Following a massive surge in cases of influenza A H3N2, there has been an alert in Delhi-NCR. Reportedly, hospitals across Delhi have been witnessing increasing ICU admissions of persons with suspected H3N2 infections.
On March 10, Union health minister Mansukh Mandaviya held a meeting to review rising cases of the H3N2 influenza virus in the country. “Advisory issued to states to be on the alert and closely monitor the situation. Government of India is working with states & extending support for public health measures to address the situation,” he tweeted.
Prior to this, the Indian Council of Medical Research (ICMR), a wing of the Indian health ministry, had said that the H3N2 virus is responsible for the recent surge in cases of fever and respiratory illnesses in India. This is based on the surveillance data from mid-December to March 3. H3N2 is a subtype of influenza A (flu virus).
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The typical symptoms of H3N2 viral infection include fever, chills, prolonged cough and sneezing. Among those hospitalised with the H3N2 infection, 92 per cent had a fever, 86 per cent had a cough, 27 per cent suffered from breathlessness and 16 per cent had wheezing, ICMR said in its tweets.
“There are very few cases of severe infections. About five per cent of the admitted cases have a severe infection. The typical signs are high fever, prolonged cough and body pain. Some have diarrhea,” says Dr VR Yamunadevi, an infectious disease specialist at Apollo Hospitals, Chennai.
Dr Yamunadevi has observed that from October to December of 2022, a majority of the flu cases were caused by influenza A H1N1, whereas in the last two months (since January 2023), the cases are more due to the H3N2 subtype. When compared to the H1N1 variant, H3N2 is marked by higher fever, prolonged cough and chills.
Tests confirm H3N2 infection spread
A respiratory viral panel (RVP) test can detect different types of viruses, including influenza and covid-19. In this test, a nasopharyngeal swab (collecting the secretions from the back of the nose and throat) is taken.
“The results show that H3N2 is circulating and covid is not seen,” says Dr Yamunadevi.
Dr Ankita Baidya, infectious disease specialist, Manipal Hospital, Dwarka, New Delhi, says that only those with a severe infection and those likely to develop a severe infection are being currently tested.
Short incubation period and fast spread
Influenza viruses tend to cause both upper respiratory (URI) and lower respiratory tract infections (LRTI). “The variant influenza A H1N1 has the tendency to cause pneumonia than the H3N2 variant. The bad thing about influenzas is that it is highly contagious, the virus multiplies in the nose and throat and spreads very fast. The incubation period is just two days. Along with the clinical symptoms, multiple family members catching the infection in one or two days is also seen,” says Dr Baidya.
In the majority of the flu-like cases that Dr Baidya has seen, he says families point out that it is the children who get the symptoms first, hinting that it could be spreading among schoolgoing students.
Mask compliance helped control flu
While the typical flu season in India is between October and December, in the current viral cycle it has extended to more than four months, observes Dr Yamunadevi.
“In the last two years, there were hardly cases of influenza as mask compliance was there and crowding was controlled. In 2022-23 people are moving around and going out, and there is no mask compliance. Hence there are flu viruses in circulation. Of all the viruses, what we have predominantly seen is H3N2,” says Dr Yamunadevi.
Dr Baidya adds that H3N2, being a subtype of influenza A, is not a mild infection. “Of influenza A, B and C variants, it’s influenza A that causes serious infections like pneumonia.”
IMA warns against self-medication
The Indian Medical Association’s standing committee for anti-microbial resistance issued an advisory on March 3. The medical body has warned against self-medication through antibiotics as it can lead to antibiotic resistance. “It is necessary to diagnose whether the infection is bacterial or not before prescribing antibiotics. It is common to have a seasonal cold or cough during October to February period, because of influenza and other viruses. Give only symptomatic treatment and no need to give antibiotics,” the advisory reads.
On March 6, the Karnataka government issued a circular directing hospitals to ensure regular surveillance of influenza-like illness (ILI) and severe acute respiratory illness (SARI). It further suggested appropriate sample collection for diagnosis and reporting of such cases to the government portal. The Karnataka health commissioner also directed health centres to ensure sufficient stock of oseltamivir antiviral drugs and personal protection equipment for health workers.
Doctors suggest influenza vaccination
Those on chemotherapy, dialysis and people suffering from comorbidities and chronic illnesses are vulnerable to severe infections due to H3N2, say doctors. They point out that the influenza vaccination could be a precautionary measure. Dr Baidya advises all pregnant women to take the influenza vaccination.
Though vaccination cannot prevent infection, it can reduce the severity of infection. Dr Yamunadevi says that anybody above the age of six months must take the influenza vaccination annually. “I suggest influenza vaccination because of late we haven’t seen a flu season that has extended beyond four months,” she says. The jab is a necessity for healthcare workers to prevent infections.
How to ensure self-care during the flu season
- Wearing masks can help contain the infection.
- Hand hygiene is important.
- If you have a fever, paracetamol can be taken as an immediate measure. Consulting a doctor is a must.
Takeaways
The Indian Council of Medical Research has pointed out that influenza A subtype H3N2 infections are in circulation. The symptoms range from fever to breathlessness. A viral panel test which can detect the infection is currently done in people with severe symptoms and those who need hospitalisation. Doctors say that wearing masks can help control the infection; doctors also warn against self-medication.
