Immunization is one of the best ways to prevent children from becoming ill. Before immunizations became routine, each year thousands of children in the US would become seriously ill with diseases like polio, measles, meningitis, and whooping cough. With the advent of successful immunization programs many of these illnesses are now quite rare.

To provide us with more information on childhood immunizations is Dr. Rebecca Bell. She’s a pediatric critical care physician at the UVM Medical Center and Children’s Hospital, and assistant professor at the Larner College of Medicine.

Listen to the interview at the link below or read the transcript that follows.


What kinds of diseases do these immunizations protect against?

Rebecca Bell: So the childhood immunizations protect against many, many different diseases. They protect against 16 different organisms, but each of the organisms can cause many different diseases. For example, if we talk about the Hib vaccine that’s the Haemophilus Influenzae type B vaccine. It’s a type of bacteria.

That vaccine protects against that organism. That organism can cause many different things, so it can cause meningitis, which is an inflammation of the lining around the brain, and the spinal cord, and that can lead to permanent brain damage, seizure disorders, and death. It was actually the most common cause of meningitis back before we had the Hib vaccine. It can also cause pneumonia, which is an infection of the lungs, and children may end up in the ICU on a ventilator to help them breathe. Those are examples of really serious diseases that are now prevented by the Hib vaccine. Before the vaccine came out, in the US every year we had about 25,000 cases of those serious diseases caused by Hib. Now we have a handful. Something like 10 to 12 cases.

Similarly, the pneumococcal vaccine prevents against many strains of the pneumococcus bacteria, and that bacteria can also cause meningitis. It can also cause pneumonia, and so the vaccines were created to help prevent these really serious illnesses in children, but the added bonus is that it also prevents other less serious diseases that these organisms can cause. One of the most common causes in the past for bad ear infections and sinus infections is pneumococcus, and so we’re actually seeing far fewer cases of bacterial ear infections because of the pneumococcal vaccine.

Then we have other vaccines that prevent against viruses that can cause cancer, so there’s the hepatitis B vaccine. Hepatitis B is an infection that if a child gets that they’re very likely to go on to have chronic liver problems. Maybe need a liver transplant or develop liver cancer, so the hepatitis B vaccine will prevent that. Another example would be the HPV vaccine, which protects against strains of the HPV virus that can cause cervical cancer in women and head and neck cancer in both men and women. These groups of vaccines will prevent not just the acute illness and all the problems that are associated with that, like having to be admitted to the hospital, needing medicine, needing other procedures, but then also will prevent the complications that these individuals might experience down the line, like chronic disease or cancer.

If these diseases are so rare, why do we need to vaccinate against them?

Rebecca Bell: A lot of parents ask that. For instance, a lot of parents will ask about polio. They don’t really see polio anymore. Do we really need the polio vaccine? Polio was a disease that in the middle of last century caused a great amount of illness, and suffering, and disability, and death among people here in the US. Then the vaccine was developed and now we hardly ever see polio in the US.

Polio is a disease that we’re working on trying to eradicate from the Earth. Once it’s totally gone we wouldn’t need to vaccinate anymore, but unfortunately, there are areas of the world where kids just can’t get vaccinated and we see outbreaks of polio. Because it still exists somewhere we all need to be protected against it. In this day and age, every disease, every pathogen is only a plane ride away. That’s one example.

Another example is something like measles. Measles also used to be really common here in the US, and lots and lots of people got measles. Most people did fine with it, but every year we had hundreds of people die just in the US alone from measles. Then we got the measles vaccine. We don’t really see it much in the US anymore. It was actually considered eliminated from the US in the year 2000, and what that means is that we don’t see measles all the time here anymore.

What we see is an outbreak. It’s contained. We don’t see any more measles cases for a while, and then another outbreak. The reason why get outbreaks is we have someone from the US who’s unvaccinated who goes and travels somewhere. They pick it up. They come back often to siblings or a community or school that isn’t vaccinated and that can kind of spread that way, or someone could be visiting the US who has the measles and doesn’t know, so that’s how we have outbreaks here. Most recently in the news there was an outbreak in Minnesota of measles among a Somali-American population where the vaccination rates used to be in the high 90s. They dropped to the 40% or so.

Measles, just like polio can actually also be eradicated?

Rebecca Bell: Humans are the only host. We have a great vaccine. We could actually totally get rid of measles, but we have a long way to go. There are lots of people who aren’t vaccinated and we need to continue this effort, but then there are other organisms that we’ll never be able to get rid of. Tetanus is a good example. That organism that causes tetanus lives in the ground. It exists in the soils and people can get tetanus by being exposed to this organism if they’re not vaccinated.

It doesn’t matter if everyone around you is vaccinated. This is not a disease that gets passed from human to human. It comes from the soil and infects you. We take care of patients sometimes with tetanus and they’re not vaccinated and they get exposed to the organism. That’s an example of something that we always we need to vaccinate against because the organism is always going to exist.

Among children who might not be vaccinated and children who might have more serious disease, what are the risks of the vaccination rate being lower? Can you talk a little more about that?

Rebecca Bell: Yeah. Sure. Often times you’ll hear the term herd immunity. What that refers to is that if people in the community are vaccinated then the likelihood of someone getting the disease who might not be vaccinated is lower. If you’re an unvaccinated person but you’re living among people, everyone you encounter all the time is vaccinated, you’re very well protected. That’s sort of the whole idea behind protecting the vulnerable people in our community.

For instance, again, if we go back to measles, children don’t get the measles vaccine until they’re a year old, so every child under a year is vulnerable to measles. If they come in contact with someone with measles or even they come in contact with that person’s droplets even hours after they’ve been a room, for instance, it’s very contagious, then there’s a 90% chance that they’re going to get the measles. Same with somebody who might be immunocompromised, who might be undergoing chemotherapy, who might be immune suppressed because they have a transplant. All those people are vulnerable to these diseases, and so having everyone around them protected is really important.

What happens and what takes place in the doctor’s office when we get a vaccine?

Rebecca Bell: Sure. The basic idea behind every vaccine is to prompt an immune response so that your immune system can recognize and effectively kill the organism if they’re exposed to it in the future. Scientists will use pieces of inactivated viruses or bacteria, or a piece of inactivated byproduct of the bacteria, or in some cases a weakened virus. What they do is that gets presented to your immune system and then your immune system recognizes and then it creates cells to later recognize it and to fight it off in the future.

It’s really mimicking what happens naturally. If you were to have this disease, say, you were to have measles and get sick from it, your body would mount a response. It would create these cells. It would fight it off. Hopefully, you would be okay and then at the end your immune system can fight it off again in the future. The vaccine works in a similar way, but it’s controlled so that you can’t actually get sick from the vaccine. You get the benefit of being protected from the organism, but you don’t have to get sick from it.

Some people like to say it’s sort of like giving your immune system Cliff notes so that it’s prepared for the test. A lot of people use an army or a military analogy, so your immune system has all sorts of forces and cells to fight off these organisms. The vaccine is sort of like giving intel to the army. You give information to the army. The army can say, “Okay, this is what the enemy looks like. We’re going to train for it. We’re going to be able to recognize it. We’re going to send cells out to actually recognize if this organism ever shows up in the body so we can neutralize it really quickly.” That’s sort of the idea for the vaccine. It’s a great way to let your immune system do its things. It’s just letting the immune system do what it would naturally do, but with the benefit of not actually getting sick from it.

What would you say about the connection or lack of a connection between vaccines and autism?

Rebecca Bell: I would assure parents, and I always assure parents that this is actually a question that’s been studied really extensively. It’s one of our most researched questions in medicine, and so this is something that’s been looked at a lot. It’s been looked at among huge populations of children, so millions of children. Over a million children. Over many continents over a long period of time. We have never been able to find a link between vaccines and autism. However, the myth does persist, as you mentioned, and that has been really difficult.

I mentioned that Somali-American population in Minnesota. That population dropped. It’s MMR, the measles, mumps, and rubella vaccine, way down low to a point where there were just a set up for having an outbreak in their community. That was due to misinformation about the MMR and autism. This is just in recent years. Despite the fact that we have such great evidence and such reassuring evidence that this myth really still persists, and that’s something that as pediatricians and public health experts we’re trying to find ways to get the message out there and in an effective way.

What do you say to parents who are unsure about immunization and on the fence about it?

Rebecca Bell: Well, first, I would really recommend and encourage them to talk to their pediatrician. It’s really important to ask questions. I think things are getting a little polarized to the point where parents may be worried that if they ask questions they’ll be labeled as anti-vaccine, and we don’t want that to happen. We want parents to ask questions. We expect it. We know that parents have questions about that.

What I tell parents is, you’re going to see a lot of scary information online. If you’re watching that YouTube video where someone’s talking about how terrible vaccines are or you’re reading that blog from a website that you’re not really familiar with, just remember that those are folks who … Everyone has a right to say what they want and write what they want, but they’re under no obligation to be truthful and to give you facts. Even on some of those websites you might see a disclaimer that says, “This is not medical advice. Please consult with your doctor.”

That’s really important to remember because pediatricians are required to give you the accurate information and they’re also invested in your child and your family, and know and care for your child. Other really trusted good sources to go to would be, again, the CDC website. is the American Academy of Pediatrics website for parents. Another great source is the Children’s Hospital of Philadelphia’s website called the Vaccine Education Center. That has some great resources for parents and answers all the really common questions that parents have.


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