This informal CPD article ‘Vaccines and Surprising Health Benefits: What Recent Research Reveals About Heart Health, Brain Protection, and Beyond’ was provided by Cima Care, who offer extensive training in vaccination and public health, advancing global health initiatives.
"I thought vaccines just prevented infections." "Can a vaccine really protect my heart?" "Is there a connection between vaccination and dementia prevention?" These are the type of questions that reflect a fascinating shift in our understanding of vaccination. While vaccines have long been celebrated for preventing infectious diseases, 1 recent studies reveal something remarkable: the benefits of vaccination may extend far beyond their primary targets, offering unexpected protection for the heart and brain and even enhancing certain cancer treatments.
Vaccines and Heart Health: An Unexpected Connection
Flu Vaccination Protects Your Heart
Research has found a fascinating connection between flu vaccination and heart health. In a study of 218 people with existing heart disease, those who received the flu vaccine during flu season had dramatically lower odds of having another heart attack, about 67% lower than those who were not vaccinated.
Why does this happen? When you get the flu, the infection triggers several processes that can harm your heart: it increases inflammation in blood vessels, makes your blood more likely to clot, and puts metabolic stress on your cardiovascular system. By preventing the flu infection in the first place, vaccination stops these harmful cascades before they can damage your heart. 2
Broader Heart Benefits in Older Adults
The heart-protective effects extend beyond just preventing heart attacks. An extensive study following seniors (65 years or older) over six flu seasons found that vaccination was associated with:
- 27% fewer hospitalisations for heart failure
- 39% fewer hospitalisations for pneumonia
- 32% fewer hospitalisations for all breathing problems
These benefits applied to all seniors, regardless of their risk of heart problems, and even resulted in about $73 in cost savings per vaccinated senior. 3
Shingles Vaccine and Cardiovascular Events
A new global review examining shingles vaccination and heart health found that vaccination reduced the relative risk of cardiovascular events by 16-18% in adults. Because cardiovascular events are relatively uncommon in the general population, this percentage reduction translates to preventing 1.2 to 2.2 heart attacks or strokes per 1,000 vaccinated individuals each year, a small but influential absolute benefit.
Shingles occur when the virus that causes chickenpox reactivates from its dormant state in the nervous system, affecting about one in three people during their lifetime. The reactivated virus can invade blood vessels in the head, causing inflammation and vascular damage that may lead to stroke. By preventing the virus from reactivating, vaccination protects your blood vessels. 4
RSV Vaccine: Protecting Heart and Lungs Together
A major study of more than 131,000 adults aged 60 and older found that the respiratory syncytial virus (RSV) vaccine reduced hospitalisations for heart and lung problems by about 10%. This translates to preventing roughly 3 hospitalisations per 1,000 vaccinated individuals each year.
Importantly, this benefit applied to everyone in the study, regardless of whether they already had heart problems. The vaccine creates a chain of protection: first, it prevents RSV infection; by stopping the infection, it prevents severe breathing difficulties; and by preventing breathing difficulties, it stops the dangerous strain on the heart and lungs that leads to emergency hospitalisation. 5
The Dementia-Vaccination Connection: Protecting Your Brain
A surprising discovery concerns the link between vaccination and brain health. Multiple studies using sophisticated research methods have found strong associations between certain vaccines and reduced dementia risk.
Shingles Vaccine: A 20% Reduction in Dementia Risk
A unique study compared people born just before and just after a specific date that determined vaccine eligibility. Since eligibility was based purely on birthdate, the groups were virtually identical except for vaccine access, allowing researchers to measure the vaccine's actual protective effect.
The findings were striking, getting the shingles vaccine lowered the 7-year chance of a new dementia diagnosis by about 20%. This study design was particularly smart because it avoided the "healthy user problem," the fact that people who choose to get vaccinated are often healthier to begin with.6 Similar research in Australia confirmed these findings, showing that shingles vaccination decreased dementia diagnoses by 1.8 percentage points over 7.4 years. 7
The Newer Shingles Vaccine Shows Even Better Results
When the shingles vaccination programme shifted from a live attenuated vaccine to a recombinant (protein‑based) vaccine around 2017, researchers used this transition as a natural experiment to compare dementia risk between the two vaccine types. The study found that receiving the recombinant shingles vaccine was associated with a 17% increase in dementia‑diagnosis‑free time over six years compared with the older live vaccine. Among people who eventually developed dementia, this corresponded to an average of 164 additional days lived without a dementia diagnosis. The benefit was observed in both men and women, with the protective association reported as greater in women. 8
Flu Vaccination: Cognitive Preservation Through Multiple Pathways
Seasonal flu vaccination is increasingly discussed as a pragmatic strategy to lower dementia risk in older adults. A 2023 meta‑analysis of about 2.09 million adults found that vaccinated individuals had a 31% lower risk of developing dementia. In addition, a large Biobank cohort reported that vaccinated participants had a 42% lower risk, alongside a reduced risk of all-cause dementia and evidence of a dose–response relationship with the number of vaccinations. Multiple studies observed something important: the apparent protective association is stronger in people who receive influenza vaccines across multiple years and seasons, suggesting that regular annual flu vaccination may confer cumulative protection for brain health.
How might this work? Two main pathways are highlighted as ways through which influenza vaccination may help preserve cognition:
1. By preventing cardiovascular damage, since influenza infection sharply increases short‑term risks of heart attack and stroke, which accelerate vascular brain injury.
2. By dampening neuroinflammation, as experimental models show that even non‑neurotropic flu strains can trigger prolonged microglial activation, synapse loss, and memory decline, vaccination may help mitigate. 9
The Big Picture: Multiple Vaccines, Consistent Brain Protection
A massive systematic review of 21 observational studies, including over 104 million adults, examined the association between adult vaccination and dementia risk.
- Vaccination against shingles (herpes zoster) was linked to a 24% reduction in overall dementia risk and a 47% reduction in Alzheimer's disease, while
- Influenza vaccination was associated with a 13% lower risk of any dementia and an even more substantial reduction in vascular dementia risk.
- Tdap vaccination (tetanus–diphtheria–pertussis) was associated with a 33% reduction in overall dementia and a 42% reduction in Alzheimer's disease, and
- Pneumococcal vaccination was associated with a 36% reduction in Alzheimer's disease and a borderline significant reduction in any dementia.
The researchers' leading explanation centres on infection control and inflammation: by preventing infections, these vaccines appear to reduce systemic and neuroinflammatory burden, lessen infection‑related vascular insults, and may even 'train' innate immunity in ways that support clearance of harmful proteins such as beta‑amyloid involved in dementia. 10
COVID-19 mRNA vaccines can improve cancer outcomes
COVID-19 Vaccines: An Unexpected Ally in Cancer Treatment
Ground breaking research in 2025 revealed an unexpected finding: COVID-19 mRNA vaccines can dramatically improve outcomes in cancer immunotherapy.
What the Research Found:
Scientists studied lung cancer patients receiving immunotherapy (drugs that help the immune system fight cancer). Patients who happened to receive a COVID-19 mRNA vaccine within about 3 months of starting their cancer treatment lived significantly longer:
- With the COVID vaccine: Average survival of over 37 months (just over 3 years)
- Without the COVID vaccine: Average survival of about 21 months (less than 2 years)
- Difference: An extra 16 months of life, almost a year and a half longer
Similar benefits were seen in patients with advanced melanoma (skin cancer).
How Does a COVID-19 Vaccine Help Fight Cancer?
The mechanism, while complex, can be understood in steps:
Step 1: When you receive an mRNA vaccine, your body produces a powerful immune signal within 24 hours—think of it as a loud alarm that wakes up your entire immune system.
Step 2: This alarm activates special immune cells throughout your body, including inside tumours, making them much more alert and ready to identify threats.
Step 3: These activated immune cells don't just learn to recognise the COVID spike protein—they also start recognising cancer cells as dangerous. It's like training guard dogs to detect one specific scent, but they end up learning to detect several other threats at the same time.
Step 4: As immune cells attack the tumour, cancer cells try to defend themselves by displaying more "stop signs" that typically tell immune cells to back off. However, this backfires because cancer immunotherapy drugs work by blocking exactly these stop signs. So, by putting up more stop signs, the cancer actually makes itself a better target for treatment.
The COVID-19 mRNA vaccine essentially "jump-starts" the immune system, making cancer immunotherapy drugs work much better. This discovery was confirmed in both human patients and laboratory studies.11
Current Vaccination Recommendations
Health organisations continue to update vaccination recommendations based on the latest evidence:
- COVID-19 vaccines are recommended for people aged 6 months and older, with updated formulations authorised for the 2025-26 season.
- Flu vaccines are recommended for all people aged 6 months and older, as they protect against severe illness even when circulating virus strains differ from predictions.
- The RSV vaccine is recommended for all adults aged 75+ and for adults aged 50–74 at increased risk; for infants, either maternal vaccination or infant immunisation is recommended. 1
What This Means for You
These findings represent a significant shift in how we understand vaccination. While vaccines have consistently been recognised for preventing infectious diseases, research now shows they may offer broader health benefits, from protecting your heart and preserving cognitive function to potentially enhancing specific cancer treatments.
It is important to note that researchers are still working to fully understand these mechanisms. The studies show strong associations and plausible biological pathways, but more research is needed to confirm exact causal relationships in some cases.
If you are considering vaccination for yourself or family members, discussing these findings with your healthcare provider can help you make informed decisions based on your individual health circumstances and risk factors.
Key Takeaways
- Flu vaccination is associated with substantially lower risks of heart attack and heart failure hospitalisation, particularly in older adults.
- Multiple vaccines, including shingles, flu, pneumococcal, and Tdap, show consistent associations with reduced dementia risk in extensive studies.
- The shingles vaccine shows up to a 20% reduction in dementia diagnoses in studies designed to minimise bias.
- COVID-19 mRNA vaccines may enhance the effectiveness of certain cancer immunotherapies, though this is a very recent finding requiring further study.
- Vaccination recommendations remain focused on preventing serious infectious diseases, with these additional benefits representing potentially important secondary effects.
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REFERENCES:
1- CDC. Vaccination Trends [Internet]. Respiratory Illnesses. 2024. Available from: https://www.cdc.gov/respiratory-viruses/data/vaccination-trends.html
2- Naghavi M, Barlas Z, Siadaty S, Naguib S, Madjid M, Casscells W. Association of Influenza Vaccination and Reduced Risk of Recurrent Myocardial Infarction. Circulation. 2000 Dec 19;102(25):3039–45.
3- Nichol KL, Wuorenma J, von Sternberg T. Benefits of Influenza Vaccination for Low-, Intermediate-, and High-Risk Senior Citizens. Archives of Internal Medicine. 1998 Sep 14;158(16):1769.
4- New systematic review and meta-analysis shows an association between shingles vaccination and lower risk of heart attack and stroke [Internet]. Escardio.org. 2025. Available from: https://www.escardio.org/news/press/press-releases/New-systematic-review-and-meta-analysis-shows-an-association-between-shingles-vaccination-and-lower-risk-of-heart-attack-and-stroke/
5- Lassen H, Johansen ND, Christensen SH, Aliabadi N, Skaarup KG, Modin D, et al. Bivalent RSV Prefusion F Protein–Based Vaccine for Preventing Cardiovascular Hospitalizations in Older Adults. JAMA. 2025 Aug 30;
6- Eyting M, Xie M, Michalik F, Heß S, Chung S, Geldsetzer P. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature [Internet]. 2025 Apr 2;641:1–9. Available from: https://www.nature.com/articles/s41586-025-08800-x
7- Pomirchy M, Bommer C, Pradella F, Michalik F, Peters R, Geldsetzer P. Herpes Zoster Vaccination and Dementia Occurrence. JAMA. 2025 Jun 17;333(23):2083.
8- Taquet M, Dercon Q, Todd JA, Harrison PJ. The recombinant shingles vaccine is associated with lower risk of dementia. Nature Medicine [Internet]. 2024 Jul 25;1–1. Available from: https://www.nature.com/articles/s41591-024-03201-5
9- Blandi L, Del Riccio M. From breath to brain: influenza vaccination as a pragmatic strategy for dementia prevention. Aging Clinical and Experimental Research. 2026 Jan 16;
10- Damiano Pizzol, Gennaro FD. Association between vaccinations and risk of dementia: a systematic review and meta-analysis. Age and Ageing [Internet]. 2025 Oct 30 [cited 2025 Dec 11];54(11). Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC12636520/
11- Grippin AJ, Marconi C, Copling S, Li N, Braun C, Woody C, et al. SARS-CoV-2 mRNA vaccines sensitize tumours to immune checkpoint blockade. Nature [Internet]. 2025 Oct 22;1–10. Available from: https://www.nature.com/articles/s41586-025-09655-y
