Encouraging prospects for immunisation against primary cytomegalovirus infection.

Congenital cytomegalovirus (CMV) infection is the leading infectious cause of mental retardation in children. Using seroprevalence data from two large antenatal populations (in excess of 14000 women) coupled with a mathematical modelling approach, we have shown that CMV has a low force of infection (ca. 0.03 per seronegative per annum) and its basic reproductive number R0 is relatively modest at 2.4. On the basis of these results, the critical vaccination proportion required for eradication of CMV is between 59-62%. In contrast to the predicted and observed effects of rubella vaccination on the incidence of congenital rubella, the increase in the average age of infection following instigation of a CMV vaccine programme will not increase the number of congenital infections. In conclusion, CMV is a prime candidate for eradication from the human population through vaccination.