Immunity in Children

Microscopic pathogens are all around us—they’re impossible to avoid. Whenever we’re exposed, our immune system fights back by analyzing the threat, designing antibodies, and then producing enough of them to disable the infection. It will also remember that design, allowing it to easily produce more antibodies later if a similar threat comes along.

At birth, children’s immunity is like a blank sheet of paper. They’ve had no exposure to pathogens, so they carry no memory of how to fight them. 

Usually, a child’s first exposure to bacteria is in the birth canal. This exposure triggers the initial development of the immune system. Children delivered by C-section do not have the same exposure as those naturally-born, which can impair normal development.

All babies have weak immunity during the first weeks of life. At this time, they are normally protected by the antibodies they receive from the mother’s milk. There are no antibodies in formula milk, so babies who drink formula milk cannot receive this protection.

Doctors need to wait until a baby’s immune system is strong enough before they administer vaccinations, which rely on the body’s ability to design and remember antibodies. With the exception of hepatitis B, bacilleCalmette-Guerin (BCG) and OPV—which are all given at birth—the recommended age to give most vaccines is at two months, or six weeks at the earliest.

When functioning properly, the immune system can identify a variety of threats including viruses, bacteria and parasites. Children whose immune systems do not have the strength to fight are more likely to get both recurrent and life-threatening infections.

For a child, developing a mature immune system is crucial to good health throughout all stages of life. So how can we augment this ability and improve the natural immune system?

The first way is nutrition:

  • Infants of less than one year of age rely on breast milk for their antibodies. We recommend breastfeeding for as long as possible—at least until twelve months of age—and exclusively for at least the first six months.
  • By seven or eight months, we need to provide babies with a variety of foods from different food groups. The protein, fat, carbohydrates and even minerals and vitamins in solid food are very important in improving the health of the immune system.
  • Many parents routinely give children multivitamins and mineral supplements without seeking medical advice. This is not a good practice, because with some vitamins, an overdose is toxic. Oil soluble vitamins such as vitamins A, K and E can be very dangerous, causing seizures, nausea and vomiting.
  • Vitamin D is an exception. Babies normally produce their own vitamin D in response to direct sunlight, but as the exposure to ultraviolet radiation in sunlight is risky, it’s better to supplement the diet with one drop with 400 international units of vitamin D per day.
  • While good nutrition boosts the immune system, overfeeding can lead to diabetes. Obesity and gastro-oesophageal reflux are also potential consequences of overfeeding in infancy.

The second way is sleep quality:

  • Good sleep is very important in nurturing the developing immune system, so a child should have an environment that is conducive to the quality of sleep.
  • A newborn baby should sleep 18 hours per day, and a toddler 12–13 hours per day. A preschooler should sleep 10 hours per day.
  • It’s important not to disturb a sleeping child; which is another reason to avoid bottle feeding infant children, as many parents wake their babies to feed, compromising their developing immune system.

Hygiene is the third way to boost immunity:

  • It is most important to wash hands before preparing meals, or after going to the toilet. The immune system includes the skin and its oil, so washing the hands helps to reduce the spread of pathogens.
  • Very young infants should avoid contact with sick people, and not be exposed to smoking in the home, chemicals (choose organic food where possible) and pollutants in the air.

The last method is vaccination:

  • It’s very important to follow the vaccination schedule. The schedule is carefully planned to take into account the developing immune system. If we vaccinate too early, the baby has insufficient ability to produce antibodies. If too late, then the risk of a child being infected without the protection of immunity becomes greater.
  • By properly adhering to the standard vaccination system, you give your child the best chance of developing a robust and healthy immunity that will serve as a lifelong protection against infection.

*Dr. Nguyễn Hữu Lĩnh’s studies in France and the US gave him a broad experience base in treating a range of paediatric illnesses. He takes particular care in co-operation, communication and education of parents to ensure a better treatment environment for children in medical need.

Dr. Nguyen Huu Linh - Pediatrician, Family Medical Practice Ho Chi Minh City