New Delhi, March 17
India is currently seeing a surge in respiratory illness commonly characterised by cough, body ache, fever, and sore throat. But how to know whether it is influenza, caused by H3N2 virus, or Covid, caused by Omicron sub-variants XBB.1.16 and XBB.1.5?

According to data from the Indian Council of Medical Research (ICMR), there has been a combination of respiratory viruses ranging from Covid-19 virus, swine flu (H1N1), H3N2, and the seasonal Victoria and Yamagata lineages of influenza B viruses in circulation.

H3N2 and H3N1 are both types of influenza A viruses, commonly known as the flu. Some of the most common symptoms include prolonged fever, cough, running nose, & body pain. But in severe cases, people may also experience breathlessness and/or wheezing.

In addition, Covid is also on the rise. More than 700 Covid-19 cases were recorded in a day after a gap of over four months, taking the active caseload to 4,623, according to Union Health Ministry data updated on Thursday.

Health experts note that it is very difficult to differentiate between the clinical manifestations of the three, and the differentiation is generally based on a laboratory diagnosis from a nasopharyngeal swab sample.

"The only difference is that in the present clinical scenario, Covid symptoms barely last for 2-3 days and the patient recovers soon without any hassles and any major treatment," Dr. Samrat Shah, Senior Consultant, Internal Medicine, Sir HN Reliance Foundation Hospital told IANS.

"Whereas with H3N2 and H1N1 has more predilection for productive and wet coughs which lasts longer for a few weeks and has more chances of getting pneumonia or a secondary bacterial infection," Shah added.

As per Dr Sanjith Saseedharan, Consultant & Head-Critical Care, S.L. Raheja Hospital, Mahim, there is "an increase in throat irritation and hoarseness of voice among people affected with H3N2, which goes on for two to three weeks".

"Those diagnosed with Covid19 are generally manifesting a stuffy nose and a fever that lasts for three to four days," he told IANS.

Influenza is not fatal. But irrespective of the virus if there is a major comorbid factor there are more chances of morbidity and mortality. The risk is also high for young children, infants, adults with comorbidities, elderly people over the age of 65 years, patients who are pregnant, patients who are immunocompromised, etc.

The total number of deaths due to H3N2 in the country has now reached nine, according to media reports. The Health Ministry, however, is yet to release the official death toll.

On the other hand, a total of 754 new Covid cases were reported in a span of 24 hours, while the death toll has increased to 5,30,790 with one fatality reported by Karnataka, as per the Health Ministry data updated at 8 a.m. on Thursday.

The doctors stated that coupled with the changing weather, pollution is also playing a pivotal role in multiplying the patient numbers impacted by viral infections.

"Some of the environmental factors contributing to the increase in cases are poor air quality and excessive construction pollution. The only way to prevent this influenza virus complication is by vaccinating once a year with the quadrivalent flu vaccine," Shah said.

The health experts advised people to follow Covid appropriate behaviours such as using masks, maintaining hand hygiene and avoiding crowded places. They also stressed on the need for an annual flu shot.

"Annual flu shot of influenza would help in preventing the disease or at least the severity of the disease even if you do contact the disease. Unfortunately, the influenza vaccine nation coverage in India is not adequate which might actually explain the rising cases of this particular virus all across," Dr. Umang Agrawal, Infectious Diseases Consultant from PD Hinduja Hospital & MRC, Mahim, said.

Is your cough, fever due to H3N2 virus or Covid?