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 per cent of influenza-related deaths and 50 to 70 per cent of influenza-related hospitalisations occur among those aged 65 years and older.
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 per cent are wrong about the ability of influenza to cause serious complications.
- 50 per cent did not know that up to 85 per cent of influenza-related deaths occurred in people aged 65 years and older.
- 57 per cent 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, namely Prof Dr Tan Maw Pin, consultant geriatrician, president of the Malaysian Society of Geriatric Medicine (MSGM), and member of Malaysian Influenza Working Group (MIWG), Dr Aslannif Roslan, internal medicine specialist and cardiologist at Institut Jantung Negara (IJN), and Assoc Prof Dr Lim Lee Ling, head of the Diabetes Care Unit and senior consultant endocrinologist, University of Malaya Medical Centre.
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.
What are the long-term effects in older persons after influenza infection?
Prof Dr 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.
Do you recommend the flu vaccination for older persons? If so, why?
Prof Dr Tan: Yes, the annual influenza vaccination is recommended for individuals aged more than 60 years, particularly those with chronic medical conditions or residing in aged care facilities (ACFs).
Can influenza really trigger a heart attack?
Dr Aslannif: Yes, influenza can cause or worsen existing heart disease. A bad case of influenza – such as one that is complicated by pneumonia – can worsen your existing heart disease. Even those without heart disease but have the risk factors (such as old age, smoking, and type 2 diabetes) are at greater risk of developing a heart attack because of influenza. The risk is also higher if you have underlying chronic diseases. Recent studies have shown that the risk of heart attack increases by more than 10 times in the first 7 days after contracting influenza.
What is the connection between severe influenza and the heart?
Dr Aslannif: Influenza can result in severe pneumonia which causes a reduction of oxygen levels in the arteries. This in turn results in a reduced oxygen supply to the heart muscle. At the same time, the fever and increased heart rate caused by influenza further increase the metabolic needs of your body leading to a greater demand for oxygen by the heart.
Influenza can also trigger an inflammatory response so great that it may cause rupture of atherosclerotic plaques, which is the build-up of fat, cholesterol, and other substances in the arteries, and it may also cause inflammation of the heart muscle (myocarditis). The reduced oxygen levels and rupture of atherosclerotic plaque can trigger a heart attack.
Do you recommend the influenza vaccination to your patients? If so, why?
Dr Aslannif: I recommend the annual influenza vaccination to all my patients. If you get the influenza vaccination every year, it can reduce your risk of developing a heart attack.
How does influenza impact a patient who has diabetes?
Assoc Prof Dr Lim: Diabetes is a well-known risk factor for serious influenza infections. When you get influenza, the body releases stress hormones as part of its defence mechanism to fight off the infection. As a result, more glucose is released into the bloodstream.
Eating less than usual and being dehydrated due to being sick could further disrupt your blood glucose control. This in turn can worsen diabetes-related complications such as abnormal kidney function, heart failure, stroke, and heart attack. These patients are also at a higher risk of developing pneumonia, often resulting in prolonged hospitalisation.
In addition, studies have shown that there is a greater risk of becoming admitted following an influenza infection with a three times higher risk of death in patients with diabetes.
Why are patients with diabetes more likely to develop influenza related complications such as pneumonia?
Assoc Prof Dr Lim: Normally, your body’s immune system would detect an invading offender such as the influenza virus, work its way to remove it and produce antibodies in the process. In patients with diabetes however, this mechanism is flawed. Inefficient blood sugar control also causes small blood vessel changes in the lungs in patients with type 2 diabetes.
In addition, continuous exposure to high blood sugar levels leads to formation of harmful compounds which are involved in the development of vascular complications, worsening of inflammation, and scarring of lung tissue.
Many times, patients with diabetes get admitted for pneumonia due to influenza, especially among those with either poorly controlled diabetes or concomitant chronic conditions. Some even require admission into the intensive care unit (ICU).
If my diabetes is well controlled, I won’t develop severe influenza-related complications, right?
Assoc Prof Dr Lim: Optimum control of blood sugar levels is extremely important to prevent complications. Compared to those without diabetes, patients with diabetes are at a higher risk of developing prolonged illness, hospitalisation, and even death caused by influenza, even though diabetes is well managed.
This is why both international (American Diabetes Association, World Health Organization, International Diabetes Federation) and local professional societies recommend all patients with diabetes aged 6 months and above receive the annual influenza vaccination. Notably, influenza is preventable, and its vaccination can reduce diabetes-related hospital admissions and death.
According to Prof Dr Zulkifli Ismail, technical committee chairman of the Immunise4Life programme, the Ministry of Health recommends the annual influenza vaccination to protect against influenza among older persons.
“Influenza vaccination has a good safety record. The side effects are generally mild, and these include soreness, redness and/or swelling at the injection site, headache, fever, and muscle aches, all of which will go away on their own after a few days.
“It is also advisable to wash your hands properly, avoid contact with those having influenza symptoms and disinfect frequently touched surfaces,” he said.
Make influenza prevention one of the proactive ways to improve the quality of life in your golden years.
This article is issued by Immunise4Life, a community education programme by the Ministry of Health, Malaysian Paediatric Association, and the Malaysian Society of Infectious Diseases and Chemotherapy. Click here for more information.
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