What Is Varicella?

Varicella, commonly called chickenpox, is a highly contagious infection. It is caused by the varicella zoster virus (VZV). It produces an itchy rash. It can cause serious complications, especially in adults, newborns, or people with suppressed immune systems.

VZV spreads from person to person by:

  • Airborne droplets of moisture that contain the virus
  • Direct contact with fluid from a varicella rash

It is most contagious just after the rash has broken out. It is also contagious 1-2 days before the rash erupts and until all of the blisters have crusted.

Varicella occurs most often in the late winter and early spring. It is most common in children. Peak incidence happens between ages 5-9 years. Others at risk include:

  • People who have not been vaccinated and have been in close contact with an infected person
  • People with immune deficiencies (eg, leukemia, transplantation)

Symptoms include:

  • Mild headache
  • Moderate fever
  • General feeling of malaise
  • A rash consisting of small, flat, red spots that become raised to form round, itchy, fluid-filled blisters

It takes about 10-21 days after contact with an infected person to develop varicella. The illness lasts 5-10 days. The rash usually develops on the skin above the waist, including the scalp. It may also appear on the eyelids, in the mouth, upper airway, or voice box, or on the genitals.

Treatment generally focuses on reducing itchiness, such as using anti-itch cream. For rashes that become infected, antibiotics may be used. Antiviral drugs may be given to teens and adults. For newborns and people with compromised immune systems, immune globulin is given right after exposure.

What Is the Varicella Vaccine?

This is a live virus vaccine that is given by injection. The varicella vaccine can also be given in a combination vaccine called the MMRV. This protects against measles, mumps, rubella, and varicella.

Who Should Get Vaccinated and When?

The vaccine is recommended for most children aged 12-15 months. The second dose is given between ages 4-6 years.

For those who have not been vaccinated, the Centers for Disease Control and Prevention (CDC) recommends the following schedule:

  • Up to age 13 years—2 doses, with an interval of 3 months between the first and second dose (minimum age of 12 months for the first dose)
  • 13 years and above—2 doses, with a minimum interval of 4 weeks between the first and second dose

If your child has not been vaccinated but has been exposed to chickenpox, getting vaccinated within three days can help lessen the virus or protect him from getting it.

What Are the Risks Associated With the Varicella Vaccine?

The varicella vaccine, like all vaccines, can cause problems, such as severe allergic reaction. The risk of serious harm or death is extremely small. Most people do not have any problems with the vaccine.

The most common complaints are:

  • Soreness or swelling around the injection site
  • Fever
  • Mild rash

Less commonly, seizure caused by fever, pneumonia, or other serious problems (eg, low blood count) have been reported after the vaccine.

Who Should Not Get Vaccinated?

You should not get the vaccine if you:

  • Had varicella
  • Had a life-threatening allergic reaction to gelatin, the antibiotic neomycin, or a previous dose of the varicella vaccine
  • Are pregnant—Get the vaccine after you have given birth. If you are trying to become pregnant, wait one month after getting the vaccine.

Talk to your doctor before getting the vaccine if you have the following conditions:

  • Have HIV/AIDS or another disease that affects the immune system
  • Are being treated with medicines that affect the immune system (eg, long-term steroids)
  • Have cancer
  • Had a recent blood transfusion

What Other Ways Can Varicella Be Prevented Besides Vaccination?

Avoiding contact with people who have the virus can reduce the chance of getting it.

What Happens in the Event of an Outbreak?

In the event of an outbreak, people who have not had the virus or the vaccine should be vaccinated.