Dr. Vaccines
Varicella (Chickenpox) Serology Test
A blood test that settles whether you had chickenpox, because family recollection is not reliable enough to act on.
A varicella serology test measures IgG antibodies to varicella zoster virus, the virus that causes chickenpox. A positive result means you are immune, either from having had the infection or from vaccination.
The reason this test exists is that self-reported history is unreliable. Plenty of people are certain they had chickenpox and turn out not to be immune; others have no memory of it and test positive, having had a case mild enough that nobody noticed. When the consequences matter, a pregnancy, a healthcare job, a university requirement, a blood test is worth more than a family recollection.
At a glance
| Vaccine or test | Status | Schedule | Detail |
|---|---|---|---|
| Varicella zoster IgG | Recommended | Single blood sample | A positive result indicates immunity from past infection or vaccination. This is the test itself, not a vaccine. |
| Varicella vaccine | Conditional | Two doses, 4 to 8 weeks apart, if non-immune | A live attenuated vaccine, so it cannot be given during pregnancy or in significant immunosuppression. If you are planning a pregnancy and test negative, have the doses beforehand and allow about a month before conceiving. |
| Shingles vaccine | Conditional | A different vaccine, from age 50 | Frequently confused with this one. The varicella vaccine prevents chickenpox in people who never had it. The shingles vaccine prevents reactivation in people who did. They are not interchangeable. |
Chickenpox in adults is a different illness
In young children chickenpox is usually a week of itching and a few days off school. In adults it is substantially more severe, with a higher rate of pneumonia, hepatitis and encephalitis, and a genuine risk of hospitalisation.
That gradient is why adult immunity is worth confirming rather than assuming. An adult who has escaped chickenpox has not had a lucky run. They are carrying a meaningful susceptibility to a more dangerous version of the disease.
When this test is required
Most requests come from one of a few situations.
- University admission abroad, where varicella immunity sits alongside MMR on the requirement list.
- Healthcare and childcare employment, where staff must not be susceptible.
- Before a planned pregnancy: chickenpox in pregnancy risks both mother and baby.
- Before starting immunosuppressive treatment, since the live vaccine must be given beforehand if needed.
- After exposure to someone with chickenpox or shingles, when immunity status is unknown.
Pregnancy is the situation with the tightest timing
Chickenpox during pregnancy can cause severe maternal illness, and infection in early pregnancy carries a small risk of congenital varicella syndrome. Infection around the time of delivery is dangerous for the newborn.
Because the vaccine is live, none of this can be addressed once you are pregnant. Testing before conception, and vaccinating if needed with about a month before trying, is the only way to close that gap.
Varicella and shingles are the same virus
After chickenpox resolves, varicella zoster virus stays dormant in nerve tissue for life. Shingles is that same virus reactivating decades later. Being immune to chickenpox therefore does not protect you from shingles, if anything, having had chickenpox is the prerequisite for it, which is why the shingles vaccine is recommended from 50 regardless of your varicella serology result.
Frequently asked questions
What does a varicella IgG test tell me?
Whether you are immune to chickenpox, from past infection or vaccination. A positive IgG result indicates immunity; a negative result means you are susceptible and should consider the two-dose vaccine.
I am sure I had chickenpox as a child. Do I still need testing?
If the answer matters: a pregnancy, a healthcare job, a university requirement, yes. Self-reported history is unreliable in both directions: some people who are certain they had it are not immune, and some with no memory of it are.
What if the test comes back negative?
Two doses of varicella vaccine, four to eight weeks apart. It is a live vaccine, so it must be completed before pregnancy or before starting immunosuppressive treatment, not during either.
Is chickenpox worse in adults?
Considerably. Adults have higher rates of pneumonia, hepatitis and encephalitis, and are more likely to be hospitalised. That is why confirming immunity in adulthood is worthwhile rather than assuming it.
Does being immune to chickenpox protect me from shingles?
No: it is the opposite. Shingles is the chickenpox virus reactivating after lying dormant in nerve tissue. Having had chickenpox is what makes shingles possible, which is why the separate shingles vaccine is recommended from age 50.
Book your varicella immunity test
One blood sample settles it. If you are not immune, we can start the two-dose vaccine course straight away, which matters most before a pregnancy or immunosuppressive treatment.
Before you rely on this page
This page is general health information, not personal medical advice. Vaccine schedules depend on your age, medical history, pregnancy status, medications and previous immunisations. Our doctors will confirm what is right for you at your appointment. National recommendations are also revised periodically. We review these pages against current Indian and WHO guidance.
Last reviewed: 2026-09-01
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