The World Health Organisation (WHO) has said up to 45 per cent of dementia cases could be prevented by addressing modifiable risk factors, as it unveiled updated global guidelines to help countries reduce the growing burden of the condition.

The UN health agency released the updated recommendations on Wednesday, saying the guidance provides countries with evidence-based measures to prevent or delay cognitive decline and dementia across the life course.

According to the WHO, more than 57 million people worldwide are living with dementia, while nearly 10 million new cases are diagnosed each year. Alzheimer’s disease remains the most common form of dementia, accounting for an estimated 60 to 70 per cent of all cases.

Although there is no cure for dementia, the organisation said a significant proportion of cases are linked to risk factors that can be modified. These include tobacco use, harmful alcohol consumption, physical inactivity, air pollution, social isolation and non-communicable diseases such as hypertension, diabetes and high cholesterol.

Speaking on the updated guidelines, the WHO Director-General, Tedros Ghebreyesus, said advances in research had improved understanding of the factors driving dementia risk, enabling countries to take practical steps to protect brain health.

“We know more today than ever before about what drives dementia risk, and these guidelines translate that knowledge into action,” he said.

Mr Ghebreyesus added that countries now have clear, evidence-based recommendations that they can implement immediately to protect people’s cognitive health.

Updated recommendations

WHO said the revised guidelines reflect significant scientific advances since it first issued recommendations on dementia risk reduction in 2019.

According to the organisation, the updated guidance brings together evidence-based recommendations on reducing unhealthy behaviours, managing medical conditions and limiting exposure to environmental factors associated with cognitive decline.

It is recommended that adults with normal cognitive function or mild cognitive impairment engage in cognitive training, cognitive stimulation and regular social activities to help lower their risk of dementia.

The agency also advised increasing physical activity, quitting tobacco use, reducing alcohol consumption and adopting a healthy diet.

The updated guidance also includes reducing exposure to air pollution as a recommended strategy for lowering dementia risk.

WHO further said managing cardiometabolic conditions such as hypertension, diabetes and high cholesterol could help reduce the risk of dementia. Hearing aids may also be offered as part of risk reduction strategies.

READ ALSO: WHO, UNICEF warn funding gap could reverse immunisation gains in poorer countries

However, it advised against using vitamin B and E supplements, omega-3 polyunsaturated fatty acids and multivitamins or mineral supplements to prevent dementia in people without diagnosed deficiencies, citing insufficient evidence that the products provide benefits that outweigh potential harms.

WHO said the new guidelines incorporate the latest evidence and innovations in dementia prevention and present an opportunity for countries to strengthen the integration of non-communicable disease, mental health and brain health services.

Economic burden

WHO described dementia as a condition caused by diseases affecting the brain, leading to a gradual decline in memory, thinking and the ability to carry out everyday activities.

Beyond its health impact, the organisation said dementia affects people’s independence, dignity and safety while placing substantial emotional, physical and financial burdens on families and caregivers.

It estimated that dementia costs the global economy about $1.3 trillion annually, with around half of the amount attributed to unpaid care provided by family members and friends.

According to the WHO, understanding dementia risk factors and taking preventive action can improve health outcomes and quality of life, enabling more people to live longer, healthier and more independent lives.

The warning is contained in the latest WHO and UNICEF Estimates of National Immunisation Coverage (WUENIC), analysed by Gavi, the Vaccine Alliance.

According to the report, lower-income countries immunised a record 73 million children with Gavi-supported vaccines in 2025, the highest number ever recorded.

It said three-fourths of all countries maintained or improved coverage with the third dose of the diphtheria, tetanus and pertussis (DTP3) vaccine in 2025, the highest proportion in more than two decades.

It added that two-thirds of countries have a DTP3 coverage rate of 80 per cent or higher.

Average coverage across Gavi-supported vaccines, referred to as the “breadth of protection”, reached 65 per cent in 2025, matching the global average for the first time.

According to the report, this represents a 16-percentage-point increase since 2019, driven largely by the introduction and expansion of new vaccines.

Progress in fragile settings

The report also highlighted improvements in countries affected by fragility and conflict.

Average DTP3 coverage across the 12 countries classified as fragile or conflict-affected increased by five percentage points to 66 per cent in 2025.

Sudan recorded the world’s largest improvement, with DTP3 coverage rising by 32 percentage points.

Despite the progress, the report noted that these countries have yet to recover to pre-pandemic immunisation levels.

It added that one-quarter of all zero-dose children in lower-income countries live in fragile and conflict-affected settings.

HPV and malaria vaccines

The report highlighted progress in efforts to prevent cervical cancer and malaria through vaccination.

According to the findings, lower income countries have now protected 95 million girls with the human papillomavirus (HPV) vaccine, including 79 million in the past three years alone. This exceeded Gavi’s target of protecting 86 million girls by the end of 2025.

The report said HPV vaccine coverage now stands at 29 per cent, close to the global average of 31 per cent.

It also noted that malaria vaccines are now being delivered through routine immunisation programmes in 25 African countries, representing more than 70 per cent of the world’s malaria burden.

Although WUENIC does not yet include malaria vaccine data, the report said countries are already reporting reductions in severe malaria cases, deaths and hospitalisations.

It cited Ghana, where under-five malaria deaths fell by 86 per cent between 2019 and 2024, and Burkina Faso, which reported a 32 per cent decline in malaria cases between 2024 and 2025 following nationwide expansion of the malaria vaccine programme.

Measles immunity gaps

Despite the gains, the report warned that immunity gaps for measles remain a significant concern.

Coverage with the first dose of the measles-containing vaccine remained at 80 per cent in lower income countries, while coverage with the second dose increased to 72 per cent in 2025.

However, about 15.6 million children in Gavi-supported countries still missed their first dose of the measles vaccine.

The report warned that the immunity gaps remain a significant concern because of the high transmissibility of the virus and the risk of serious outbreaks.

Funding concerns

Despite the progress recorded in 2025, Gavi warned that sustaining the gains will require continued investment.

The report noted that 2025 was the last fully funded year of Gavi’s current strategic period.

However, it stated that Gavi’s next strategic period, covering 2026 to 2030, is not yet fully funded, putting progress at risk.

According to the report, reduced financing could affect investments in key areas, including malaria vaccine programmes, the introduction of hexavalent and multivalent meningitis vaccines, preventive vaccination campaigns and global vaccine stockpiles.

The report also identified fiscal pressures, geopolitical instability, disease outbreaks, rising birth cohorts and vaccine hesitancy as challenges that are making progress more difficult.

Although the number of zero-dose children declined in 2025, about 9.5 million children in lower income countries still had not received a single vaccine dose.

The report stressed that reaching these children, many of whom live in underserved communities, remains critical to saving lives, promoting equity and strengthening global health security.

Sustained investment

The Chief Executive Officer of Gavi, Sania Nishtar, said the record level of immunisation demonstrates what can be achieved when governments and partners work towards a common goal.

Ms Nishtar said sustaining the progress would require continued commitment as countries face funding constraints, geopolitical uncertainty and increasing disease outbreaks. She added that greater efforts would also be needed to reach children who still do not have access to immunisation.

“The historic levels of immunisation that we are seeing across lower income countries shows what can be achieved when all stakeholders work together towards a shared objective”, she said.

Ms Nishtar noted that as Gavi heads into a new five-year period, its greatest challenge will be maintaining the momentum in the face of funding constraints, geopolitical uncertainty and increasing outbreaks, while working harder to reach children who still do not have access to immunisation.

She called on countries to increase domestic financing for immunisation and urged donors to support Gavi’s 2026–2030 strategic period.