How Is Influenza in the Elderly Different from Influenza in the General Population?

Influenza, commonly known as the flu, is a contagious respiratory disease that frequently spreads during the rainy season. Common symptoms include fever, coughing, and body aches. For most people, these symptoms subside within 3-5 days without any serious consequences. However, for the elderly or those with underlying conditions like chronic obstructive pulmonary disease (COPD), asthma, heart disease, stroke, chronic kidney disease, or diabetes, the flu poses a higher risk of severe complications, sometimes requiring hospitalization. In Thailand, the highest rates of flu-related hospitalizations are seen among young children and the elderly.

Why Is Influenza More Dangerous for the Elderly?

Flu infections in older adults can lead to serious health complications beyond just the flu itself:

• 8 times higher risk of stroke compared to the general population.
• 10 times higher risk of heart attack compared to the general population.
• 23% of elderly flu patients may lose their ability to take care of themselves after recovery.
• 75% of diabetic patients may experience abnormal blood sugar levels during a flu infection.

In fact, 4 out of 10 patients who suffer acute heart attacks due to flu infections are elderly. Flu infections can cause heart disease to worsen, lead to sudden heart attacks, and even cause fatty deposits in blood vessels to rupture, leading to dangerous blood clots. Sudden heart attacks due to flu complications are also a significant cause of death.

Why Are Older Adults More Vulnerable to Flu-Related Complications?

1. Weakened Immune System (Immunosenescence): As we age, our immune system becomes less responsive, which is why older adults have a weaker response to vaccines. This makes them more susceptible to infections, including the flu.
2. Chronic Underlying Conditions: Elderly people often have long-term health conditions like heart disease or chronic lung disease, which can increase the severity of the flu and lead to higher mortality rates when both conditions are present.
3. Frailty: Many elderly people are frail, which further weakens their ability to fight infections. Flu combined with frailty can lead to disability, causing a greater need for assistance in daily living. Those with multiple underlying conditions are especially vulnerable to severe flu complications and tend to respond poorly to flu vaccines.

Can the Flu Be Prevented?

The good news is that influenza can be prevented by getting an annual flu vaccine. Since the flu virus changes each year and new, more severe strains emerge, the vaccine is updated annually to match the circulating strains. While you can get the flu vaccine any time during the year, the best times to get vaccinated are before the rainy season (May) and before winter (October), as this is when flu outbreaks typically begin.

Benefits of Flu Vaccination:

• 34% reduction in major cardiovascular events.
• 45% reduction in acute coronary syndrome.
• 56% reduction in cardiovascular-related deaths.

Recently, high-dose flu vaccines have been developed specifically for the elderly, offering better protection against flu infections. These vaccines have been shown to significantly reduce hospitalizations from flu-related complications like pneumonia and respiratory infections.

The high-dose flu vaccine has been used for over 10 years, with more than 202 million doses administered in over 35 countries. Studies show that the high-dose flu vaccine can reduce hospitalizations due to flu or pneumonia by 64.4% and reduce mortality by 48.9% in elderly patients. Because of these benefits, high-dose flu vaccines are now recommended for older adults as they provide greater protection than standard-dose vaccines.

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