Prevention of fetal infection
Since routine antepartum screening has not been implemented, at least previously seronegative pregnant women or willing to become pregnant should be informed about the preventive hygienic measures to avoid CMV transmission mostly from children under 3 years of age. In our opinion, pregnant women should be screened for CMV antibodies at least twice (i.e. at 8-10 and 14-16 weeks’gestation) to identify a seroconversion in previously seronegative women, or a reactivation/reinfection shown by significant IgG increase possibly concomitant with positive IgM antibodies in previously seropositive women. The screening would automatically lead to know well CMV in pregnancy and support researches for prevention (vaccines) and therapy (immunotherapy, antivirals).
Seronegative pregnant women should be instructed in frequent handwashing after handling diapers and material contaminated with secretions and cautioned about the potential risk of intimate contact, especially mouth-to-mouth (i.e. kisses, sharing food, drink or flatware).
Prevention or treatment of fetal infection by HIG
Commercially available HIG is manufactured from plasma of at least 1000 selected donors with high anti-CMV antibody titers and has a high neutralizing capacity since contain a high concentration of all human antibodies against CMV, including anti-trimer and anti-pentamer blocking antibodies. In addition, HIG displays modulatory activities on the complement system, cytokine production and activity, expression of Fc receptors, and lymphocyte activation. These effects decrease the inflammatory tissue damage in response to the replication of CMV. Although maternal CMV-seropositivity prior to pregnancy does not provide full protection against prenatal infection and disease, treatment of pregnant women with CMV-specific HIG may be effective in prevention of congenital CMV infection. Moreover, several papers and case reports evidenced that HIG administration can decrease the severity of CMV-associated fetal anomalies.
Adverse effects of HIG
Manufacturing processes of HIG include virus inactivation and removal steps such as cold-ethanol fractioning, solvent-detergent treatment, incubation at low pH, pasteurization, and nanofiltration. In all but two reported studies, HIG infusions were safe and well-tolerated.