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Delhi flu surge: Why is the fever higher, why are symptoms more severe?

The caseload has increased over the last two weeks, says internal medicine specialist Dr Suranjit Chatterjee.

Some flu viruses can get into the lungs, causing inflammation and fluid build-up. (Representational)

Runny nose, sore throat, coughing bouts, high fever, blocked sinuses, headache, swollen tonsils — the flu season is back with Delhi reporting a swamp of upper respiratory tract infections, with Influenza B and H1N1 (swine flu) cases predominating. Except this time, the symptoms are lasting longer, a week and 10 days even, and are accompanied by high grade fever.

According to Dr Suranjit Chatterjee, Senior Consultant, Internal Medicine, Indraprastha Apollo Hospitals, Delhi, “the symptoms are not only prolonged but require hospitalisation as well. The caseload, too, has increased over the last two weeks.” Dr Chatterjee is seeing even younger people, those between 35 and 40 years of age with severe body aches, persistent coughs and no improvement in conditions. “They are developing chest pain, secondary cough and acute restlessness, compelling them to seek hospital admission for better management even when they don’t require it,” he adds.

Are you seeing any specific strains?

There are more influenza B cases. This virus mostly infects humans, is less common than influenza A and mutates slowly. H1N1 (swine flu) is a subtype of the influenza A virus, which tends to have severe symptoms. During the 2009-10 flu season, a new H1N1 virus strain has been triggering infections.

What are symptoms of these viruses?

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Patients complain about high fever, sore throat, stuffy nose, body aches, headaches, chills, fatigue, diarrhoea, vomiting bouts and lack of appetite. Severe symptoms include pneumonia, respiratory failure, worsening of chronic medical conditions, pain or pressure in the chest or abdomen and sudden confusion.

Can influenza and swine flu cause pneumonia?

Some flu viruses can get into the lungs, causing inflammation and fluid build-up. This makes it harder to clear mucus, which becomes a host to bacteria, leading to secondary infection. The virus can also weaken the immune system, allowing bacteria to infect the lungs.

What’s the reason for the spike?

A known flu virus can seem more severe in certain years because it is constantly mutating. So our immune system, used to fighting earlier strains, is less effective against a new one.

Besides, environmental factors worldwide have changed and people are going from winter to a sudden spike in temperatures. People are shedding their warm clothing. So, whenever there is a change of temperature, there is a problem with acclimatisation. Besides, viruses multiply rapidly during temperature differences. Air pollution and pollen further accelerate viral transmission.

Who is at risk?

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Usually infection is self-limiting. If you have influenza B, the symptoms are prolonged but very few require hospitalisation. Rest, fluids and pain relievers are key. The same holds true for H1N1 although symptoms could turn severe among those with immuno-compromised conditions, co-morbidities, the elderly, children and pregnant women. This vulnerable group has landed up in our wards.

Do we need to get tested?

Everybody does not need to get tested. But if the symptoms worsen or are stubborn, get tested.

When to consult a doctor?

Whenever your symptoms persist and don’t improve. Do not take antibiotics as they won’t work on viruses. Wait for your doctor to give you antivirals if needed.

What about prevention?

Wear a mask, practise hand hygiene and avoid crowded places. Get a flu vaccine each year as it gets updated to fight a changing virus.