Passive Immunity

                Since before birth, newborns will be developing an immune system. Starting three months before birth (aka the third trimester), mothers begin to send antibodies to their unborn child. This is called passive immunity because the child’s immune system is not actively creating its own antibodies and is just accepting them from the mother through the placenta.

For a few days after birth, the breast milk (known as colostrum) the mother gives the child also contains a great number of antibodies to add to the immune system. This milk has a thick, yellowish appearance due to the high amount of antibodies present.

                The mother’s immune system plays a very important part in what antibodies the child receives. For example, if the mother has had chickenpox, the baby will receive antibodies to protect against chickenpox. If the mother hasn’t had chickenpox, then the child is left unprotected since there are no antibodies to exchange. Also, the child receives antibodies against bacteria and other microorganisms that the mother typically encounters in her environment.

                This immune system is not particularly strong at birth and actually wears away as the child grows older. Some antibodies disappear in a very short amount of time, which is when doctors recommend getting the first shots. The National Health Society (or NHS, which is based in London) states,

“The first immunisation, given when your baby is two months old, includes whooping cough and Hib (haemophilus influenza type b) because immunity to these conditions decreases the fastest. Passive immunity to measles, mumps and rubella usually lasts for about a year, which is why the MMR vaccine is given just after your baby's first birthday.”

                Without the passive immunity, newborns would be much more fragile. Unfortunately, these antibodies do not last forever, which brings us back to the importance of vaccinations. Without a doubt, my sister’s daughters will be receiving vaccines to boost their immunity. So this is the end of baby week! Thank you for reading!

Sources:

http://www.nhs.uk/chq/Pages/939.aspx?CategoryID=54
http://www.gentlebirth.org/vre/newimmun.html