Chickenpox is significantly more dangerous for adults than for children. Before the vaccine became widespread in the United States, adults accounted for fewer than 10% of chickenpox cases but roughly 30% of hospitalizations and about half of all deaths. An adult who catches chickenpox faces a higher risk of serious complications, a longer and more miserable illness, and a slower recovery than a child with the same infection.
Why Adults Get Sicker Than Children
In children, chickenpox is usually a mild, self-limiting illness: an itchy rash, a low fever, and a week of missed school. In adults, the immune system mounts a more aggressive inflammatory response to the varicella-zoster virus, which paradoxically makes the disease worse. Adults tend to develop more blisters, higher fevers, and deeper fatigue. The rash often lasts longer and leaves more noticeable scars.
The real concern, though, isn’t the rash. It’s the complications that adults are far more likely to develop.
Pneumonia: The Most Common Serious Complication
Varicella pneumonia is the complication that sends the most adults to the hospital. The virus spreads from the skin into the lungs, causing inflammation that can progress to difficulty breathing within a few days of the rash appearing. Symptoms include cough, chest tightness, rapid breathing, and sometimes bloody sputum.
Without antiviral treatment, varicella pneumonia has historically carried a mortality rate around 19%. With prompt antiviral therapy, that drops to roughly 6%, according to data published in the European Respiratory Journal. That’s still a serious number for what many people think of as a childhood nuisance. Smokers and people with lung conditions face an even higher risk of developing this complication.
Brain and Nervous System Complications
The varicella-zoster virus can also invade the central nervous system, leading to encephalitis (brain inflammation), meningitis, or a condition called cerebellar ataxia that causes problems with balance and coordination. These neurological complications are rare but can be severe, sometimes causing lasting damage. Symptoms to watch for include intense headache, confusion, stiff neck, seizures, or difficulty walking during or shortly after a chickenpox infection.
Skin infections are another risk. The open blisters create entry points for bacteria, which can lead to cellulitis or, in serious cases, bloodstream infections.
Chickenpox During Pregnancy
Pregnant women who contract chickenpox face a particularly dangerous situation. The risk of varicella pneumonia is higher during pregnancy, and some evidence suggests it’s most severe when the infection occurs in the third trimester.
There are also direct risks to the baby. If a pregnant woman gets chickenpox during the first or early second trimester, the baby has a 0.4% to 2.0% chance of being born with congenital varicella syndrome, a condition that can cause skin scarring, limb abnormalities, brain and eye defects, and low birth weight. Infection very close to delivery is also dangerous because the newborn can develop severe chickenpox without the benefit of protective antibodies from the mother.
What to Do If You’re Exposed
If you’re an adult without immunity and you’ve been exposed to someone with chickenpox, time matters. There are two main options depending on your situation.
For healthy, non-pregnant adults, the chickenpox vaccine can still help if given soon after exposure. Getting vaccinated within three to five days of contact may prevent infection entirely or significantly reduce its severity.
For people who can’t receive the vaccine (pregnant women, those with weakened immune systems), a treatment called VariZIG, which contains antibodies against the virus, can be given. The CDC recommends it as soon as possible after exposure, ideally within 96 hours, though it can be administered up to 10 days after contact.
Treatment Once Symptoms Start
If you develop chickenpox as an adult, antiviral medication is typically recommended. The standard treatment works best when started within 24 hours of the rash first appearing, so don’t wait to see if it gets worse. The medication doesn’t cure the infection, but it can reduce the number of blisters, shorten the duration of illness, and most importantly, lower the risk of serious complications like pneumonia.
Beyond antivirals, treatment is largely supportive: calamine lotion or oatmeal baths for itching, fever reducers (though not aspirin, which can cause a rare but serious condition called Reye’s syndrome), and staying hydrated. Most adults recover within two to four weeks, though fatigue can linger.
Who’s Most at Risk
Not every adult faces the same level of danger. The groups at highest risk for severe chickenpox include:
- Pregnant women, especially in the third trimester
- People with weakened immune systems, including those on immunosuppressive medications, chemotherapy, or living with HIV
- Smokers, who are more likely to develop varicella pneumonia
- Adults over 50, who tend to have more severe illness and slower recovery
Even healthy adults in their 20s and 30s, though, can develop serious complications. The risk isn’t limited to people with obvious vulnerabilities.
Vaccination for Adults Without Immunity
The most effective protection is vaccination. Adults 13 and older who have never had chickenpox and haven’t been vaccinated should receive two doses of the varicella vaccine, spaced four to eight weeks apart. If more than eight weeks pass between doses, you don’t need to restart the series.
Most adults born before 1980 in the United States are assumed to have had chickenpox as children, even if they don’t remember it, since the virus was so widespread before the vaccine era. If you’re unsure, a blood test can check for antibodies. Adults born after 1980 who don’t have a clear history of the disease or vaccination are the most likely to lack immunity and should seriously consider getting vaccinated.
The vaccine is a live virus vaccine, which means it’s not appropriate for pregnant women or people with significantly weakened immune systems. If you received VariZIG after an exposure, you’ll need to wait at least five months before getting vaccinated.
The Shingles Connection
Even after you recover from chickenpox, the varicella-zoster virus never fully leaves your body. It goes dormant in nerve cells and can reactivate decades later as shingles, a painful blistering rash that follows a nerve path. About one in three people who had chickenpox will eventually develop shingles, and the risk increases with age. Adults who get chickenpox later in life carry this same long-term risk, which is one more reason prevention through vaccination matters.