Rubella immune status of pregnant and non-pregnant women in Istanbul, Turkey

Rubella immunization rates are not optimal and infections during pregnancy still occur since many countries incorporate no rubella vaccine in their national immunization program. The evaluation of immunity to rubella virus relies on the presence of specific antibodies. This study was undertaken to determine in a cross-sectional survey whether rubella virus circulation in the Istanbul city, induces detectable immunoglobulin G (IgG) antibodies with a protective level, in a random group of pregnant and non-pregnant women. One hundred and sixty women of 20-41-years of age (average 24-years) were grouped as follows: 1. Forty-eight married women. Among these were 41 pregnant women (33 delivered normally, 8 aborted). 2. One hundred and twelve single women. Samples were collected during the periods from October 2000 through to March 2001 and from November 2001 through to May 2002. Rubella specific IgG antibodies were detected (by the ELISA test) in all women tested. Quantitative analysis of the IgG levels showed noticeable variability that ranged between 24-143 IU/ml (average 94). One hundred and forty-five (91%) out of 160 women had rubella IgG levels of above 50 IU/ml with a range of 54-143 IU/ml (average 92) while 15 (9%) had a level between 24-46 IU/ml (average 38). Rubella IgG-avidity test revealed that 116 (73%) of women had high IgG avidity, 22 (14%) had intermediate avidity and 20 (13%) showed low avidity. Two women who were IgM positive, each had either high or intermediate IgG avidity. All women tested were seropositive for rubella specific IgG antibodies suggestive of natural virus circulation within the community. Although the majority appeared to possess protective level of such antibodies, screening for protective immunity appears always to be a necessity for future protection against reinfection.