow the advice “of your local authorities on getting the influenza and Covid-19 vaccines“.
📣 For more lifestyle news, follow us on Instagram | Twitter | Facebook and don’t miss out on the latest updates!
Common symptoms that Covid-19 and flu share include cough (Source: Getty Images/Thinkstock) 
Both Covid-19 and swine flu are diagnosed with the help of a nasopharyngeal swab (Source: Express Photo by Praveen Khanna)
Share
