An audit of rubella IgG antibody status in antenatal women in a NHS Trust over 5 years (2005-2009).

Rubella, a vaccine-preventable infection. This study examined the antibody status of 11 987 pregnant women during 2005-2009. Results showed a non-significant decrease in those with antibody levels of <4·0 IU/ml from 29/2312 (1·3%) in 2005 to 21/2447 (0·9%) in 2009 (χ² for linear trend=0·279, P=0·56) but a significant increase in those with levels of <10 IU/ml from 88/2312 (3·8%) in 2005 to 124/2447 (5·1%) in 2009 (χ² for linear trend=10·27, P=0·001). In women born before 1983 (pre-pubertal vaccination) the proportion of first pregnancies with titres <4 IU was 1·1% (21/2002) compared to 3·4% (69/2022) in those born after 1983 (χ²=25·176, P<0·0001) and 2·2% (44/2002) for titres <10 IU compared to 14·0% (282/2022) for those born after 1983 (χ²=171·43, P<0·0001). The potential impact of the increase is difficult to determine, requiring further monitoring. This paper discusses the effect of changing immunization programmes on rubella susceptibility in pregnant women.