With measles on the rise, two-dose vaccine strategy is 'more important than ever'

• First dose has 95% efficacy rate, but ‘we need to do better’ with virus being so contagious
• ‘It wouldn’t take much for us to have big-time national measles cases,’ expert says

CHICAGO --- Northwestern University pediatric infectious disease professor Dr. Ravi Jhaveri said vaccines are like umbrellas. While they won’t always keep you from getting wet in a terrible storm with sideways rain, they will prevent you from getting soaked.

The first dose gives a person 95% protection from measles, but the virus “is so proficient at finding the vulnerable person, we need to do better than 95%,” said Jhaveri, chief of infectious diseases in the department of pediatrics at Northwestern University Feinberg School of Medicine and head of the infectious diseases division at Ann & Robert H. Lurie Children’s Hospital of Chicago.

Jhaveri is available for interviews with the media. Contact Kristin Samuelson to schedule an interview.

“I think in Texas, it’s a significant rainstorm that’s not sideways yet, but for many of us, we can see storm clouds on the horizon,” Jhaveri said. “And if we believe the misinformation and the flat-out lies about vaccines, I think we’re in for a really bad storm. It wouldn’t take much for us to have big-time national measles cases.”

At the same time, Jhaveri said more than 90% of parents in the U.S. get their children vaccinated every year, which will help if measles cases spike across the country.

“We spend a lot of time talking about people who aren’t getting vaccinated, but a lot of parents vote with their feet and get their kids vaccinated every year, and I want to commend them,” Jhaveri said. “The vocal minority that wants to have their day — and they are having it right now — but let’s not forget the vast majority of people who are vaccinating.” 

The story behind the measles vaccination's two doses

In the decades between when the measles vaccine was first introduced (1963) until the mid-80s, doctors only offered one dose, and cases went down, Jhaveri said. Then the U.S. began to see large national outbreaks with tens of thousands of cases.

“What we eventually figured out was while one dose of vaccine covers most (95%), 5% of people or so may not develop a protective response,” Jhaveri said. “So, we started vaccinating all kids and teens with a second dose, and then got down to kids age 11 with a second dose.”

But since many children didn’t regularly attend 11-year-old wellness checkups, public health officials moved the second booster shot to age four, which is where it now lives, he said.

“This is much more convenient for parents. They expect their kids to be getting boosters, and we can better track vaccinations upon entering school,” Jhaveri said.

A Q&A with Dr. Jhaveri:

What if a child has only had one dose and is in an area where cases are spiking?

Jhaveri: In settings of large outbreaks, there are stipulations in which you can prioritize a second dose before age 4. In certain circumstances, where kids who are younger than 1 year old, you can also give the vaccine earlier.

The reason we don’t vaccinate in the first year is we worry that antibodies from mom might blunt the response to the vaccine. Getting the vaccine earlier than 1 year old will still provide protection, but it doesn’t count toward their two doses.

If someone who was vaccinated with two doses is exposed to an outbreak, are they protected?

 Jhaveri: If someone who is middle-aged and had their boosters many years ago has a prolonged and intense exposure, there’s a chance they could get measles, but I can confidently say it would still be a much less severe case than if they didn’t have any vaccine at all.

With rising concerns about vaccine hesitancy, do you believe other vaccine-preventable viruses could resurface and lead to outbreaks in the U.S.?

Jhaveri: Chicken pox. The vaccine by itself is initially protective and, similar to the measles, started with one dose and then later included a booster. Now we also boost older people with a shingles vaccine to protect them. When the chickenpox virus was still circulating, that exposure was periodically boosting peoples’ immunity. Since we don’t have a lot of chickenpox virus circulating now, you could still have some sustained transmission of chickenpox in a community where the vaccination rate fell way off.

People now remember chickenpox as a mild nuisance, but I think people forget that thousands of kids still got admitted to the hospital and we still had deaths because of complications or bad effects from the virus. The national vaccination of chickenpox has been really effective.

Do we need to be concerned about polio re-emerging? 

Jhaveri: So many people worldwide have been vaccinated, so it would really take a lot for us to see it come back. Right now, there are only two countries worldwide with polio circulating (Afghanistan and Pakistan). Polio is primarily a fecal-oral virus, meaning you’d have to ingest the polio virus in food or water contaminated with the feces of an infected person. It doesn’t transmit nearly as easily the way measles does (through very small aerosols that move through the air).