Dementia Vaccines - Efficacy and Newer Advancements

Introduction:

Dementia is a syndrome that manifests as progressive cognitive decline and is the seventh leading cause of death among all diseases. The primary risk factor for this is age, and the number of people living with the condition increases. More than fifty-five million people worldwide are suffering from dementia, and its prevalence doubles every two decades, with a total number of people with dementia reaching 139 million in 2050. Dementia not only adversely affects the physical and psychological well-being, ability to perform daily living activities, and quality of life of the individual but also has long-lasting negative effects on caregivers and families. The enormous burden makes dementia one of the greatest challenges to global health and social care in the 21st century.

What Is Dementia?

A group of symptoms connected to memory loss and a deterioration in cognitive function is referred to as dementia, which is a neurocognitive syndrome.

What Are the Risk Factors for Dementia?

The risk factors for dementia include:

• Hypertension.

• Diabetes.

• Hearing impairment.

• Excessive alcohol consumption.

• Smoking.

• Obesity.

• Depression.

• Head injury.

• Air pollution.

• Lack of physical activity.

• Infrequent social contact.

• Low level of education.

Any modifications in the above factor can prevent or delay the onset of dementia by forty percent. Other risk factors for dementia include sleep disturbances, sleep duration, marital status, vitamin D deficiency, and cardiovascular disease. A growing field of research suggests that the immune system and infections play a significant role in the development of dementia; bacterial, fungal, and viral infections may cause neurotoxic inflammation and oxidative stress in the brain, which can lead to neurodegeneration. In addition, many sources of inflammation, such as periodontal disease, may be involved in the development of dementia. Thus, vaccination, the most effective and affordable method to prevent and control infectious diseases, may positively affect dementia risk.

What Are the Importance of Vaccinations?

• For years, public health authorities have wanted to dispel the myth that vaccinated people are more likely to develop Alzheimer’s disease. This is because vaccination stimulates the immune system and thus causes inflammation, which is part of the pathology of Alzheimer’s disease. But a more important reason is that the occasional neuropsychiatric disorders occurring after vaccination are over-reported in the media as a cause-and-effect relationship to appeal to public sentiment.

• A previous meta-analysis has found a significantly lower risk of dementia after influenza vaccination, but this study did not further explore the factors that might influence this association. In addition, several studies have examined the association between other common vaccines, such as shingles, diphtheria, and tetanus vaccines, and the risk of dementia. Nevertheless, the current evidence on the association between vaccination and dementia risk is inconsistent, and there is a lack of studies that have comprehensively explored this topic; a meta-analysis was conducted, and a systematic review was done to investigate the effect of different vaccinations on dementia risk, taking into account the influence of age, sex, and dose.

• Dr. Heather Synder, vice president of medical and scientific relations for the Alzheimer’s association, has stated that in Alzheimer’s disease research, over 100 potential therapies are being tested at various stages of the research process, and many more are being developed. She explained that some studies have looked at using vaccines and other forms of active immunization to "protect" people from Alzheimer's. These vaccines are being created to focus on the biology associated with Alzheimer's.

• In some instances, they are utilizing biology from years of vaccine-related work more widely in medical care.

• According to the expert, several delivery methods and biological systems may be targeted by vaccination for potential therapy. According to Dr. Agadjanyan, dementia vaccines would trigger immunological reactions against pathogenic substances in the body linked to dementia, such as:

1. Beta-Amyloid Proteins: Alzheimer's disease is frequently associated with a toxic buildup of these proteins in the brain.

2. Tau: A protein that aids in stabilizing the interior structure of neurons in the brain.

3. Alpha-synuclein: A protein in neurons associated with Parkinson’s disease.

How Do Doctors Diagnose This Condition?

• Positron Emission Tomography: This scan helps in revealing the metabolic or biochemical functions of the tissues and organs. It uses a radioactive substance called radiotracers to visualize and measure changes in metabolic processes.

• Computed Tomography Scan: It is an imaging procedure that uses special X-ray equipment to create detailed images of the internal organs present in the body.

• Magnetic Resonance Imaging: This scan can reveal whether the brain has had general atrophy, which can be used in conditions like Alzheimer's disease, particularly atrophy around the hippocampus, the area of the brain in charge of various memory

functions.

So, to a certain extent, these brain scans can aid in the diagnosis of a specific brain disorder that is causing dementia. Still, it is vital to keep these facts in mind so that it can never be confirmed until after death.

Are There Any Vaccines Under Development?

A lot of vaccines are now in the phase of clinical trials to test their efficacy. They are as follows:

• A certain immunotherapeutic vaccine by Vaxxinity has been under trial for Alzheimer’s that has completed phase 1 and 2A of the trials and has also received a fast-track designation. Phase 2B is expected to begin in late 2022 or early 2023.

• A nasal vaccine for Alzheimer’s is in phase 1 of clinical trials. It is being tried and tested in Boston’s Brigham and Women’s Hospital.

• Another vaccine aiming the beta-amyloid 40, which plays a significant role in Alzheimer’s is under phase 2 clinical trials.

• A phase 1 clinical trial is in process for Swiss-based biopharmaceutical company AC Immune SA has a tau-targeted vaccine candidate for Alzheimer’s disease.

• According to Dr.Merrill, it will take some time before any immunizations are made accessible to the public.

He noted that any vaccine will still take several years to pass through the development process, the regulatory barriers, and the phases of clinical testing. According to Dr. Snyder, the research conducted thus far could have been much higher. Before commenting on the possible value of a vaccine for preventing or treating Alzheimer's, she suggested that further study be conducted in sizable, diverse human populations. In addition, Dr. Merrill noted that depending on how long the vaccination procedure may take, people might be wary of a dementia vaccine.

Conclusion: While certain medications can help with specific dementia symptoms, most dementia types are now incurable. Researchers are still looking into the mechanisms by which this illness develops to create better treatments and preventative measures. The development of these vaccines will help both the doctors and the patients to treat and recover in an easy way.