What Is CMV?
Cytomegalovirus (CMV) is a very common herpesvirus. Most healthy adults who become infected have no symptoms or mild flu-like illness. Like EBV, CMV remains latent for life. It only causes serious disease in immunocompromised people (transplant recipients, HIV) and when transmitted during pregnancy.
CMV Antibody Tests
| IgM | IgG | Interpretation |
|---|---|---|
| − | − | Never infected — susceptible |
| + | −/+ | Active or recent primary CMV infection |
| − | + | Past infection — immune; latent CMV |
| + | + | Could be reactivation, reinfection, or recent primary — CMV PCR needed to confirm active infection |
When Is CMV Testing Important?
- Pregnancy — primary CMV in pregnancy can cause congenital hearing loss, developmental delay and microcephaly in the baby
- Organ or bone marrow transplant recipients — CMV reactivation is a major complication
- HIV/AIDS — CMV can cause retinitis (blindness) and colitis at low CD4 counts
- Unexplained mononucleosis-like illness where EBV is negative
Congenital CMV
The most common congenital infection in the developed world. Most babies are asymptomatic at birth but ~15% develop hearing loss or developmental problems later. Pregnant women who are CMV IgG negative are most at risk from new infection.
FAQs
Can CMV be treated?
In immunocompromised patients, antiviral drugs (ganciclovir, valganciclovir) are used. Healthy individuals do not need treatment.
How is CMV spread?
Through saliva, urine, breast milk, blood, sexual contact, and organ transplants.
Is there a CMV vaccine?
No licensed vaccine yet, but several are in clinical trials.
Medical Disclaimer: CMV during pregnancy requires specialist obstetric management. Immunocompromised patients with active CMV should be managed by an infectious disease specialist.