Some experts fear vaccines may not even meet the 50% efficacy threshold that the WHO has advised for vaccine candidates qualifying for use.
Immunosenescence—or the immune system losing its vigour in the elderly—is perhaps one of the factors why Covid-19 has affected the old disproportionately in many countries. What makes it worse, though, is the fact that it is likely to undermine vaccine protection among seniors. Some experts fear vaccines may not even meet the 50% efficacy threshold that the WHO has advised for vaccine candidates qualifying for use.
While some vaccines have reported equal efficacy in older as well as younger subjects, some others have shown considerably reduced response amongst seniors. As countries draw up their vaccine roll-out plans—India is targeting, among others, elderly people with co-morbidities for first vaccines that will become available in the country—they have to contend with this problem.
Against such a backdrop, interventions that will pump-prime the immune system among the elderly, as Nature reports, could become quite important. A high-potential intervention could be a class of anti-ageing drugs that inhibit a protein called mTOR that is a key element of cell-growths pathways. A 2018 study involving 264 participants receiving low-dose mTOR inhibitor showed that those received the drug had lower incidence of infections and responded better to the flu vaccine.
At a time when there are uncertainties surrounding the efficacy and duration of protection of a Covid-19 vaccine, the best shot for India and other countries would be to consider supplements that increase the chances of the vulnerable getting due protection.