Understanding Your Newborn’s Immune System

Close Up Of Father Holding Newborn Baby Son In Nursery

Flu season is in full swing, and everyone’s antibodies are working overtime to protect them from nasty bugs. Everyone’s except for the infants of the world, that is.

As a new parent, you might feel too overwhelmed with diaper changes and breastfeeding to think about your baby’s immune system, but now’s the perfect time to understand how it works. Take a moment to read through these facts to learn how you can protect your little one from a whole host of viruses and bacteria:

How your baby’s immune system develops

Immune system development is a lifelong process. Even now, your white blood cells may be producing antibodies to stave off new viruses and bacteria. But babies don’t have years of such exposure; their immune systems are brand new and therefore not as strong as their parents’. The Australian Department of Health provided a brief overview of the process:

Before birth

Developing immunity is a process that begins before babies are even born. During the last three months of pregnancy, mom passes some of her antibodies through the placenta, giving her child a bit of protection. This immunity is completely dependent on mom’s own antibodies, however, and it tends to wear off during the first few weeks after the baby is born.

At birth

During the birthing process, the baby is exposed to a drastically different environment. Her new surroundings are full of love but full of pathogens, too. Therefore, her immune system needs to develop quickly to keep her from getting sick. Luckily, mom naturally passes some of the bacteria from her vagina to her infant and, in doing so, helps her child build a colony of organisms in the gut that support immunity.

As baby grows

Mom passes more antibodies to her child via her breast milk. As the child grows, she begins to develop her own immunity each time she is exposed to a pathogen – a virus, bacterium, parasite or other foreign object that could make her sick.

A mother kissing her baby as the child sleeps.Your baby’s immune system slowly grows each time she’s exposed to new bacteria.

Building your baby’s immune system

According to What to Expect, most healthy infants suffer eight to 10 viral infections by age two. These are perfectly normal; in fact, the process of getting sick strengthens a child’s immune system even more. As the pathogen enters the body, baby’s white blood cells start producing antibodies that not only beat the current infection but stave off any more in the future.

That said, your little one may need a bit of assistance getting her immune system up to snuff. Here are some things you can do to help:

Breastfeed if you can

Your milk contains proteins, antibodies, probiotics, fats and sugars necessary for your little one’s health. These compounds support immune system development and overall growth. Plus, as you encounter pathogens and develop your own antibodies to them, your baby gets some additional immunity when she feeds.

If you are unwilling or unable to breastfeed, don’t worry. Your baby can still get vital nutrients from formula, though you may need to check with her pediatrician to make sure her immune system develops properly.


Vaccination is the most effective way to protect your baby against serious diseases like mumps and measles. Vaccines cause the immune system to respond as it would to a virus or bacteria – by producing the necessary antibodies – but without your baby getting sick.

These days, many moms are afraid to vaccinate their children out of fear that vaccines cause autism. While there are some risks to vaccinations, including swelling and possible allergic reactions, learning disabilities aren’t one of them. As the Centers for Disease Control and Prevention explained, there are numerous studies that prove there is no link between vaccinations and autism.

A baby visiting a doctor.The idea that vaccines cause autism is a complete myth.

Focus on a healthy diet

Finally, good eating habits provide the foundation for strong immune system development. As an infant, your little one usually gets all the nutrients needed from milk or formula, so supplements aren’t necessary. That said, you should still use antibiotics and probiotics if your doctor prescribes them.

As your child starts to eat solid foods, include a variety of fruits, vegetables, meats, starches and proteins to keep the immune system running properly.

When your baby has a cold

Unless you live in a bubble, your little one is bound to come down with a cold sooner or later. Also known as upper respiratory infections, colds are caused by viruses that are transmitted through any sort of contact.

Colds aren’t inherently bad; they’re certainly uncomfortable and annoying, but they help build your child’s immune system, after all. Plus, most babies’ colds are mild and last just over a week. You shouldn’t need to call a physician unless:

  • Baby is under three months when she gets her first cold.
  • She’s acting exceptionally uncharacteristic or lethargic.
  • She refuses to eat or drink.
  • Her breathing increases rapidly.
  • She has swollen glands in her neck.
  • She keeps pulling on her ear.
  • Her symptoms last longer than 10 days.
  • She has a low fever lasting longer than 4 days or a fever reaching over 102 degrees.

Otherwise, just boost her fluids, use a humidifier to reduce congestion, moisturize her skin and suck mucus from her nostrils with a suction bulb if necessary.