Dr. Ch. Manoj Kumar

Consultant - General Physician

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Dr. Ch. Manoj Kumar

Consultant - General Physician

Manipal Hospitals, Vijayawada

H3N2 During Flu Season: More Learning About The Virus

Posted On: Mar 28, 2023

blogs read 5 Min Read

General Medicine Hospital in Vijayawada

The H3N2 is an influenza virus that is becoming more prevalent, according to recent reports. It has affected a sizable proportion of the population making them sick with respiratory conditions. 

The transmission of H3N2 influenza among the population has evolved with the rise of seasonal flu. It is a subtype of influenza A that is distinguished by its extremely infectious nature.

What is Influenza Virus?

The influenza virus, sometimes known as "the flu", causes contagious sickness resulting into influenza, affecting larger population. Its symptoms, which can range from mild to severe, include fatigue, headache, runny nose, sore throat, headache, and fever.

According to the best general medicine doctors in Vijayawada, influenza can lead to pneumonia in some cases, which can be caused by the virus directly or by a subsequent bacterial infection. Infection can also worsen the pre-existing medical disorders like asthma and cardiovascular disease, and causes meningitis, encephalitis, and acute respiratory distress syndrome.

Types of Influenza Viruses

The four variants of influenza viruses that are responsible for the contagious illness known as the flu are A, B, C, and D. The influenza B and C (IBV and ICV) viruses primarily affect humans. Cattle and pigs are infected with the influenza D virus (IDV). Influenza A is further subdivided into subtypes, one of which is H3N2.

What is H3N2?

The H3N2 influenza virus subtype (A/H3N2) is a type of influenza virus. This virus spreads through respiratory droplets produced when an infected person coughs, sneezes, or talks, and it is very contagious. This subtype is known to produce more severe disease than other flu viruses, especially in children and older people.

It is easily transmitted through contact with contaminated objects as the virus can survive on surfaces for several hours. The H3N2 virus can mutate, making it difficult for the body's immune system to recognise and combat the virus. This can result in flu outbreaks in communities or regions, especially during the winter months.

The H3N2 virus can also infect pigs, birds, dogs, and other animals along with humans. Depending on the animal species involved, the virus is referred to as either swine flu or avian flu when it affects animals. In rare cases, these viruses can spread from animals to people, causing flu outbreaks that have a serious negative impact on public health.

Symptoms of H3N2

Similar to other flu strains, the H3N2 influenza virus can cause more severe symptoms, especially in young children and older people. The symptoms often start to show up within 1–4 days after the viral infection and can persist for up to 7 days. The severity of the H3N2 virus's symptoms might vary from person to person, but typical symptoms include:

  • Fever (mainly with chills)

  • Cough

  • Muscle and joint pain

  • Sore throat

  • Runny nose

  • Headache

  • Nausea

  • Abdominal discomfort

Risk Factors for H3N2 Infection

Some high-risk populations are more exposed to this infection than others. Some of those groups of people include:

  • Pregnant women

  • Children below 5 years

  • Elderly population

  • People suffering from chronic medical conditions.

  • People who have undergone steroids, chemotherapy, or are suffering from immunosuppressive conditions.

  • Healthcare workers who are always in direct contact with the patients.

Mode of Action of H3N2

  • The H3N2 influenza virus spreads very rapidly, especially in crowded places, such as nursing homes, workplaces, transit hubs, and schools.

  • When an infected person sneezes or coughs, virus-containing droplets are released into the air; once airborne, the virus spreads up to a meter and easily infects those who are present at nearby places and breathe in the droplets. Physical contact can also cause the virus to spread. One could get the infection if they touch a contaminated surface or object.

  • The H3N2 influenza virus affects people all year in tropical countries like India, causing irregular outbreaks that are difficult to track. Seasonal influenza, on the other hand, is primarily seen in temperate regions with temperate climates during the winter.

H3N2 vs. Coronavirus

H3N2 influenza and COVID-19 are both caused by contagious viruses that can spread through droplets and significantly mutate. Some important facts regarding the same are discussed below:

  • Despite the fact that both of these respiratory infections are quite contagious, they are caused by viruses from distinct families.

  • H3N2 is a human-circulating subtype of the influenza A virus, whereas COVID-19 is brought on by the SARs-CoV-2 virus.

  • The incubation period for seasonal influenza may be considerably shorter than the COVID incubation period. It typically takes 1-4 days from infection to sickness.

Diagnosis of H3N2 Infection

Clinical testing is used to determine the majority of H3N2 influenza cases. A respiratory sample and a diagnostic test application in the lab will be needed to identify the pathogen's nature. 

The lab will confirm the presence of the H3N2 influenza virus in samples taken from secretions or washings from the nose, throat, trachea, and nasal passages. The collection process is carried out directly using antigen detection and viral isolation.

Rapid influenza diagnostic tests (RIDTs) are conducted in clinical settings like nursing homes, hospitals, or outpatient clinics. 

Treatment for H3N2 Infection

The treatment of H3N2 influenza at the top general medicine hospital in Vijayawada aims at managing the symptoms and avoiding the complications caused by the virus. Some of the treatment approaches are discussed below:

  • Antiviral Medications

Oseltamivir and zanamivir are sometimes used to treat H3N2 virus infections, particularly in people who are more likely to develop problems (elderly, young children, and those with weakened immune systems).

  • Taking Rest

It is important to get plenty of rest to help the body fight off the infection and recover.

  • Intake of Fluids

Drinking plenty of fluids like water, tea, and soup can help prevent dehydration and reduce symptoms like fever and cough.

  • Over-the-counter Medications

Ibuprofen and acetaminophen can be used to treat fever, headache, and other symptoms. The symptoms of a cough and nasal congestion may also be relieved by over-the-counter cough and cold drugs, although these should be taken with caution, especially in young children.

  • Oxygen Therapy

This therapy helps the body receive enough oxygen in severe cases.

Prevention from H3N2 Infection

The best defense against H3N2 virus infection is prevention. Some of the preventive measures include:

  • Getting vaccinated against the flu every year.

  • Regular washing of hands.

  • Covering the mouth and nose when coughing and sneezing.

  • Staying at home when sick.

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