Preventing CMV Through Hygiene
Why the ambivalence toward hygienic practices? Studies have shown that transmission of CMV via the urine and saliva of children is a major cause of infection among pregnant women. In addition, more than 100 years of evidence conclusively demonstrates that hand washing reduces risk of infection for a wide range of pathogens. Thus, nearly everyone would agree that, in theory, hand washing can prevent CMV infection because hands are an important vehicle for transmission. The concern, then, is not the efficacy of hygienic practices (i.e., Will they work if consistently followed?) but, instead, the effectiveness of interventions to promote them (i.e., Will women consistently follow hygienic practices as the result of interventions?).
It is important to recognize the implications of the consensus that hygienic practices are efficacious for preventing CMV transmission. Individual women have the right to know that, under ideal conditions, risk of child-to mother CMV transmission can be reduced by proper hygienic practices. This is equivalent to the ethical obligation to inform individuals that, under ideal conditions, safer sexual practices will reduce the risk of acquiring HIV. This obligation is independent of whether any particular educational program or intervention is effective. All women of childbearing age, whether they are CMV seropositive or seronegative, carry some risk of new CMV infection during pregnancy and thus should be informed of hygienic practices that reduce that risk.
The terrible burden of congenital CMV disease should make the provision of such information a priority. As there is consensus on the efficacy of hygienic practices in preventing CMV transmission, the next step is to evaluate the effectiveness of educational interventions in preventing CMV transmission. Current evidence of effectiveness is promising, but limited. In one study, after non-pregnant women were educated about CMV prevention, hygienic practices improved. In a small study of Houston families, Demmler and colleagues found that behavioral changes prevented transmission of CMV (unpublished report). Adler and colleagues and others studied the effectiveness of hygienic practices in a randomized, controlled trial and found significant differences in infection rates between the intervention and control groups, seroconversion rates decreased as CMV education and support increased. Thus, pregnant women who receive an intervention involving hygienic practices are significantly less likely to acquire CMV infection than were non-pregnant women.
More conclusive evidence of effectiveness can be found in the literature on community-based interventions for the prevention of other infectious diseases with similar transmission modes. For example, a meta-analysis found that community intervention trials that encouraged washing hands with soap reduced the risk of diarrheal diseases by 47%. Hand-washing programs reduced respiratory illness among military recruits and children in daycare, and interventions involving hand sanitizers reduced absenteeism among elementary school teachers and children.
Although all women of childbearing age deserve to be informed about CMV, interventions for preventing CMV transmission are most likely to be effective for pregnant women, who tend to be highly motivated, often changing behavior to protect the health of their developing fetuses. As a case in point, 25% of low-income smokers spontaneously quit smoking during pregnancy; this percentage is higher than that achieved by most smoking cessation programs. In sum, the evidence to date gives every indication that effective interventions can be found for preventing CMV infection among pregnant women. Thus, the paradigm must shift from wondering whether such interventions will be effective to developing and evaluating interventions until effective ones are identified.