“[When] we already have a vaccine against Covid-19, world leaders will have a choice about how to deliver it to the population. The most vulnerable people, along with the nurses, doctors and care workers who look after them, are likely to be protected first. If only it were that straightforward. The most vulnerable age group, the elderly, are particularly tricky to vaccinate.
“To understand why older people are harder to vaccinate, we have to look at the differences in their immune system. Many infectious diseases are more severe in older adults than younger adults. Older people have more risk factors – a lifetime of exposure to carcinogens or other infectious diseases will increase the risk of future disease from new infections. But they also undergo something called immunosenescence – ageing of the immune system.
“Just like many other parts of the body, our immune system shows signs of our ageing. Some of the immune cells lose their function. The immune system is a very complex network of cell types that interact with each other. If something, somewhere within the system is not working, it interrupts the delicate balance of the immune response. … The issue for vaccinologists is that the delicate balance between all of these cells in elderly people becomes disrupted.”
To read the rest of this article (written in October 2020), including a discussion of treatments, click here. But there are encouraging early results that suggest the Covid-19 vaccines under development not only have high efficacy, but also work well for older people, who may even tolerate the shots better than young people and with fewer side effects (read about that here).