The chickenpox vaccine protects you against the varicella-zoster virus, which causes chickenpox. Chickenpox spreads very easily and can lead to serious problems, mainly in adults, pregnant women, newborns, and people with weak immune systems. In this detailed guide, you will learn what chickenpox is, how the vaccine works, who should get it, how many doses you need, its side effects, and when you should not have it.
What Is Chickenpox?
Chickenpox is a viral infection that causes an itchy, blister-like rash, fever, and tiredness. A person with chickenpox is contagious from one to two days before the rash appears until all blisters have formed scabs, usually about five to seven days later. The virus spreads through coughs, sneezes, and direct contact with the blister fluid. About 90 percent of people who are close to an infected person and have no immunity catch it.
Symptoms
- A rash that starts as red spots, turns into fluid-filled blisters, and then forms scabs
- Fever, usually mild to moderate
- Headache, tiredness, and loss of appetite
- Itching, which can be intense
Symptoms usually appear 10 to 21 days after contact.
Possible Complications
Chickenpox is often mild in children, but it can cause:
- Skin infections: Scratching can lead to bacterial infection and scarring.
- Pneumonia: It is more common in adults.
- Encephalitis: inflammation of the brain
- Dehydration
- Serious illness in pregnancy: It can harm the mother and the baby.
- Severe disease in newborns whose mothers had chickenpox just before or after birth
- Shingles later in life: The virus stays in the nerves and can wake up years later.
How Does the Vaccine Work?
The vaccine contains a weakened (live) form of the virus. It teaches your immune system to recognize and fight the virus without causing the full illness. Your body then makes antibodies that protect you if you meet the real virus. Doctors sometimes combine it with the measles, mumps, and rubella vaccine (MMRV).
Vaccine Brands and Types
Several brands exist, including Varivax and Varilrix. The MMRV combination (such as ProQuad) gives protection against four diseases in one shot. The exact brands available depend on your country, so ask your doctor.
History of the Chickenpox Vaccine
Japanese scientist Michiaki Takahashi developed the vaccine in the 1970s using the Oka strain of the virus. Several countries began using it in the 1990s. In the United States, routine childhood vaccination began in 1995 and has cut hospital stays and deaths from chickenpox sharply. Many countries now include it in their routine schedule.
Who Should Get the Vaccine?
- Children: Doctors usually give two doses. The first dose is at 12 to 15 months, and the second is at 4 to 6 years. The second dose can be given earlier, at least three months after the first.
- Teenagers and adults without immunity: They need two doses, given four to eight weeks apart.
- High-risk adults: Healthcare workers, teachers, childcare workers, college students, international travelers, and people who live with young children or with someone with a weak immune system should get vaccinated if they are not immune.
- Women who plan to become pregnant: They should be vaccinated before pregnancy if they are not immune. Wait at least one month after the vaccine before you try to conceive.
You count as immune if you have written proof of two doses, proof of past chickenpox from a doctor, or a positive blood test. Ask your doctor or local immunization program about availability and the schedule that suits you.
Vaccine After Contact With Chickenpox
If a person without immunity meets someone with chickenpox, the vaccine given within three to five days (the sooner, the better) can prevent the disease or make it milder. Doctors may also give antibody injections to high-risk people who cannot get the vaccine.
How Well Does It Work?
- One dose prevents most cases of chickenpox, about 8 or 9 in 10, and almost all severe cases.
- Two doses protect about 9 in 10 people from any chickenpox, and almost all from severe disease.
- Breakthrough chickenpox: Some vaccinated people still get a mild form of the disease, with fewer than 50 spots, a low fever, and a shorter illness.
Protection is long-lasting, and booster doses are not needed for healthy people.
Side Effects
Most side effects are mild and short:
- Soreness, redness, or swelling where you had the shot, in about 1 in 5 people
- Mild fever, in about 1 in 10 people
- A mild rash with a few spots, in about 1 in 25 people, which can spread the vaccine virus rarely
Serious side effects are rare. They include:
- An allergic reaction
- A seizure linked to fever
- Pneumonia or brain infection, which are extremely rare
Who Should Not Get the Vaccine?
- Pregnant women, and women who plan to become pregnant within one month after the shot
- People with a severely weak immune system, such as people receiving chemotherapy or high-dose steroids, or people with severe HIV
- People who had a severe allergic reaction to a previous dose or to gelatin or neomycin
- People with a moderate or severe illness, until they recover
- People who recently had a blood transfusion or immune globulin, who may need to wait a few months
Tell your doctor about all your medical conditions before the shot.
Chickenpox Vaccine and Shingles
The vaccine strain can also stay in the body, but it is less likely than natural chickenpox to cause shingles later in life. Adults over 50 can get a separate shingles vaccine.
Why Not Let Children Catch Chickenpox Naturally?
Some people think it is better to get chickenpox as a child. This is risky. You cannot predict who will get severe disease, and even healthy children can have serious complications. The vaccine gives protection with far fewer risks and also protects people who cannot be vaccinated.
Chickenpox Vaccine in Pakistan
In many countries, including Pakistan, the chickenpox vaccine is not part of the routine government schedule, and families usually buy it from private clinics. Ask your pediatrician about the schedule and where to get it.
How to Care for a Child With Chickenpox
If your child gets chickenpox:
- Keep your child at home until all blisters have formed scabs.
- Use paracetamol for fever. Do not give aspirin.
- Trim fingernails short to reduce scratching.
- Use calamine lotion or cool baths to ease itching, and ask your doctor about antihistamines.
- Keep your child away from newborns, pregnant women, and people with weak immunity.
- Call your doctor if the rash becomes red, warm, or swollen, if the fever is high, or if your child is very sleepy or has trouble breathing.
High-risk patients may need an antiviral medicine, such as acyclovir, started early.
Chickenpox in Pregnancy and Newborns
Chickenpox during pregnancy can cause pneumonia in the mother. Infection in early pregnancy can rarely harm the baby, and infection around delivery can cause severe disease in the newborn. A pregnant woman without immunity who meets someone with chickenpox should call her doctor right away. Doctors can give protective antibodies. Women who plan pregnancy should check their immunity first.
Common Myths About the Chickenpox Vaccine
- “The vaccine gives you chickenpox.” It almost never does. When a rash appears, it is mild and has only a few spots.
- “Natural infection is better.” Natural infection carries a real risk of serious problems, and it can cause shingles later.
- “Vaccinated children cannot spread it.” Vaccinated people rarely spread it, but a mild breakthrough case can still spread the virus.
- “I had it as a child, so I need no vaccine.” If a doctor confirmed it, you are usually immune and do not need the vaccine.
Chickenpox Vaccine and Breastfeeding
You can breastfeed after you get the vaccine. The vaccine virus does not pass into breast milk in a way that harms the baby. Ask your doctor if the baby is premature or has a weak immune system.
Tips for the Day of the Vaccine
- Tell the doctor about any fever, allergy, or medicine you take.
- Stay for 15 minutes after the shot, in case of a rare allergic reaction.
- Use a cool, damp cloth on a sore arm.
- Give paracetamol for fever if the doctor advises it. Avoid aspirin in children.
- Call your doctor if you notice a high fever, a widespread rash, or trouble breathing.
Frequently Asked Questions
How many chickenpox vaccine doses are needed?
Two doses give the best protection.
Can adults get the chickenpox vaccine?
Yes. Adults without immunity need two doses, four to eight weeks apart.
Can I get chickenpox after the vaccine?
Yes, but it is usually much milder.
Is the chickenpox vaccine safe in pregnancy?
No. It is a live vaccine. Avoid it in pregnancy and wait one month after the shot before trying to conceive.
How long does the vaccine last?
Protection is long-lasting, and healthy people do not usually need a booster.
Can the vaccine cause chickenpox?
Rarely, a mild rash with a few spots appears. Severe disease from the vaccine is extremely rare.
Disclaimer: This article is for information only. It is not medical advice. Please talk to your doctor about your own health.