Q:

7/17/2014
How soon after varicella vaccine dO the antibody titers go up? Will it be both IgG and IgM? Will commercially available test able detect post vaccination titers? Background- 2 year-old child was immigrating and received VZ on 6/17/14. He developed fever on 7/4-7/8 and rash on 7/15. On 7/17 the rash is mostly macuolopapular but has several crusted vesicles. Need to confirm if this is varicella for public health reasons and figure out how to interpret results.

A:

Thank you for your inquiry.

Antibody titers, when detectable after vaccine administration, can rise rapidly (within days). However, the issue is more complex than that since there are patients who fail to show, based on the level of sensitivity of the test, antibody responses. Both IgG and IgM, when there is a detectable response, will be present. There are commercial labs that perform anti-varicella antibody tests, and for your convenience, I have copied below links to the sites. But, my advice to you would be to contact the CDC. Below is a quote from one of their websites. I have copied below, for your convenience, the links to two websites regarding the use of tests to detect varicella. The contact information for the CDC itself is also copied for you below.

Because of the complexity in interpreting these tests, my suggestion for you would be to contact the CDC. Based on their website information, you should be able to send samples there as well as to a commercial laboratory, and the test of choice for detection of active varicella infection would be a polymerase chain reaction (PCR). I think it would be important for you to investigate the possibility of obtaining a PCR, and the websites copied below discuss this issue.

Thank you again for your inquiry and we hope this response is helpful to you.

Centers for Disease Control and Prevention
1600 Clifton Rd
Atlanta, GA 30333
800-CDC-INFO
(800-232-4636)
TTY: (888) 232-6348
Contact CDC-INFO

Varicella

CDC VARICELLA DIAGNOSIS, Interpreting Laboratory Tests

QUEST LAB

MAYO CLINIC LABORATORY

"Antibody resulting from vaccination is generally of lower titer than antibody resulting from varicella disease. Commercial antibody assays, particularly the LA test, may not be sensitive enough to detect vaccine-induced antibody in some recipients. Because of the potential for falsenegative serologic tests, routine postvaccination serologic testing is not recommended. For diagnosis of acute varicella infection, serologic confirmation would include a significant rise in varicella IgG by any standard serologic assay. Testing using commercial kits for IgM antibody is not recommended since available methods lack sensitivity and specificity; falsepositive IgM results are common in the presence of high IgG levels. The National VZV Laboratory at CDC has developed a reliable IgM capture assay. Contact the laboratory by e-mail at vzvlab@cdc.gov for details about collecting and submitting specimens for testing."

Sincerely,
Phil Lieberman, M.D.

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