One study shows chickenpox vaccine is associated with reduced shingles in children


The vaccine against chickenpox seems to offer benefits other than the fight against childhood disease: it could also significantly reduce the risk of herpes zoster in children, reveals a large study released Monday.

In the study published in the journal Pediatrics, researchers examined the medical records of more than 6 million children and found that those who had not received the chickenpox vaccine were four times more likely to develop shingles before the age of 17 than those who had been vaccinated. .

Chickenpox and shingles are caused by the same virus, varicella zoster virus. When a person is infected with chicken pox, the virus hides in the body and can reactivate later, causing shingles. Although shingles is most commonly seen in people 50 years of age and older with chickenpox, it can occur in children and adolescents.

The results of the massive study show that there is "a dual benefit of vaccination," said Sheila Weinmann, lead author of the study, senior researcher at the Kaiser Permanente Northwest Health Research Center. "The message for parents is that varicella vaccination reduces the risk of shingles and chickenpox in children."

This is also good news for adults who have been vaccinated against chickenpox as children. This means they will have less to worry about having shingles when they are 50 years old, experts told NBC News.

In this study, researchers examined the medical records of more than 6 million children and adolescents. About 3 million of them received the varicella or chickenpox vaccine and about 3 million did not receive this vaccine. (The large number of unvaccinated children in the study is due to the fact that many of them had not received the vaccine, introduced in 1995.)

During the 12-year study period, researchers found that about 9,044 unvaccinated children developed shingles, compared to about 5,339 of immunized children.

Another way to look at these numbers is to calculate how many children out of 100,000 would develop shingles, Weinmann told NBC News. In this regard, among the unvaccinated children, 170 out of 100,000 have developed shingles, compared to 38 out of every 100,000 children vaccinated, she said.

Varicella and shingles

Weinmann said that there were three possible explanations for why children who get vaccinated against chickenpox contract shingles.

First, you may be infected with a different strain of varicella virus after being vaccinated, and the vaccine does not protect against this strain. "No vaccine is 100% effective," said Weismann.

Secondly, you may have had chicken pox before you were vaccinated, but the case was too benign to be noticed, she said.

Finally, "the live attenuated virus in the vaccine could cause shingles," she said. (A "live attenuated virus" refers to the weakened form of the virus in the vaccine.)

An attenuated virus, such as the one used in the varicella vaccine, is a strain that has been designed to be so weak that it can not make you sick when you get the vaccine, said Dr. Tina Tan, Professor of Pediatrics at Feinberg School of Medicine at Northwestern University and Infectious Disease Specialist at Robert H. Lurie Children's Hospital. It's quite similar to the classic virus to alert your immune system and enable it to make antibodies capable of fighting it in the future, but apparently, in a small number of cases, this weakened form of the virus could cause shingles, Tan told NBC News.

But the study should reassure parents that this is very unlikely to happen.

Research "proves that the chickenpox vaccine really prevents [shingles]Tan said, who did not participate in the study. "There was an allusion to that when they did clinical trials, but with millions of kids, this study presents very solid evidence."

Dr. Nina Shapiro, a professor in the Faculty of Medicine at the University of California at Los Angeles and director of pediatric otolaryngology at UCLA, told NBC News that she was also impressed by the new discoveries.

Doctors thought that the chickenpox vaccine would reduce a person's risk of shingles later, and "this study demonstrates, with a large population, that the vaccine is very protective," said Shapiro author of "Hype: A Doctor's Guide". medical myths, exaggerated claims and bad advice – how to say what is real and what is not. "

In addition, it is likely that over time, and the percentage of older people vaccinated from childhood is greater, shingles will become less common, said Shapiro.



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