Ageing and Immunity: The vital role of vaccinations

As life expectancy climbs globally, so does the likelihood of encountering chronic conditions such as diabetes and cardiovascular diseases. With ageing, our susceptibility to these ailments rises, adding strain to our immune system.

This complex system shields our bodies from infections, diseases, and harmful substances. Yet, as time progresses, the immune system undergoes substantial changes, altering its functionality and efficacy. These transformations bear crucial implications for the health and well-being of older adults.

What are the implications of an ageing immune system?

To name a few, a gradual deterioration of the immune system can lead to:

  • a reduced ability to respond to new infections
  • increased susceptibility to certain diseases (such as respiratory infections),
  • a higher risk for chronic diseases and
  • a decline in the effectiveness of vaccinations.

What are the processes involved in a declining immune system?

The main changes happen in the composition and function of immune cells, alterations in immune signalling and reduced production of antibodies. This leads to a decline in the body’s ability to mount an effective immune response.

Will ageing have the same reaction in all of us?

No. It is, therefore important to note that the ageing process is highly variable. Genetics, lifestyle factors, and overall health significantly determine an individual’s immune function in later life.

What is the role of vaccinations?

Vaccinations play a vital role in public health by preventing the spread of infectious diseases and protecting individuals and communities from potentially severe and life-threatening illnesses.

How do vaccines work? 

Vaccines are designed to stimulate the immune system to produce an immune response against specific pathogens, such as bacteria or viruses. They mimic the mechanism of an infection to elicit an immune response. This helps the body recognise and fight off these pathogens more effectively. Vaccines have been instrumental in eradicating or significantly reducing the incidence of many deadly diseases, such as smallpox, polio, and measles.

Do all individuals respond the same way to vaccinations?

Older individuals occasionally have a reduced response to vaccinations compared to younger people. To address this, some vaccines targeted at older adults include higher antigen doses or adjuvants (substances that enhance the immune response). A study published in January 2023 showed that older adults required multiple COVID-19 vaccination doses to generate the same response as younger individuals. However, the safety of administering vaccinations to older adults remains the same as with everyone else.

Why is it important to get as many people as possible vaccinated?

When a sufficient portion of a population becomes immune to a disease through vaccination, a phenomenon known as herd immunity occurs. This provides indirect protection to vulnerable people, e.g., older adults and infants, and individuals who cannot receive vaccines due to medical reasons. Herd immunity helps prevent the rapid spread of diseases, reducing the overall burden of infections in a community.

Why would an elderly individual get vaccinated despite the risk of still falling sick?

Even if a vaccinated individual contracts a disease, they are often protected from severe illness due to the immune response generated by the vaccine. This can prevent hospitalisations, complications, and deaths associated with the disease.

A good example is the influenza or flu vaccine. A 2021 study showed that among older adults hospitalised with the flu in the United States, vaccinated patients had a 26% lower risk of intensive care unit (ICU) admissions and a 31% lower risk of death from the flu compared to those who were unvaccinated.

Similarly, the shingles vaccine (Shingrix) 91% effectively prevents the disease in adults 70 years and older. In this same age group, the vaccine is 89% effective in preventing post-herpetic neuralgia (PHN) – a complication of shingles that causes lasting pain in the area of the skin & nerves where the rash was previously. PHN can lead to debilitating symptoms the older we get, including trouble sleeping, tiredness, chronic use of painkillers and even depression.

Why do some vaccinations cost more than others?

Advances in vaccine technology have led to the development of new and more effective vaccines. Modern vaccine development involves a combination of scientific research, innovation, and rigorous testing to ensure safety and efficacy.

It is important to note that vaccinations are generally cost-effective in the long run. The economic burden of treating diseases and addressing their long-term effects can be far greater than the cost of implementing vaccination programs.

Which vaccinations are highly recommended in older adults?

  • Flu vaccine (quadrivalent) given every 6 to 12 months
  • Pneumococcal vaccine as a single dose (PCV 20) or two doses (PCV 13 followed by PPSV 23 a year later)
  • Shingles vaccines. Two doses given 2 to 6 months apart
  • Tdap (tetanus, diphtheria, pertussis) booster every ten years
  • COVID-19 boosters according to local advisories and guidelines

In conclusion, immune system function begins to decline naturally in middle-aged individuals. The prevalence of chronic diseases and infections further diminishes immunity.

Vaccinations, hence, are a cornerstone of public health efforts to prevent the spread of infectious diseases, reduce disease burden, and protect especially vulnerable individuals like older adults.

If you’d like further information on any of the vaccinations mentioned above, head over to our patient education section or contact us today to schedule an appointment to learn more.

Dr Vinu Sahlen

Family Physician

Languages: English, German, Swedish

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