The importance of sleep in our lives cannot be understated; extensive research over the years has highlighted the relationship between sleep, our physical health and virtually every system of the body.

The immune system is very critical to overall health, it is fundamental to healing wounds, warding of infections and protecting against life threatening diseases/illnesses. There is need to have a strong immune system, especially in the current pandemic.

When you sleep, your immune releases proteins called cytokines, some of which helps you sleep better. Cytokines will increase when you have an infection or inflammation, or when you are under stress. Sleep deprivation may decrease the production of cytokines, antibodies and cells.

RELATIONSHIP BETWEEN SLEEP AND YOUR IMMUNE SYSTEM

Getting sufficient hours of quality sleep improves your defense system; this system features strong innate and adoptive immunity, efficient response to vaccines and less severe allergic reactions. Sleep is an essential part of building up the body’s Immunity and making sure it is operating at full capacity when healthy.

On the other hand, serious sleep problems can interfere with the healthy functioning of the immune system.

According to Dr. Teofilo Lee-Chiong (https://www.nationaljewish.org/doctors-departments/providers/physicians/teofilo-l-lee-chiong-jr), during these uncertain times, while the world is battling an infectious disease, it is essential to optimize sleep to ensure the immune system remains strong, and to support mental well-being. He suggests:

Maintaining a regular bedtime and waking time. Schedule a protected time for sleep, including an anchor period (i.e., same 4-6 hours regardless of schedule). 
Napping to reduce daytime fatigue but not regularly doing to replace a restful night sleep. 
Cutting down on alcoholic beverages, energy drinks and foods containing caffeine, such as dark chocolate, at night.
Limiting the consumption of sugar-sweetened beverages, candies and desserts that can worsen sleep quality. 
Keeping the sleep environment comfortable, dark, quiet, and cool.


FINALLY

According to The National Sleep, the data below reflects the ideal amount of sleep in normal circumstances; however, there are certain cases when people need more sleep, for example, while recovering from illness, jet lag, radical time zone shift, etc.

Newborns (0-3 months): 14-17 hours
Infants (4-11 months): 12-15 hours
Toddlers (1-2 years): 11-14 hours
Preschoolers (3-5 years): 10-13 hours
School-age children (6-13 years): 9-11 hours
Teenagers (14-17 years): 8-10 hours
Younger adults (18-25 years): 7-9 hours
Adults (26-64 years): 7-9 hours
Older adults (65years and above): 7-8 hours


See also:

https://www.wincofoam.com/why-sleep-really-matters-for-your-health/