H3N2 Infection in Older People - Causes, Symptoms, and Treatment

What Is H3N2 Infection?

H3N2, also known as influenza A, is a subtype of the influenza virus and naturally infects humans. However, it can also infect pigs, dogs, and poultry. An outbreak of H3N2 occurred in various places in the United States in 2012. H3N2 infections were mostly found in people who were exposed to pigs for a long time. It is transmitted from pigs to humans and from humans to pigs. It is transmitted when a person inhales the droplets from the sneeze or cough of a pig. It can also be transmitted by touching things with viruses on them. If left untreated, it can lead to severe complications that may require hospitalization. Studies found that 70 to 85 % of deaths related to influenza occurred among people who are 65 years and older.

What Are the Symptoms of H3N2?

The symptoms of H3N2 are almost the same as symptoms caused by other influenza viruses:

• Cough: A dry cough that may last for several weeks is the most common symptom of H3N2 infection.

• High Fever: A high fever with a range of 100 to 104 degrees Fahrenheit that may last from a few days to weeks is another common symptom.

• Sore Throat: It is a common symptom in any type of viral infection.

• Runny Nose: The infected person may feel discomfort due to a runny or congested nose.

• Headache: Mild to moderate headaches can be present in people with influenza.

• Body Ache: Severe pain in the arms, legs, and back are also common.

Other symptoms are:

• Nausea and vomiting.

• Diarrhea.

• Chills.

• Fatigue.

Who Is at Higher Risk for Developing H3N2?

Anybody can contract H3N2 infection if exposed. But people who are at the risk for developing complications are:

• Children below the age of 5 years.

• People above the age of 65 years.

• Pregnant women.

• Adults who are obese or overweight.

• People with weakened immune systems due to any conditions or medications.

• People with conditions like heart disease, diabetes, asthma, etc.

• People who had strokes.

• People with kidney and liver disorders.

How Is H3N2 Diagnosed?

The physician will inquire about signs and symptoms along with previous medical history. However, the signs and symptoms can differ based on age, immunity, medical conditions, and medications taken by the patients. Following are the diagnostic tests for H3N2:

• Blood tests detect the presence of antibodies produced against viruses.

• Viral culture.

• Rapid antigen testing.

• Reverse transcription polymerase chain reaction (RT-PCR).

• Immunofluorescence assay.

• Rapid molecular assays.

• Rapid influenza diagnostic test (RIDT).

For the tests that analyze respiratory specimens, throat, nasal, and nasopharyngeal swabs are taken. Among these, nasopharyngeal have a better yield compared to others. Rapid influenza diagnostic tests can provide results within 15 minutes.

How Is H3N2 Infection Treated in the Older People?

Antiviral drugs, especially neuraminidase inhibitors such as Oseltamivir and Zanamivir, are the drugs usually prescribed to reduce the further replication of the H3N2 virus and improve the survival rate of patients. In addition, they can also reduce the symptoms associated with the infection. Experts suggest that it is better to provide these drugs within 48 hours after the symptoms show. Other antiviral drugs given are Peramivir and Baloxavir marboxil.

Treatment also focuses on managing symptoms such as dehydration managed by fluid administration. Oxygen supplementation is provided for patients with low oxygen saturation. Non-steroidal anti-inflammatory drugs (NSAIDs) are provided for relieving pain and fever.

What Are the Complications of H3N2 Infection in the Elderly?

The warning signs for complications in older people are shortness of breath, not urinating, seizures, pain in the chest and abdomen, severe muscle pain, weakness, confusion, etc.

• Pneumonia: Pneumonia is the most common complication of any type of influenza. The symptoms of pneumonia begin with shortness of breath. Low oxygen levels due to pneumonia present with bluish lips or face.

• Worsening of Existing Medical Conditions: H3N2 can make chronic conditions such as asthma, diabetes, heart disease, lung disease, low immune conditions, etc. worse, which can result in severe complications.

• ARDS: H3N2 can lead to acute respiratory distress syndrome or ARDS within several months if not treated. ARDS may cause respiratory insufficiency which can be fatal.

• Seizures: If the infection spreads to the brain, it can alter the brain chemistry that causes seizures or convulsions. This can also cause confusion, disorientation, delirium, etc.

• Hypoxemia: In severe cases of H3N2 infection, hypoxemia or low oxygen saturation occurs, resulting in symptoms like coughing, shortness of breath, chest tightness, chest pain, etc.

• Sepsis: H3N2 can turn into sepsis if not treated on time. The symptoms of sepsis after H3N2 are shivering, pale skin, confusion, extreme pain, shortness of breath, etc.

Is There a Specific Flu Vaccine for Older People?

Following are the specific flu shots recommended by the CDC (Centres for Disease Control and Prevention) and ACIP (Advisory Committee on Immunization Process) for people aged 65 years and above:

• Fluzone high dose quadrivalent inactivated influenza vaccine.

• Flublok quadrivalent flu vaccine.

• Fluad quadrivalent vaccine.

Pain, redness, or swelling at the injection site, headache, and muscle pain are the common side effects of H3N2. People who are 65 and above are also advised to take the pneumococcal vaccine on time as it is the main complication of influenza. Annual vaccination for influenza is very important as the strains of influenza viruses are changing every year. Hence, getting a flu shot annually gives the best protection against influenza by reducing complications and preventing hospitalizations.

How Can Older People Prevent H3N2 Infection?

Older people have to take extra care in preventing H3N2 as they come under a high-risk group for developing complications.

• Wash hands frequently with soap and water along with proper drying of hands.

• Get the flu vaccine every year.

• Avoid close contact with sick people.

• Cover mouth and nose while coughing and sneezing.

• Always wear a mask and avoid going to public places unless it is necessary.

• Avoid shaking hands and interacting closely with people as some may be asymptomatic.

• Drink plenty of water.

• Don't take medications without a prescription from a physician.

Conclusion:

H3N2 outbreak can put older adults at risk. If not treated on time, H3N2 can result in severe complications. So, it is important to get checked if any signs or symptoms of H3N2 infection appear. People who are 65 and above are advised to get annual shots for influenza as well as pneumonia to prevent the disease and complications associated with it to lead a healthy life.