There are now more than 95 million confirmed cases of Covid-19 worldwide. The disease has reached 193 countries, with the US being the most affected. According to the US Centers for Disease Control and Prevention (CDC), the majority of confirmed cases are seen in adults ages 18–64 years. While most individuals survive the infection, adverse cognitive outcomes may be long-term and result in lower quality of life and disability, particularly among severe cases. So far, some of the most concerning lasting effects of Covid-19 are continued loss of sense of smell or taste, memory or concentration problems, and other cognitive complications, because they indicate probable brain damage and increased risk of dementia such as Alzheimer’s disease.
Currently, the frequency at which Covid-19 patients suffer from seizures, psychosis, and memory-related problems is unknown. Some studies have reported that as many as 84% of patients with severe Covid-19 experience mental confusion and rapid mood changes after they recover. Even if the true frequency of lasting brain damage is lower, the number of people with lasting cognitive problems will be substantial because so much of the population has been infected.
The loss of smell and taste in Covid-19 patients emerged as one of the first signs that SARS-CoV-2, the virus that causes Covid-19, is affecting the brain. A team of researchers looking at the brains of deceased Covid-19 patients found that the virus can remain in the brain after death. Other observations from these autopsies revealed small blood vessels in different areas of the brain were leaking as if patients had suffered mini-strokes. A team of researchers has reported in the January issue of Alzheimer’s & Dementia that the brain inflammation and mini-strokes observed in Covid-19 patients may place them at increased risk of developing Alzheimer’s disease and other dementias.
Alzheimer’s disease is a growing global health crisis, as the world’s population is ageing. GlobalData’s epidemiological forecast of Alzheimer’s disease estimates that total prevalent cases will increase from approximately 34 million cases in 2019 to over 44 million by 2028 in the eight major markets (8MM*). Growing evidence of cognitive impairment as a result of Covid-19 could mean an even larger number of people developing Alzheimer’s disease in the next ten years. Given that most cases of Covid-19 occur in the population ages 18–64 years and most patients of Alzheimer’s disease are 65 years and older, continued monitoring will be critical to understanding the relationship between Covid-19 and Alzheimer’s disease. Research related to brain damage and dementia as a result of Covid-19 will help public health officials plan and allocate resources to better care for a population suffering from disability and diminished quality of life.