Study Says Chickenpox Vaccine Should Be Given in Two Doses for It to Be Effective

chickenpox chickenpox vaccine two dose study school age

By Denise Uychiat , Parent Herald Mar 15, 06:49 am

It is recommended for school children to receive vaccine against chicken pox, and it looks like a single shot won't be enough. In a recent study, health experts reveal that children these days need at least two shots of vaccines to be able to take its full effect.

Chickenpox is a type of viral infection that is highly contagious if you haven't had the disease before or been vaccinated. It usually causes a painful and itchy rash with small, fluid-filled blisters, the U.S. Centers for Disease Control and Prevention says.

Health experts say that the first dose must be given at 1 and the second between the ages 4 to 6 years old so that the vaccine can have a 100% effective in preventing the childhood disease. Lead researcher Dana Perella of the Philadelphia Department of Public Health said, "A second dose of varicella [chickenpox] vaccine provides school-aged children with better protection against the chickenpox virus, compared to one dose alone or no vaccination," US News reports.

MedicalXpress reported that routine chickenpox vaccination started in 1995 when a lot of children were infected by the disease; some even had serious complications with it. Each year, there were at least 11,000 children who are hospitalized with the disease, and 100 deaths by chickenpox were recorded annually. The researchers found that a single dose vaccine dramatically decreased chickenpox incidence, however, schools still had outbreaks even though they had been vaccinated. The incident led the CDC to recommend a second vaccine dose.

To check the effectiveness of the double-dose vaccine, the team collected data on 125 children with the disease in Philadelphia and northern Los Angeles and compared them with 408 kids who haven't had the disease.

The results showed that the effectiveness of the two-dose vaccine were at 97 percent and higher in protecting children from chickenpox. "With improved protection provided by two-dose varicella vaccination compared with one-dose only, continued decreases in the occurrence of chickenpox, including more severe infections and hospitalizations, are expected as more children routinely receive dose 2 between the ages of 4 and 6 years," Perella said.

Following the two-dose vaccination, Perella and her team explained that the reduced number in the incident of chickenpox in the community can also protect children who have weak immune system and are not qualified to receive the vaccine.