Q. Since the MMR contains a live version of the measles virus, some people wonder if you could be contagious right after you get a shot.
A. It's an attenuated [weakened] live virus, so we're not really worried about it. You get an infection but it's not enough to make you contagious. It gives you a good immune response, but it doesn't cause a full-blown infection.
Q. If you're an adult who doesn't know your vaccination status, what should you do to ensure that you have immunity?
A. If you were born in 1956 or earlier, then you're considered immune because everybody got measles back then. You don't need anything at all. It's important to let people know that. For other adults, most of them have had a vaccine, but it's a little complicated because there were a few years when the vaccine didn't work very well. (Editor's note: Between 1963, when the measles vaccine was released, and 1967 people received a killed vaccine that wasn’t as effective as the current live-virus vaccine.) So we didn't consider a person vaccinated until 1968.
But if you don't remember if you've been vaccinated, you can just take another dose, that's fine. Some people want to get (a blood test) to see if they have antibodies. You can do that and see if you have antibodies before you get the shot. But the shot is very safe. Even if you've had it before and don't need it, it won't hurt you at all [to get an extra dose].
Q. A second dose of MMR was recommended in 1989 as a severe measles outbreak ultimately infected 55,000 people, including some vaccinated children. More than 120 people died. Was there a problem with the vaccine?
A. No, it's actually a very effective vaccine but to achieve herd immunity, to knock a virus out of the community so it actually can't get into the community at all, you really have to achieve a very high level of protection. So let's say you give a vaccine and 10 percent of kids don't take on that first dose, it may seem like the virus went away for a while but then eventually as more kids come up that aren't immune, eventually you'll have enough kids that can create the potential for an outbreak.
Q. What about pregnant women?
A: That’s a special group that can't be vaccinated for measles, because it’s a live vaccine. Not that we know it would cause a problem -- but just to be cautious. Two vaccines are recommended for pregnant women: flu and Tdap (tetanus, diphtheria, pertussis). They're both killed vaccines with no live components.
Q. What are the chances that a person vaccinated against measles or pertussis (also called whooping cough) can transmit the disease?
A. We don't think that the vaccine creates a "carrier state" in people who have contact with a case. Not at all. We think they provide protection for themselves, their family, their community, for everybody. Each person provides a tiny amount of herd immunity.
Q. Adults often don’t worry about getting vaccinated, because they think of measles, whooping cough and other vaccine-preventable diseases as childhood diseases. But aren’t some infectious diseases more dangerous for adults?
A. You're probably thinking of chicken pox and that's true. There were worries when the childhood chicken pox vaccine came out that it would push the age of chicken pox to older children and adults, where the disease is much more virulent, but we actually recently published and showed that that didn't happen. It was such a good vaccine that it took away chicken pox for everybody, it had a big herd effect.
But yes, diseases in childhood can be worse in adults. Measles is not an easy event for anybody. A full-blown case of measles is a rough illness for anyone.
Q. Are there any vaccines that seniors should make sure they get?
A. They don't have to worry about measles at all. With the pertussis, they just have to be aware that they can get it, but pertussis is much more of a problem in infants, teens and family members. When it comes to the elderly, we're really talking about flu and pneumococcal and Zostavax (for shingles). The older they are the more likely they should get the high-dose flu shot. And the shingles vaccine is recommended at age 60 and above.
Q. A recent Pew study found that over 40 percent of young adults, ages 18 to 29, think childhood vaccinations shouldn’t be required but should be up to parents. And a 2013 Harris Poll found that 61 percent of people think drug companies minimize vaccine risk. As head of the Vaccine Study Center you’re constantly reevaluating the safety of vaccines. How safe are vaccines compared to widely prescribed preventive drugs like statins? And what are you looking for in your studies?
A. What I see in what I read and hear from people is that there's a total lack of trust with regard to vaccines. They feel that there's some sort of hidden information that someone's covering up that they're really not safe. But I've been looking at this for years and we work with a lot of people who are dedicated to the safety of vaccines. There's no hidden agenda here. We care about these kids and about the people we give vaccines to. We want to ensure that the vaccine supply is extremely safe and stays safe. That's why there's ongoing surveillance. Even though we don't see signals of risk we keep looking for it.
The problem is that when you say you're looking for something people think it's there, so the discussion can be very difficult. When I tell someone we didn't see something in a vaccine, if they're not educated on it, they go, "What? You thought it was there?" It's a difficult conversation, and I'm not sure there's a simple answer to that when there's such distrust.
But beyond mistrust, there's also a lot of misinformation out there from people who have an extremely loud voice, on the internet, and are giving information that is neither true nor appropriate. I've actually had patients tell me that they thought their search on the internet was worth more than their visit with me.
