Vaccine linked to lowering risk of Alzheimer’s by 55 per cent

A vaccine has been associated with ‘significantly lower’ dementia risk among the elderly. A substantial observational study published in Neurology discovered that receiving a high-dose flu jab is linked to a reduced risk of Alzheimer’s disease in adults aged 65 and above.

The research was conducted by scientists at the McGovern Medical School at UTHealth in Houston. In the UK, there are presently an estimated 982,000 people living with dementia, according to the Alzheimer’s Society, projected to reach 1.4 million by 2040 , reports the Mirror.

In the retrospective cohort study, entitled ‘Risk of Alzheimer Dementia After High-Dose vs Standard-Dose Influenza Vaccination‘, researchers examined health data from approximately 165,000 older adults who received either a high-dose or standard-dose influenza vaccination. They discovered that the high-dose vaccine decreased the risk of Alzheimer’s disease in those 65 and above by nearly 55% over roughly a two-year timeframe.

Earlier findings by the same research team demonstrated that the standard-dose vaccine was linked to a 40% reduced risk over a four-year timeframe. The high-dose influenza vaccine contains four times the antigen, which is the element that triggers an immune response, of the standard-dose alternatives. The study’s authors propose that the « enhanced [flu vaccines] confer greater protection against influenza infection ». They add: « Thereby decreasing risk of severe illness and the associated systemic inflammation that can promote neuroinflammation and neurodegeneration ».

Reflecting on the findings, the researchers also stated: « High-dose influenza vaccination is associated with reduced AD risk compared with standard-dose vaccination in adults ≥65 years, with a stronger effect among women. This study provides Class II evidence that treatment with H-IIV vs S-IIV was associated with decreased incident dementia in individuals ≥65 years of age captured in this US health care claims database. »

While both men and women demonstrated a reduced risk of Alzheimer’s following the high-dose flu vaccine compared with the standard-dose alternative, the protective benefit appeared more consistent and endured longer in women.

The study’s advantages include its substantial sample size and its methodology, which compared vaccinated cohorts. The researchers acknowledged limitations, including « healthy-user bias », the likelihood that people who pursue high-dose vaccines also engage with health care in ways that influence dementia risk, and dependence on claims data that may have incorrectly classified Alzheimer’s disease.

The researchers say additional studies are needed to better understand vaccine dosage, immune responses, and long-term cognitive outcomes. Further investigation is also needed to establish whether vaccination might affect disease progression once symptoms have emerged.

In England, over 18.2 million patients registered with a GP were recorded as having received the flu jab during the 2024 to 2025 season. As of late November 2025, uptake figures showed that 70% of people aged 65 and over, 42% of expectant mothers, and 71% of care home residents were vaccinated.

Who should have the flu vaccine?

According to the NHS, the flu jab is recommended for people in the UK who face a greater risk of severe illness from flu. It’s provided on the NHS annually in autumn or winter. You can get the free NHS flu vaccine if you:

• are aged 65 or over
• have certain long-term health conditions
• are pregnant
• live in a care home
• are the main carer for an older or disabled person, or receive a carer’s allowance
• live with someone who has a weakened immune system

Frontline health and social care workers can also receive a flu vaccine through their employer.

Symptoms of Alzheimer’s disease and what causes it?

According to the NHS, Alzheimer’s disease is the most common cause of dementia in the UK. It says: « Dementia is the name for a group of symptoms associated with an ongoing decline of brain functioning. It can affect memory, thinking skills and other mental abilities. The symptoms of Alzheimer’s disease progress slowly over several years. Sometimes these symptoms are confused with other conditions and may initially be put down to old age. » In the initial stages, the primary indicator of Alzheimer’s disease is memory loss. For instance, someone with early-stage Alzheimer’s disease may:

As Alzheimer’s disease advances, memory difficulties will deteriorate. Additional symptoms may also emerge, such as:

• forget about recent conversations or events
• misplace items
• forget the names of places and objects
• have trouble thinking of the right word
• ask questions repetitively
• show poor judgement or find it harder to make decisions
• become less flexible and more hesitant to try new things

The conduct of those living with Alzheimer’s disease can also alter. For example, they may:

• increasing confusion and disorientation – for example, getting lost, or wandering and not knowing what time of day it is
• obsessive, repetitive or impulsive behaviour
• delusions (believing things that are untrue) or feeling paranoid and suspicious about carers or family members
• problems with speech or language (aphasia)
• disturbed sleep
• changes in mood, such as frequent mood swings, depression and feeling increasingly anxious, frustrated or agitated
• difficulty performing spatial tasks, such as judging distances
• seeing or hearing things that other people do not (hallucinations)

A range of further symptoms may also manifest as Alzheimer’s disease progresses, such as:

• be aggressive, such as hitting or shouting
• become upset or restless
• call out or repeat the same question again and again

A number of other symptoms may also develop as Alzheimer’s disease progresses, such as:

• difficulty eating and swallowing (dysphagia)
• difficulty changing position or moving around without assistance
• weight loss – sometimes severe
• unintentional passing of urine (urinary incontinence) or stools (bowel incontinence)
• gradual loss of speech
• significant problems with short and long-term memory