Shingles isn't usually considered a kids' disease, but children can get this painful condition. Fortunately, the chickenpox vaccine can also protect them against it, a new study finds.
"The virus that causes chickenpox also causes shingles. It's pretty uncommon in kids, but we wanted to see what would happen to the rates of shingles among children over time as more kids received the vaccine," said study lead author Sheila Weinmann. She's a senior investigator and epidemiologist at Kaiser Permanente Northwest in Portland, Oregon.
Large overall drop
What the researchers found was that kids who were vaccinated against chickenpox had a 78% lower risk of developing shingles. And the rate of shingles dropped in the entire group – vaccinated and unvaccinated – by 72% between 2003 and 2014.
Weinmann said the overall drop was large because so much less of the virus was circulating in the general population.
The study was published online in Pediatrics.
Dr Anne Gershon from Columbia University wrote a companion editorial that argued all children should get the vaccine for the dual protection it offers.
"The vaccine is not only highly protective against chickenpox, but it protects against shingles as well," she said. "Now we have to find out how long the protection will last."
Not severe in children
The chickenpox vaccine is also known as the varicella vaccine because varicella zoster is the virus that causes the disease. The vaccine was introduced to the United States in 1996, when one dose was recommended for 12- to 18-month-olds to protect them against chickenpox, according to background information in the study.
Since 2007, a booster at four and six years of age also has been recommended.
Dr David Fagan, vice chair of paediatrics at Cohen Children's Medical Center in New Hyde Park, New York, said shingles isn't usually severe in children, unless their immune system is compromised. He wasn't involved in the current study, but is familiar with the findings.
Shingles (herpes zoster) usually develops in much older people who had chickenpox as kids. After a chickenpox infection, the virus lays dormant until something triggers it to reactivate. It's much more common in people after age 60, Gershon said. "As you get older, the immune system gets tired," she explained.
To see how varicella vaccine would affect the rate of shingles in kids, the researchers collected health information on 6.4 million children, ages one to 17. More than 14 300 developed shingles during the 12-year study period.
Effect on seniors unknown
Overall, about half had received the chickenpox vaccine. In 2003, the vaccination rate varied from 27% to 52%. By 2014, it ranged from 82% to 91%, the study said.
Weinmann said it's not clear how long the protection against shingles will last. But over the study period, the rate of shingles cases kept declining, which may be a hopeful sign for longer protection. Still, Weinmann stressed it's too soon to know.
"The clear take home-message from this study is that the incidence of zoster in children who were immunised against chickenpox was 78% lower. So varicella vaccine prevents not only varicella, but zoster," Fagan said.
And what will happen to these children decades later, after they reach 60? Will the chickenpox vaccine have any effect on older people who have a greater risk of shingles?
Both Weinmann and Gershon said that's unknown. Until more study is done, both said there are two vaccines – Zostavax and Shingrix – available for middle-aged adults to prevent shingles.
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