Infant Immunizations
Are you preparing to welcome a newborn into your home? Babies bring so much joy into our lives, and so much responsibility! Because babies are vulnerable, and because they are newcomers to our homes, we adults need to take special precautions to protect them. In addition to thinking about safe bedding, breastfeeding and finding the best pediatrician, household members need to think about preventing illness in themselves, so that they don't give those illnesses to the new baby.
You may have heard during the H1N1 pandemic about the importance of getting flu vaccines for infants six months and older, and for the family members of those under six months who could not themselves be immunized. Most pregnant women should be immunized for influenza, and dads, and other household members need to be immunized too.
In addition, it is very important that everyone at home over the age of 10, including mom and dad, get a Tdap booster, if they haven't had one. This version of the tetanus booster came out in 2006. Tetanus boosters (Td) now have pertussis (the "ap" in Tdap) vaccine added to them. Pertussis, or whooping cough, is common among adults and teens. A family member, most often mom or dad, usually infects infants. Whooping cough is often fatal in infants under 6 months old, and almost always requires hospitalization. Even in adults it is not a mild illness—the Chinese name for it means "the 100 day cough". California, Ohio, and Texas are experiencing pertussis outbreaks this year, and six infants in California have recently died from it.
When a woman is pregnant, her body's immune system adapts to tolerate the baby's presence, instead of rejecting it as foreign protein—one of the reasons that she becomes more vulnerable to certain illnesses herself. Her body transfers protective antibodies to infections or immunizations she has had to the baby through the placenta. This is a good reason for women contemplating pregnancy to be updated on immunizations before conceiving. This transferred immunity lasts in the baby's system for about six months after birth. Additional antibody transfer occurs from breastfeeding—not just from the colostrum, but from the milk as well. Breast milk also contains white blood cells to help the baby resist infection. Breastfeeding is the only thing proven to promote immunity in infants besides immunizations, and ideally should be continued past one year of age.
Babies enter this world with no prior experience with germs, as the womb is a sterile environment. The moment they are born, they are exposed to hundreds of types and millions of individual germs, most of which are not infection-causing, but live normally on mom's skin, in her mouth, in her vagina and rectum. These germs will colonize the baby's surfaces as well, and are also part of our protection from harmful germs.
Unfortunately, the world is full of harmful germs as well, some or many of which will be in the baby's home and among his or her family members. Unless mom has transferred immunity to these germs, the baby is liable to become a victim to them. Once the baby is 6-9 months old, especially if he or she is not breastfeeding or is in daycare, infections begin to occur with alarming regularity in most babies. It is not uncommon for infants to have a cold or stomach virus every 2 to 3 weeks in these circumstances, many complicated by ear infections, wheezing, or other complications. Often these infections are transmitted from daycare contacts through the infant to other family members as well.
As bad as colds and stomach infections are, the illnesses targeted by vaccines are much, much worse. Vaccine-preventable diseases include 2 types of meningitis, a bacterial infection of the brain and spinal cord that often kills or causes permanent disabilities. The DPT vaccine prevents pertussis and diphtheria, both of which cause trouble breathing and death by asphyxia, as well as tetanus, which causes full-body muscle spasms for an extended period of time. Polio vaccine prevents paralytic polio; Rotavirus vaccine prevents the most common cause of serious vomiting and diarrhea and dehydration in infants. Hepatitis B, which can kill infants but more often causes chronic infection with liver tumors and liver cirrhosis as a result, will be the first vaccine offered to your newborn, in the hospital. All of these vaccines will be offered to your baby by two months of life. Obviously, these and other vaccine-preventable illnesses are all worse than the minor discomfort and low-grade fever the vaccines may cause.
Why don't babies get shots for every illness at birth?
Vaccines are offered to infants at the youngest age at which they are proven to be both safe and effective. For Hepatitis B vaccine, that means at birth. For most other vaccines, it is at 2 months to 24 months of life. Vaccines are not administered to a child if it isn't safe at that age, and for that reason, influenza vaccine, which causes more fever and local pain in younger infants, isn't offered until 6 months of life. Vaccinations are also not given if they won't work well at that age; the reason MMR vaccine is delayed till age 12 months is that mother's transferred immunity makes the baby less responsive and less likely to develop his or her own immunity. Nevertheless, measles vaccine is offered if the infant is traveling to a country with lots of cases of measles, because it is proven safe down to 6 months.
Why do babies need 3-4 doses of some of the vaccines?
Because some of the illnesses, such as pertussis or meningitis, are much more likely to infect young infants, they need to start immunization early. However, because their immune system isn't fully mature, and younger infants still have some of mom's immunity that may interfere with their own response to the vaccines, they need additional doses as they age to ensure that they develop full protection.
Is it really safe to give so many shots at the same visit?
Babies' immune systems confront hundreds of foreign proteins in their environment every day. This includes every new food they are introduced to as well as the germs, animal dander, dust mites, etc. in their environment. Vaccines have relatively few proteins compared to a new food or other environmental exposures, and much less than the exposure from an infection. Combination vaccines can reduce the pain and provide protection safely. There is no valid reason to spread shots out over a longer period of time—that just increases the risk of catching a serious illness that could have been prevented.
The standard vaccination schedule is well designed and proven to be safe for infants and effective in preventing illness and death. Keep your infant up to date on his or her immunizations!