Nikhil Prasad Fact checked by:Thailand Medical News Team Jan 30, 2026 1 hour, 43 minutes ago
Medical News: A growing body of scientific evidence is raising fresh concerns that the loss of smell experienced by many COVID-19 survivors may be more than a temporary nuisance and could be an early warning sign of future cognitive decline and Alzheimer’s disease.
Persistent loss of smell after COVID-19 may be an early warning sign of long-term brain and memory problems
Researchers from Fondazione Policlinico Universitario Agostino Gemelli IRCCS in Rome, Ospedale Isola Tiberina Gemelli Isola in Rome, the European Brain Research Institute EBRI in Rome, and the Institute of Translational Pharmacology of the Italian National Research Council have conducted an extensive review examining how long-lasting smell impairment after SARS-CoV-2 infection may affect the brain.
Why Smell Loss Matters More Than People Realize
Loss of smell, medically known as anosmia, affects a large proportion of people with long COVID. While many regain their sense of smell within weeks, a significant number experience persistent or even permanent impairment. Scientists emphasize that the sense of smell is directly connected to brain regions responsible for memory, emotions, and learning, including the hippocampus and limbic system. Damage along these pathways can therefore have far-reaching consequences beyond the nose.
How the Virus Triggers Brain Changes
The study explains that SARS-CoV-2 does not usually infect smell-sensing neurons directly. Instead, it damages supporting cells in the nasal lining and triggers chronic inflammation. This prolonged immune response disrupts normal regeneration of the olfactory system and may lead to shrinkage of the olfactory bulbs, the brain’s first relay station for smell. Over time, these changes can ripple into deeper brain structures involved in thinking and memory.
Links to Cognitive Decline and Alzheimer’s Disease
Multiple clinical studies reviewed by the researchers show that people with persistent smell loss after COVID-19 often perform worse on memory and cognitive tests. Brain scans from long COVID patients have revealed thinning of brain regions associated with memory and decision-making. Importantly, smell impairment is already known to be one of the earliest signs of Alzheimer’s disease, sometimes appearing years before noticeable memory loss.
This
Medical News report highlights that inflammation, oxidative stress, and abnormal protein buildup triggered by SARS-CoV-2 closely resemble processes seen in Alzheimer’s disease. These shared mechanisms raise the possibility that COVID-19 may accelerate underlying neurodegenerative changes in vulnerable individuals, particularly older adults.
Treatment and Prevention Strategies
The researchers stress the importance of early intervention. Olfactory training, which involves repeated exposure to specific scents, along with anti-inflammatory and neuroprotective treatments, may help restore smell function and potentially reduce long-term brain
risks. Monitoring smell loss could also become a simple and cost-effective way to identify people who may need closer neurological follow-up.
Conclusions and Public Health Implications
The findings strongly suggest that persistent smell loss after COVID-19 should not be ignored or dismissed as harmless. Instead, it may serve as an early biological signal of brain vulnerability and future cognitive decline. Long-term studies are still needed, but current evidence supports routine assessment of olfactory function as part of post-COVID care, especially for older adults and those with lingering symptoms.
The study findings were published in the peer reviewed journal: Cells
https://www.mdpi.com/2073-4409/15/2/176
For the latest on Long COVID, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/articles/long-covid
https://www.thailandmedical.news/articles/coronavirus
Share
Tweet
Share
