The current pandemic has revealed that older adults are the most vulnerable amongst all age groups. Scientists have worked extensively to understand why older adults are more susceptible to this virus. The research has revealed that immunosenescence is what makes older people easy targets for the virus. Hence, vaccination solely won’t be effective to protect the older aged people against Covid-19.
The general mechanism of vaccines is to stimulate the immune system to fight against foreign invaders in the body. As aging loses the body’s immune vigor, vaccination fails to be effective. Hence, scientists have planned to improve the immunity of aged individuals with appropriate drugs before administering the vaccine.
There are various reasons for the immune system to act less efficiently among the elderly, some of which are stated below.
- Aging causes a reduction in the number and diversity of naive T cells.
- Aging not only causes a reduction in the number of B cells but also makes them less functional. This limits the production of antibodies, thereby making the body vulnerable to various invading pathogens that cause harm to the body.
- Aging causes inflammageing (chronic and low-grade inflammation) which in turn is caused by an overactive immune response.
Various research laboratories working on the development of an effective vaccine against Covid-19 have reported their results based on the phase trials containing people of all age groups. For example, Moderna in Cambridge, Massachusetts, reported that in their phase I study, comprising people of age 56 and over, showed a similar level of antibody, in both older and younger age groups. Similar results were also reported by the Sinovac, a Chinese biotech company based in Beijing. Their phase I/II study revealed that both the younger and older age group elicited a similar level of antibodies. However, such results were not obtained by Pfizer, an American multinational pharma company, and BioNTech (Germany). Their phase I trial showed that older adults’ response was a lot milder in comparison to younger people.
To improve the immune response of older people, scientists have developed anti-aging drugs. Matt Kaeberlein, a gerontologist at the University of Washington in Seattle says these anti-aging drugs can play a role of a primer before vaccination. Drugs like mTOR inhibitor and rapamycin could be used as anti-aging drugs. Claire Chougnet, an immunologist at Cincinnati Children’s Hospital Medical Center in Ohio, USA, stated that developing medicines to boost immune response is a smarter approach than to develop vaccines specifically for old people as vaccine development is time consuming and a cost-effective process. Scientists believe this technique could have broader applications. It could not only be beneficial for the production of a vaccine for Covid-19 but also be applied for various other diseases including cancer.