Varicella-Zoster Virus (Chickenpox and Shingles)
What is varicella-zoster?
Varicella-zoster is a herpes virus that causes chickenpox, a common childhood illness. It is highly contagious. If an adult develops chickenpox, the illness may be more severe. After a person has had chickenpox, the varicella-zoster virus can remain inactive in the body for many years. Herpes zoster (shingles) occurs when the virus becomes active again.
What illnesses does varicella-zoster cause?
Chickenpox first occurs as a blister-like skin rash and fever. It takes from 10-21 days after exposure for someone to develop chickenpox. The sores commonly occur in batches with different stages (bumps, blisters, and sores) present at the same time. The blisters usually scab over in 5 days. A person with chickenpox is contagious 1-2 days before the rash appears and until all blisters have formed scabs. Children with weakened immune systems may have blisters occurring for a prolonged time period. Adults can develop severe pneumonia and other serious complications.
Shingles occurs when the virus, which has been inactive for some time, becomes active again. Severe pain and numbness along nerve pathways, commonly on the trunk or on the face, are present. Clusters of blisters appear 1 to 5 days later. The blisters are usually on one side of the body and closer together than in chickenpox. Shingles does not spread as shingles from one person to another. If people who have never had chickenpox come in contact with the fluid from shingles blisters, they can develop chickenpox.
Can you get chickenpox if you've been vaccinated?
Yes. About 15% – 20% of people who have received one dose of varicella (chickenpox) vaccine do still get chickenpox if they are exposed, but their disease is usually mild. Vaccinated persons who get chickenpox generally have fewer than 50 spots or bumps, which may resemble bug bites more than typical, fluid-filled chickenpox blisters. In 2006, the Advisory Committee on Immunization Practices (ACIP) voted to recommend routine two-dose varicella vaccination for children. In one study, children who received two doses of varicella vaccine were three times less likely to get chickenpox than individuals who have had only one dose.
Are chickenpox and shingles serious illnesses?
The symptoms may be more severe in newborns, persons with weakened immune systems, and adults. Serious problems can occur and may include pneumonia (bacterial and viral), brain infection (encephalitis), and kidney problems. Many people are not aware that before a vaccine was available, approximately 10,600 persons were hospitalized, and 100 to 150 died, as a result of chickenpox in the U.S. every year.
What should I do about an exposure to varicella?
If you have been in contact with someone with chickenpox or shingles, or if you have a rash-associated illness that might be chickenpox or shingles, discuss your situation with your healthcare provider. Blood tests may be done to see if you have become infected with the virus or have had the disease in the past. If you are pregnant and not immune and have been exposed to chickenpox or shingles, call your healthcare provider immediately. Your provider may choose to treat you with a medication called varicella-zoster immune globulin (VZIG), but in order for this medication to be most helpful, it needs to be given as soon as possible after your exposure to varicella.
I'm pregnant and have recently been exposed to someone with chickenpox. How will this exposure affect me or my pregnancy?
- Susceptible pregnant women are at risk for associated complications when they contract varicella. Varicella infection causes severe illness in pregnant women, and 10%-20% of those infected develop varicella pneumonia, with mortality (death) reported as high as 40%.
- Because of these risks, pregnant women without evidence of immunity to varicella who have been exposed to the virus may be given varicella-zoster immune globulin (VZIG) to reduce their risk of disease complications.
- If you are pregnant and have never had chickenpox, and you get chickenpox during the:
- First half (about 20 weeks) of your pregnancy, there is a very slight risk (0.4% to 2%) for birth defects or miscarriage.
- Second half of your pregnancy, the baby may have infection without having any symptoms and then get shingles (zoster) later in life.
- Newborns whose mothers develop varicella rash from 5 days before to 2 days after delivery are at risk for neonatal varicella, associated with mortality as high as 30%. These infants should receive preventive treatment with varicella-zoster immune globulin (VZIG).
I’m pregnant and have had a blood test for chickenpox. What do the results of this test show?
The blood test can show that you:
- Are immune (have already had varicella disease or varicella vaccine) and have no sign of recent infection. You have nothing further to be concerned about.
- Are not immune and have not yet been infected. You should avoid anyone with chickenpox during your pregnancy.
- Have or recently had an infection. You should discuss what the risks are for your stage of pregnancy with your healthcare provider.
Is there a way I can keep from being infected with chickenpox?
Yes, make sure all your vaccines are up to date, especially if you are planning a pregnancy. Vaccination is the best way to protect yourself and those you love. If you are not immune, you should be vaccinated. You will receive two doses of varicella (chickenpox) vaccine one month apart. You should avoid becoming pregnant for at least one month after the last vaccination. Varicella vaccine should not be given to pregnant women.
If you are pregnant, have your healthcare provider give you the varicella vaccine after your baby is delivered.
Shingles Vaccination, what you should know:
The Centers for Disease Control and Prevention (CDC) recommends shingles vaccine (Zostavax®) for people 60 years of age and older. This is a one-time vaccination to prevent shingles. There is no maximum age for getting the shingles vaccine.
Anyone 60 years of age or older should get the shingles vaccine, regardless of whether they recall having had chickenpox or not. Studies show that more than 99% of Americans ages 40 and older have had chickenpox, even if they don’t remember getting the disease.
Your risk for getting shingles begins to rise around age 50. However, shingles vaccine (Zostavax®) is only recommended for persons age 60 and older because the safety and effectiveness of the vaccine have only been studied in this age group.
Even if you have had shingles, you can still receive the shingles vaccine to help prevent future occurrences of the disease. There is no specific time that you must wait after having shingles before receiving the shingles vaccine. The decision on when to get vaccinated should be made with your healthcare provider. Generally, a person should make sure that the shingles rash has disappeared before getting vaccinated.
Additional information can be found at:
For more information, call the Missouri Department of Health and Senior Services (DHSS) at 573-751-6113 or 866-628-9891 (8-5 Monday thru Friday), or call your local health department.