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Varicella Vaccine History

Varicella, or as it is commonly known "chickenpox", used to affect millions of people every year, especially children. According to the CDC, before the vaccine came into routine use in 1995, almost every individual in the United States had been infected by adulthood. Because of that, for many people, chickenpox was merely a part of growing up, something that a person would probably get at some point before reaching adulthood. Things have changed though because now there is a vaccine against varicella available, and it is increasingly being used throughout the population.

  1. What Is Varicella?

    • According to the CDC, a Varicalla infection is caused by the varicella zoster virus.The virus is spread through coughing and sneezing, thus making it airborne and highly contagious. It is also spread through direct contact and when the virus becomes aerosolized from skin lesions.
      The characteristic symptoms of varicella are a severe rash with red bumps and eventually blisters that form all over the surface of the skin. Inmunizationinfo.org notes that "a child will often get 300 to 500 blisters during the infection, which crust over and fall off in one to two weeks." This makes the infection quite unpleasant because patients will often want to scratch at the blisters but are unable to do so due to the secondary infections that can result. The rash is also usually accompanied by a fever.

    Complications from Varicella

    • While normally not deadly, the disease does have the potential to cause further problems. Less than 1 out of every 10,000 cases result in death, and pneumonia in 23 out of every 10,000 cases. Other issues include a 2 percent chance of birth defects in fetuses where the mother contracted varicella early in the pregnancy.

    High Risk for Adults

    • As mentioned, the varicella virus is not usually problematic for children beyond the average two week long infection. More concern is given to adults who are infected because they account for 35 percent of the deaths associated with the disease. That, and the high rate of infection, was a large factor in motivating scientists to develop the vaccine.

    Development of the vaccine

    • The vaccine was initially developed in Japan in the 1970s by isolating the "Oka" strain of the varicella zoster virus from a 3-year old boy. It came into routine use in Japan and Korea when it was licensed in 1988. It was not until 1995 though that the vaccine was approved and recommended for use in the United States. Since that time, the New England Journal of Medicine reports that mortality rates associated with the disease have dropped significantly since the introduction of universal childhood vaccination. As of 2005, a combined mumps, rubella, varicella vaccine (MMRV) was licensed, allowing for easier and quicker inoculation. Other studies have been conducted internationally with similar results.

    Current Adminstration and Known Side Effects

    • Currently, a varicella vaccination is part of the mandatory immunization entry requirement for school aged children in many states throughout the country. As of 2006, a two dose vaccination is recommended for all individuals who do not show evidence for immunity or do not otherwise have any allergies. Like every other vaccine, there are potential side effects associated with taking the varicella vaccine. These include soreness and rash at the injection site, and possible fever in as many as 15 percent of children receiving it.

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