From the Guidelines
Varicella zoster virus (VZV) antibodies IgG and IgM are crucial for determining immune status and guiding management decisions, particularly in immunocompromised patients or those with suspected reactivation (shingles).
Key Points
- IgM antibodies appear first, typically within 1-2 weeks after initial infection, indicating a current or very recent primary VZV infection (chickenpox) 1.
- IgG antibodies develop more slowly, becoming detectable 2-3 weeks after infection, but persist for life, providing long-term immunity against reinfection.
- The presence of VZV IgG without IgM typically indicates past infection or vaccination and subsequent immunity.
- Testing for these antibodies helps determine immune status, diagnose current infections, and assess vaccination needs, especially in susceptible individuals such as pregnant women without VZV IgG who should avoid exposure to chickenpox 1.
- Healthcare providers use these antibody tests to guide management decisions, particularly for immunocompromised patients or those with suspected reactivation (shingles), and may recommend post-exposure prophylaxis for seronegative patients 1.
Clinical Application
- Patients without a clear history of chickenpox, shingles, or receipt of two doses of varicella vaccine should be tested for VZV IgG 1.
- Seronegative patients should receive timely post-exposure prophylaxis and, where possible, complete the two-dose course of varicella vaccine at least 3 weeks prior to commencement of immunomodulator therapy 1.
- Subsequent immunization can only be administered after a 3–6 month cessation of all immunosuppressive therapy 1.
Evidence-Based Recommendation
The most recent and highest quality study 1 supports the screening of patients for susceptibility to primary VZV infection at diagnosis of inflammatory bowel disease (IBD) and recommends vaccination for seronegative patients prior to immunomodulator therapy. This approach prioritizes morbidity, mortality, and quality of life by preventing VZV infections in vulnerable populations.
From the Research
Varicella Zoster Virus Antibodies
- Varicella zoster virus (VZV) antibodies, including IgG and IgM, are indicators of immunity to varicella and protection from chickenpox 2.
- The presence of VZV antibodies in serum indicates immunity to varicella, although the role of specific antibody in mediating protection remains unclear 2.
- Both IgM and IgG antibodies to VZV are detectable in a solid-phase radioimmunoassay, with primary infection associated with early production of IgM and IgG antibodies 3.
IgG and IgM Responses
- IgG antibodies to VZV are associated with long-term immunity, while IgM antibodies are indicative of recent or acute infection 3, 4.
- The IgM response to VZV is observed following chickenpox and zoster, and to a lesser extent, in recipients of VZV vaccine 4.
- High titers of VZV IgM antibody can be detected in unfractionated sera despite the presence of high titers of VZV IgG antibody 3.
Diagnostic Usefulness
- VZV-specific IgA and IgG antibodies can be used to diagnose herpes zoster, with significantly higher median VZV IgG antibody titers observed in patients with herpes zoster compared to healthy controls 5.
- A four-fold or higher increase in VZV IgG antibody titer can be observed in some patients with herpes zoster, although this is not detected in a satisfactory proportion of patients 5.