The vaccines that matter after 65, and what they actually prevent

Immunosenescence is the gradual decline in immune function with age. Thymic output of naive T cells falls almost to nothing by later life, the repertoire of available responses narrows, antibody responses to new antigens weaken, and a background of low-grade chronic inflammation — sometimes called inflammaging — develops.

The consequences are twofold and both matter. Infections are more severe and more likely to be fatal. And vaccines work less well, generating lower antibody titres that wane faster.

This is not a reason to skip vaccination; it is the reason several vaccines exist in age-specific formulations.

Influenza

Influenza kills mostly older adults, and much of that mortality is indirect — the fortnight after an influenza infection carries a markedly elevated risk of myocardial infarction and stroke, an association demonstrated in self-controlled case series studies. The illness destabilises heart failure and COPD, and precipitates the functional decline from which many older people do not fully recover.

Standard-dose vaccine produces a weaker response in this group, so several enhanced formulations are used:

• High-dose vaccine, containing four times the antigen. A large randomised trial found it about 24 per cent more effective than standard dose in the over-65s.
• Adjuvanted vaccine, containing MF59 to boost the immune response.
• Recombinant vaccine, produced without eggs and with higher antigen content.

Which is offered depends on your country's programme. It is reasonable to ask which one you are getting.

Shingles

Herpes zoster is reactivation of the chickenpox virus that has been dormant in your sensory ganglia since childhood, and reactivation becomes more likely as cell-mediated immunity declines. Roughly one in three people will get shingles in their lifetime.

The acute rash is unpleasant. The reason to prevent it is postherpetic neuralgia — persistent nerve pain lasting months or years after the rash resolves, occurring in perhaps 10 to 18 per cent of cases and rising sharply with age. It is genuinely difficult to treat and can be severe enough to be life-changing.

The recombinant vaccine (Shingrix) is substantially better than the older live vaccine, with efficacy above 90 per cent against shingles in trials, sustained well into the years afterwards, and it can be given to immunocompromised people for whom a live vaccine is contraindicated. It is two doses, and the second dose is more reactogenic than most vaccines — a day or two of feeling genuinely unwell is common and is not a reason to skip it.

Pneumococcal disease

Streptococcus pneumoniae causes pneumonia, bacteraemia and meningitis, and incidence and case fatality both rise steeply with age.

Two vaccine types exist. Polysaccharide vaccines (PPSV23) cover more serotypes but generate a weaker, non-memory response. Conjugate vaccines (PCV13, PCV15, PCV20) cover fewer serotypes but produce a stronger, longer-lasting response. Recommendations have changed repeatedly as newer conjugates with broader coverage have arrived, and current guidance in several countries has simplified to a single dose of a broad conjugate vaccine.

Because the schedules have shifted, this is one worth actively asking about rather than assuming your record is current.

COVID-19

Age remains the dominant risk factor for severe outcomes, by a very wide margin. Boosters in older adults continue to show benefit against severe disease and hospitalisation, with protection against infection waning considerably faster than protection against severe outcomes. Recommendations now generally follow a seasonal pattern for this age group.

RSV

Respiratory syncytial virus was long thought of as a paediatric problem. It causes a substantial burden of hospitalisation and death in older adults — comparable in some seasons to influenza — and is particularly dangerous in those with chronic heart or lung disease.

Vaccines became available for older adults from 2023 and have shown good efficacy against lower respiratory tract disease in trials. This is a genuinely new addition and many eligible people are unaware it exists.

Tetanus, diphtheria and pertussis

Immunity wanes. A booster every ten years is the usual recommendation, and older adults are the group most likely to be overdue. Pertussis vaccination also matters for grandparents in contact with infants too young to be vaccinated themselves.

Reasonable questions and reasonable answers

"I never get flu." Influenza vaccine reduces severity and complications as well as infection, and the cardiovascular protection in the weeks after infection is a real and under-appreciated benefit.

"It gave me flu last time." Inactivated vaccines cannot cause influenza. A day of aches and fatigue is an immune response, and in an older adult it is arguably a good sign.

"I'm on immunosuppressants." Live vaccines are generally contraindicated; inactivated and recombinant ones are usually recommended and often more important than in the general population. This needs individual advice.

"Too many at once?" Co-administration is generally safe and increases the chance the course is completed. Reactogenicity can be a little higher.

Take your record to your next appointment. Between influenza, shingles, pneumococcus, COVID, RSV and tetanus, most people over sixty-five are missing at least one, and shingles is usually the one.