Seropositivity to multiple sexually transmitted infections is not common.
BACKGROUND
Seropositivity for several sexually transmitted infections (STIs) is often used as a surrogate measure of sexual behavior. The authors assessed the concomitant seropositivity for STIs in women.


OBJECTIVE
To estimate the excess of concomitant seropositivity for four STIs among fertile-aged women assuming no coinfections above what would be expected at random.


METHODS
Antibodies to herpes simplex virus type 2, human papillomavirus type 16, HIV, Chlamydia trachomatis, and Treponema pallidum were determined from a random sample of 1110 pregnant women in Tallinn, Estonia.


RESULTS
A total of 310 combinations of the concomitant seropositivity were observed, whereas only 193 were expected by chance. Among persons seropositive for two STIs, 78 extra combinations were observed, whereas for three STIs, 35 extra combinations were observed. For four STIs, 3.8 extra combinations were found.


CONCLUSIONS
Seropositivity to multiple STIs is not common. This fits the concept of different transmission probabilities and the spread of the STIs, and suggests that seropositivity alone should be used with caution as a surrogate to sexual behavior in women.
Kibur
M
M
Department of Epidemiology and Biostatistics, Institute of Experimental and Clinical Medicine, Tallinn, Estonia. mari.kibur@ktl.fi
Koskela
P
P
Dillner
J
J
Leinikki
P
P
Saikku
P
P
Lehtinen
M
M
Hakama
M
M
D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D004957:Estonia / Q000453:epidemiology; D005260:Female; D006801:Humans; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D016036:Seroepidemiologic Studies; D012725:Sexual Behavior; D012747:Sexual Partners; D015231:Sexually Transmitted Diseases, Bacterial / Q000145:classification / Q000453:epidemiology* / Q000635:transmission; D015229:Sexually Transmitted Diseases, Viral / Q000145:classification / Q000453:epidemiology* / Q000635:transmission
D000907:Antibodies, Bacterial; D000914:Antibodies, Viral