As a parent, you want to do everything possible to make sure your children are healthy and protected from preventable diseases. The diseases that vaccines prevent can be dangerous, or even deadly—especially in infants and young children. Vaccination is one of the best ways parents can protect their children from diseases that could harm them and the community at large. 

Here to speak with us today about why vaccines matter, is Dr. Sean Palfrey, MD. He is a pediatrician at Boston Medical Center.

Featured Speaker:

Sean Palfrey, MD

Sean Palfrey, MD is a pediatrician at Boston Medical Center. Dr. Palfrey has practiced and taught clinical medicine in Massachusetts for over 35 years, and he spends a good deal of his time advocating for better child health programs and policies. He served as president of the Massachusetts Chapter of the American Academy of Pediatrics and is currently the Director of the Massachusetts Chapter of the American Academy of Pediatrics (MCAAP) Immunization initiative.

Learn more about Sean Palfrey, MD


Melanie Cole (Host): As a parent, you want to do everything possible to make sure your children are healthy and protected from preventable diseases. The diseases that vaccines prevent, can be dangerous or even deadly, especially in infants and young children. Vaccination is one of the best ways parents can protect their children from diseases that could harm them and the community at large. Here to speak with us today about why vaccines matter, is Dr. Sean Palfrey. He is a professor of pediatrics and public health at Boston Medical Center. Welcome to the show Dr. Palfrey. Please explain to the listeners why vaccinating your children is so important.

Dr. Sean Palfrey, MD (Guest): Well, two or three hundred years ago, about a half of all children died before they reached the age of ten. And since that time, for a number of different reasons; probably the two primary ones being clean water, washing your hands and vaccinations; we are down to a tiny, tiny fraction of the infant mortality and the child mortality that we had hundreds of years ago.

Melanie: So, some common misconceptions that exist around vaccines and some of the reasons that parents question them are, are we getting too many at once, the links to various things like autism. Clear up some of these and explain about the safety of vaccines today.

Dr. Palfrey: We know more about the safety of vaccines than we do about almost anything else including all of the foods we eat, the activities that we undertake every day like driving and smoking and drinking sugary beverages. And vaccines are very, very, very much safer than any of those other activities that we all engage in every day. What we have known is that we have tested literally millions perhaps billions of people for the side effects of vaccines. And we know that as with everything else, there are very rare and occasional adverse effects such as pain and fever and allergy, but we basically know who is going to get those. We know how to respond to them and we know that they are very much less dangerous to us, our children, or our grandparents than are the natural diseases that we are preventing with the vaccines.

Melanie: So, when parents ask you about the alternative schedule because they feel that combining vaccines is not a safe thing to do; what do you tell them?

Dr. Palfrey: A couple of things. One is that what we have done is we have tested combining vaccines and not combining vaccines and we find that combining vaccines is actually more effective than not combining them, because the body mobilizes its immune system to respond and will fight off and be much more prepared for future illnesses and exposures, if we give the vaccines together. So, one other thing is that in the old days, 25 years ago, 30-40 years ago, the vaccines themselves were much cruder than they are now and so now for instance, when we talk about the flu vaccine which a number of people feel gives them fevers and flu; we can say to them that the flu vaccine that you get as a shot has no flu in it and cannot produce the flu. That’s true for the same – the other vaccines in many cases that we give, has no live vaccine agent in it, however, there are a few live virus vaccines for instance that have been so weakened that we know that they cannot cause the illness itself. But they can fool the body into thinking that it has been approached by the virus and thus help the body protect itself when it actually is approached by the virus.

Melanie: Dr. Palfrey, clear this up once and for all about the link between vaccines and autism and why this is such a problem that people are believing this link that has been disputed by experts all over the world.

Dr. Palfrey: It has not only been disputed by experts, but by the facts and the facts are that after getting various vaccines that we thought might be associated with it years ago; that in fact, there is absolutely no relationship to the giving of vaccines and the incidence of autism. Part of the problem is that it relates to a very old superstition which is if something happens after something else if you go crazy after there an eclipse of the moon, which is what a lot of people felt happened; that it was caused by the eclipse of the moon. The fact is, that autism was often diagnosed soon after the child got a particular vaccine and the relationship between the vaccine and the autism, simply doesn’t exist when you are looking over millions and millions of patients. And so, we know that the vaccines that were published by Dr. Wakefield some 20 years ago or so, we're actually not at all related to the autism that was diagnosed after it. Now, 20 years’ worth of study later, we know for sure that that is not an associated factor.

Melanie: And what about delaying some vaccines or following an alternative schedule when a parent asks you about that; what do you tell them about the importance of following the schedule as set out by the American Academy of Pediatrics and the CDC?

Dr. Palfrey: Right, well the CDC and the AAP have studied these vaccines and their effectiveness so deeply that what they find is that there are windows of opportunity that we as parents and doctors should be giving the children, our children the vaccines to optimize their effectiveness. And those windows are usually a matter of months. So, if you give the vaccines within that window of opportunity, then they are safe and effective. If you give it outside that window of opportunity, they are totally safe, but they are not nearly as effective and what we want to do is to get vaccines into children particularly babies, but any aged children before they are exposed to the natural illness that is so devastating in many cases. So, you can give a vaccine anywhere within a two-month period and if you as a parent choose to give the child a vaccine at one visit and then come back a month later and give other vaccines at that time; you can certainly do that. It makes for many more visits of you and your child to the doctor, it associates the doctor’s office with getting shots, but if it is still within the windows that the CDC and the AAP have defined; they are perfectly effective. But it is quite clear to us that giving the vaccines all at once, at the same day, that that actually generates a very good immune response without harming the baby in any way and that’s why we recommend we give the vaccines when we do, on the schedule we do.

Melanie: And speaking of windows of opportunity, we learned about newer vaccines like the HPV that must be given during this window of opportunity before a child becomes sexually active or may encounter some kind of sexual activity. Explain just a little bit about what we have learned about the HPV vaccine and why it is so important to be given to children in their tweens.

Dr. Palfrey: Well, first of all, it is one of two vaccines that we have and commonly give or recommend giving that prevent cancer and the first one is hepatitis B vaccine that babies get and that prevents liver cancer. The HPV vaccine the human papillomavirus vaccine prevents cervical cancer in women which is one of the commonest forms of cancer in adult women and head and neck cancer in men and we know that it is extraordinarily effective especially the more recent iteration. We know it is effective in two doses and we know it is more effective if we give it before the child reaches the age of 14 or 15 years of age. So, as you were saying, giving it at 9,10 and 11 years of age, is the ideal time and whatever visit happens in that age range and we like children to come every year, you can now get two doses of HPV vaccine before and almost any child is going to be exposed to the HPV virus, but we also know that almost every sexually active adult is exposed to and infected by HPV and therefore we want to get the vaccine into the children before they are exposed to the virus in a natural way.

Melanie: Why are some vaccines, why do they require more than one dose? And HPV for example, used to be three, not it is two; but some of them like MMR or any of these others do require a second dose. Why is that?

Dr. Palfrey: There are several reasons for that, but the simplest one is that we often need to boost immunity in any case and that is why we give babies several doses of the same vaccine two months apart or three to six months apart in the first couple of years of life because you give the first one, it creates some immunity, you give the second one a couple of months later, it creates more immunity and then you give the third one and it creates immunity that can last for many years. What we have discovered with some of these vaccines is that they are not as strong as the natural illness that we are trying to prevent and therefore, we have to boost them every ten years or whatever it happens to be that science tells us when the child is becoming less strongly immune to the vaccine. So, as we work this through, we will find that we may have to give booster doses of a variety of vaccines as we get along further and or older. And the vaccines themselves, are strong and so you were asking about the HPV vaccine why we only have to give two of them now. The one that we have now is stronger than the one that we used when we first started giving HPV vaccine and the combination of a stronger vaccine and giving it at a slightly earlier age as recommended now at age 9, 10 and 11; provides enough immunity that we only have to give two vaccines instead of three.

Melanie: In summary, Dr. Palfrey, wrap it up for us about why vaccines are so important and that if children are not vaccinated they can spread disease to other children who are too young to be vaccinated and even cover a little bit about the importance of the flu vaccine for this particular reason. Wrap it up for us.

Dr. Palfrey: Well, second only to clean water, probably vaccines are the most important public health effort that we have ever made in human history. They have prevented more deaths and more illnesses than anything else. So, we know now that this is effective. We also know that it is extremely safe if administered in the right way. We know that for instance, people like myself who have been in practice for 40 years, saw children dying left and right when they did not have the vaccines before the vaccines were ever developed and now that the vaccines are in common practice, we can see that everybody is healthier. As you said, it is not just for those people and infants who get the vaccine but by giving one person the vaccine, we are protecting the family and the community around them. So, we are doing a public health benefit by vaccinating every single one of us. That’s the reason why it is so important to get everybody to get the flu vaccine because flu is very contagious and if we can get everybody in a particular community vaccinated, then the flu illness itself, is not going to penetrate that community with the same depth and intensity than it would if you had fewer or no people vaccinated for it. So, we attempt to do something which is to cause herd or community immunity by vaccinating as many people as we can, so that we can keep the virus out of that community by sheer numbers. There is no place for that virus to go, so it will not come into my community if my community is well vaccinated. If your community is not well vaccinated, it can get in through all the corners, it can infect the older people and the very young people and they in turn, not only will be harmed, but it can affect everybody else.

Melanie: Thank you so much Dr. Palfrey. It is such important information to hear about vaccine-preventable diseases and the importance of vaccinating on schedule and if you have questions, be sure to ask your pediatrician because they will give you the facts and the best answers. This is Boston Med Talks with Boston Medical Center. For more information, you can go to That’s This is Melanie Cole. Thanks so much for listening.