According to the Centers for Disease Control and Prevention in the USA, reported that the risk of infection with COVID-19 increases with age, especially in older adults, and those who suffered from other immune diseases or continuously taking medications. Some elderlies are immunosenescence due to the decline in an immune system's functionality with age, thus, the COVID-19 vaccine may not be effective for them and it is big trouble. How does the COVID-19 vaccine induce robust immune responses in the elderly?
In general, the number of naive T cells decreases while age increases. This makes the B cells lose their function and less attachment on the antibodies surface lead unable to defend and target the virus for destruction causing it cannot engulf the virus and nor cause inflammation to remove the infected cells. Therefore, it is not easy to develop a suitable COVID-19 for the elderly.
Pawelec et al. indicated that it must have a biomarker in the elderly COVID-19 vaccine. There is an investigation of the Yellow Fever vaccination. (To be continued)...