COVID-19 had a significant impact on all our lives, but none more so than people with dementia. The reasons why COVID-19 is so devastating for people with dementia are still being investigated, with a recent study shedding more light on the risk of COVID-19 for dementia. *

COVID-19 is caused by the SARS-CoV-2 virus. Being infected with the virus results in people developing flu-like symptoms by developing a fever, a dry cough, fatigue, headache or a sore throat. The vast majority of people experience only these flu-like symptoms when having COVID-19. However, right from the beginning when the COVID-19 pandemic started it became clear that older people were, in particular, more vulnerable to the disease, developing more severe symptoms or even dying from the disease. The reasons why COVID-19 is particularly severe and potentially dangerous for older people are still not entirely clear. Still what has emerged is that the disease is particularly severe for older people who have other age-related health conditions, such as Type II Diabetes or blood pressure hypertension.

Why do make such age-related health conditions us particularly vulnerable for severe COVID-19 symptoms when we are older?

To get a better of this, we need to understand first how the more severe stages of COVID-19 develop. We already know that for the vast majority of people COVID-19 will present as flu-like symptoms but for the more severe cases, there are commonly three stages which people go through after they have flu-like symptoms:

1. The first stage in more severe COVID-19 is that the virus causes fluid to enter the lungs. The increased fluid in the lungs causes people to have ‘respiratory distress’, which means they find it harder to breathe. Most people developing such symptoms are admitted to hospital and are given oxygen to help them breathe. For some people with more severe COVID-19, this is all the treatment they need and after oxygen therapy, they can be discharged from the hospital. However, for a small percentage of people, they develop the symptoms of the next stage of severe COVID-19.
2. The second stage of severe COVID-19 symptoms causes our blood cells to clump together. Such blood clumps make it much harder to get oxygen from the lung to the organs, worsening the outlook for the whole body. For some people, these blood clumps can also block brain blood vessels causing mini-strokes. Understandable the second severe stage of COVID-19 causes much more severe symptoms in people, as they reduce blood oxygen starts to affect several organs and mini-strokes can damage the brain. The second stage is therefore far more serious than the first stage, however, the clumping of the blood cells can be treated to avoid the symptoms to occur. The last stage, however, it the most severe and very difficult to treat.
3. The third stage of COVID-19 symptoms is that the virus causes the body’s own defence mechanism, the immune system, to go into overdrive. Part of the immune system are the cytokines (from Greek ‘cyto’ = cell and ‘kinos’ = movement), which are proteins used to trigger the immune response and inflammation in response to an infection. The SARS-CoV-2 virus in the third stage of COVID-19 triggers the cytokines to become hyperactive, resulting in a so-called cytokine storm. This means that the body’s immune system is becoming hyperactive and does not only attack the virus but also it’s healthy cells. It is very difficult to treat or stop cytokine storms and hence most people at this stage of COVID have a very poor prognosis.

The different stages of severe COVID-19 make clear why older people with existing health conditions are more vulnerable. For one, if we have preexisting cardiovascular problems, the clumping of the blood cells will make those problems much worse. But also other conditions such as Type II diabetes which weaken our immune system will make our defence for SARS-CoV-2 much weaker, making it more likely that we will develop the more severe stages of COVID-19.

What is the relevance for dementia then?

At the moment it is not clear how these factors interact with dementia. However, we know that people with dementia have a more vulnerable immune system. The reason for this is that the immune system commonly fights already dementia as a disease. If on top of that a virus, like SARS-CoV-2, comes along, it will create another ‘hit’ towards the immune system, making it even harder for people with dementia to fight this new virus. This might make people with dementia more vulnerable to COVID-19, as the immune system is quite comprised in dementia generally, particularly in the latter stages of the disease. This explanation would also fit the common finding that most people with dementia do not die of dementia but instead a chest infection or pneumonia. A strong infection, such as COVID-19, might affect therefore the prognosis for people with dementia to cope and survive the disease.

The recent study in the Lancet Psychiatry confirms this assumption. In the study, the authors investigated how people with dementia in a psychiatric ward in a hospital were affected by COVID-19. Their results replicated previous findings, that people with pre-existing health conditions (so-called co-morbidities) are of particular risk to develop the more severe forms of COVID-19, regardless of whether someone has dementia or not. However, a diagnosis of dementia played a significant role in the survival of COVID-19 with a higher proportion of people with dementia dying of COVID-19 than people of a similar age with other pre-existing health conditions.

Where does this leave us in terms of COVID-19 and the risk for people with dementia?

The findings highlight that people with dementia are of particularly high risk to die from COVID-19. We can only speculate at this stage that this might be due to people with dementia have a potentially compromised immune system due to the disease. The compromised immune system would make any other infection, such as COVID-19, have a significant impact on them with a poorer chance of survival of COVID-19.

This is fairly sobering news for people with dementia and their families but it highlights how vital it is to follow government guidelines for COVID-19 and especially shield people with dementia from being inadvertently exposed to COVID-19. Such social isolation will have likely a significant impact on their mental health but given the risks of dying with COVID-19, it might be a price worth paying.

* Prevalence, management, and outcomes of SARS-CoV-2 infections in older people and those with dementia in mental health wards in London, UK: a retrospective observational study. Livingston G, Rostamipour H, Gallagher P, Kalafatis C, Shastri A, Huzzey L, Liu K, Sommerlad A, Marston L. Lancet Psychiatry. 2020 Oct 5:S2215-0366(20)30434-X. doi: 10.1016/S2215-0366(20)30434-X.