Vaccines and breastfeeding

I occasionally meet parents who have decided to delay vaccinating their newborn.

Such parents have usually been alarmed by false claims about the risks of vaccines to children, which I have discussed earlier.

Another common worry is that children are “too small” for such vaccines. This simply isn’t true. Vaccines are timed for when a child’s immune systems will respond to them. This is why, for example, polio vaccines are given beginning at age 2 months, while measles waits for 1 year of age—a two-month-old won’t respond properly to a measles vaccine, but will to polio. (Getting such vaccines too soon wouldn’t be dangerous, but it wouldn’t generate an immune response, so there’s no point.)

Parents of unvaccinated children sometimes comfort themselves with the thought that since they are breastfeeding, this provides adequate protection. After all, there are antibodies against disease in breast milk, right?

Breastfeeding is certainly the ideal choice for the vast majority of newborns and their parents. (There are a few diseases or conditions for which you shouldn’t breast feed, and a few drugs that a mother might have to take that would be dangerous to an infant.)

It is also true that antibodies from the mother are passed in breast milk to the baby. But, parents often don’t know what kind of antibodies, and what kind of protection they provide.

And, that’s the rub, as they say.

The Children’s Hospital of Philadelphia has a Vaccine Education Center. Their statement is important:

Sometimes parents wonder whether they can forego immunizations for their baby because the baby is being breastfed; however, this is not the safest decision because antibodies in human breast milk bathe the intestinal surface but are not absorbed. Therefore, breast milk antibodies never enter the lymphatics or circulation where they would be needed to protect against diseases for which infection in the blood (circulation) is an important part of how viruses and bacteria cause disease. Examples of these types of diseases include diphtheria, tetanus, pertussis, measles, mumps, rubella, varicella (chickenpox), pneumococcus, Haemophilus influenzae type b, polio, hepatitis A and hepatitis B.

Antibodies in breast milk enter the baby’s gut. These antibodies are useful, but their only function is to prevent the baby’s gut from absorbing dangerous infections. So, breast milk antibodies are a great way to help prevent things like diarrheal illnesses. That’s no small thing—in the third world, diarrheal illness still kill millions of children every year. (Even in the US, hundreds still die every year from diarrhea.)

So, before modern sanitation and germ theory, breast milk antibodies could mean the difference between a child living and dying, and still does in the third world. (This is one reason why efforts of baby formula companies to convince third world mothers not to breast feed are so pernicious.)

But, breast milk antibodies do not enter the baby’s blood stream or lymphatic system. They stay in the gut. So, breast milk antibodies are completely powerless to fight any infection that enters a baby by any other route—for example: by the lungs, by a scratch on the skin, and so forth.

So, antibodies in breast milk might protect your baby from stomach flu—but, they won’t protect him or her from some of the worst diseases known, including:

  • tetanus (lock jaw)
  • polio
  • hepatitis A and B
  • pertussis (whooping cough)
  • measles
  • mumps
  • rubella (German measles)
  • diphtheria
  • pneumococcus (causes severe pneumonia).
  • H. influenza, type b (causes potential fatal airway compromise)

It is a sad irony that parents worry that their baby’s immune system “can’t handle” vaccinations. It can, easily.

But, their immune systems can’t handle all the above diseases very well at all—newborns are at greatest risk of death or life-long problems from these diseases in the event of an outbreak. This is because of a less well-developed immune system, and the fact that they are smaller.

A baby’s best lines of defense are:

  1. vaccination for themselves; and
  2. herd immunity from a well-vaccinated population for those diseases for which they are too young to mount a proper response.

Once again, your choices don’t just affect you—they affect my kids too. We all need that herd immunity.

Here’s hoping people will use science, and not fear, in making these decisions.

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