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This is Lindsay Smith Rogers.

Today, as part of our ongoing series on vaccines, a conversation with Dr. Bill Moss about the different

types of vaccines, the childhood vaccination schedule, and the concept of herd immunity. Let's

listen. Dr. Bill Moss, welcome back to Public Health on Call. How are you? Good. Good to see you,

Lindsay. You too. So today we're going to talk about the different types of vaccines.

What are the different types of vaccines? An easy way to think about vaccines is to put them in like a couple of buckets.

And so one bucket are what we call attenuated vaccines, meaning that we take the pathogen that causes the disease and we weaken that virus

so that when it's given to a person, it will induce an immune response, a protective immune

response against that virus, but it won't cause severe disease. For example, measles vaccine, rebella vaccine, mumps vaccine,

those are packaged together, the varicella vaccine. All of those are attenuated viral vaccines.

The old way of weakening these viruses was to grow them or passage them, as we say, in non-human cells.

They adapt to those cells so that when they're put back in us, they will induce a strong

immune response that will be protective, but they don't cause severe disease.

Sometimes they can cause very mild illness, so sometimes children, for example, get a measles vaccine, may get a fever, they may get slight rash, but they will not get severe disease. And the whole point behind vaccination is to show our immune system what this pathogen looks like so that our body will recognize it,

should we be exposed to it, and we can initiate a much faster and stronger fight against

that pathogen than we would otherwise if we were completely susceptible. So then the other big

bucket are these non-attenuated

vaccines, and that's where many of our vaccines are. They can be inactivated where you, for example,

...