As we know, advancing age makes us more susceptible to infectious diseases. The risk of developing severe disease is higher in the presence of non-communicable diseases (NCDs), also known as chronic diseases such as diabetes, heart disease, stroke, or chronic lung disease.

This was an important observation made during the time of the COVID-19 pandemic. Similar to COVID-19, older persons are at a higher risk of developing severe influenza, also known as the flu.

Influenza is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. Your body’s first response to influenza infection is known as acute inflammation occurring at the site of infection to limit or get rid of the virus.

If this response is insufficient, then a more complex immune response occurs at both the site of infection and in the entire body. This response is necessary to fight off infections, however, sometimes with influenza, this response might be excessive and here is where the DANGER lies.

Approximately 90% of influenza-related deaths and 50-70% of influenza-related hospitalizations occur among those aged 65 years and older.[i] Despite this, there are some important gaps that surround influenza.

The Immunise4Life secretariat recently ran a poll on social media to see just how ‘flu-ent’ (pun-intended) the older folk are on influenza. The 518 respondents had at least one chronic disease.

We found that many did not fully grasp the severity of influenza:

• 48% are wrong about the ability of influenza to cause serious complications.
• 50% did not know that up to 85% of influenza-related deaths occurred in people aged 65 years and older.
• 57% did not realise influenza can trigger a heart attack or stroke even without a history of heart disease.

Given the knowledge gaps, this article presents three experts to set the record straight. There is, Professor Dr Tan Maw Pin, consultant geriatrician, President of the Malaysian Society of Geriatric Medicine (MSGM) and member of Malaysian Influenza Working Group (MIWG). Then there is Dr Aslannif Roslan, Internal Medicine Specialist and Cardiologist from Institut Jantung Negara (IJN), and Associate Professor Dr Lim Lee Ling, Head of the Diabetes Care Unit and Senior Consultant Endocrinologist, University of Malaya Medical Centre.

Q1: Why are older persons at greater risk of developing severe complications from influenza?

Prof Dr Tan: There are changes that occur in the immune system that leads to a decline in the ability of the body to fight off infections such as influenza; this is known as immunosenescence. Besides this, there is something known as inflammaging which is a chronic low-grade, non-infectious inflammation. This reaction could aggravate existing medical problems or lead to strokes and heart attacks.

Q2: What are the long-term effects in older persons after influenza infection?

Prof Tan: Older persons who take to their beds for a few days lose muscle far quicker than younger people. We call this deconditioning. This may lead to an increased risk of falls and reduced mobility after a bout of influenza. Many of these older persons then struggle to regain their pre-illness physical condition.

Q3: Do you recommend the flu vaccination for older persons? If so, why?

Prof Tan: Yes, the annual influenza vaccination is recommended for individuals aged ≥ 60 years, particularly those with chronic medical conditions or residing in aged care facilities (ACFs).

[i] Influenza death and hospitalisations https://www.cdc.gov/flu/spotlights/2018-2019/hopitalization-rates-older.html