Why are older people more vulnerable to COVID-19?
In almost every country battling with the COVID-19 outbreak, people over the age of 65 are being told to self-quarantine and shut themselves off from other people who might risk infecting them.
Sadly, this means grandparents will not be seeing their children and grandchildren for potentially several months and risk being left emotionally as well as physically alone.
The concern here is not just older people who may get sick; it is the people who will experience a drop in their quality of life in response to the outbreak.
But why is it that these extreme measures need to be put in place, and what is it about older people that makes them so much more vulnerable to catching and developing complications from coronavirus?
The answer lies in their immune systems. As we grow older, we become more likely to develop health problems such as heart disease, diabetes, lung conditions and cancer.
Studies from affected populations in China have clearly shown that having any of these conditions, regardless of age, is a risk factor for developing some of the complications of COVID-19, such as respiratory difficulties and pneumonia. If you throw old age into the mix as well, then you more than double that risk.
When the COVID-19 virus enters the body, we rely on our immune systems to recognise it as a foreign agent and start working to destroy it.
One of the most recognised consequences of ageing is a decline in this immune function. While elderly individuals are by no means defenceless against viruses, they often do not respond efficiently to new or even previously encountered agents.
A major part of a person's immune system is the white blood cells. These are produced in bone marrow as immature cells and travel to different organs, including the spleen, to mature into the army we need to fight off infections.
In older people, the production of white cells in the bone marrow slows down, and the rate of maturation is also much less robust than that of younger people, leaving them with fewer types of certain white blood cells needed to fight off an infection.
When coronavirus enters our upper airways, it is vital that our immune systems identify it as a harmful agent quickly before it has time to spread down into our lungs and cause breathing difficulties.
One of the reasons we might be seeing older people succumbing to the effects of the virus more readily is that their immune system does not recognise and act as quickly as younger people.
By the time it does do this vital job, the virus may already be on its way to the lungs, and much of the damage will have already been done.
But it doesn't stop there. While we need our immune systems to respond aggressively to the virus, we also need it to attack only the infected cells within our body and not healthy cells.
There is evidence that older people's immune systems become less able to distinguish "self" from "non-self" - that is, to identify foreign agents. This may result in something called a "cytokine storm" where the immune system goes into overdrive, not knowing when to shut itself off, thereby attacking healthy cells within the lungs and other parts of the body, making the effects of COVID-19 worse.
In addition, although older people at this stage in their illness may start producing antibodies to the virus, it has been shown that the antibodies become less able to attach to the virus itself and fight it off.
This change may partly explain why pneumonia and influenza are more common among older people and result in death more often.
These changes may also partly explain why vaccines are less effective on older people and thus why it is important for older people to get booster shots.
Lastly, older people can congregate in care homes and nursing homes where highly infectious disease like coronavirus will spread like wildfire.
We all have a duty to protect our older community. Young people may develop milder symptoms, but they are important vectors in transmission and carelessness by them may result in the death of those who are older than us.
Although it may feel like a disservice not to visit elderly relatives, it really is the best thing you can do for them at this time. Regular, daily phone calls and video messaging is far safer and will ensure they do not feel totally isolated.
If you do take food or other essential items to them, they should be left on their doorstep and not taken inside.
It is also important that older people recognise themselves as vulnerable adults during this coronavirus crisis. They often have elderly spouses or parents of their own they may be caring for, and breaks are a vital part of being a carer, making it more important than ever that their relatives and friends phone regularly.
We have a moral duty to keep our distance, wash our hands and, also, to make sure our older people are being taken care of .
Author : Dr Amir Khan
Dr Amir Khan is an NHS doctor and a senior university lecturer in the United Kingdom.