Introduction A PEP indication is an ideal opportunity for safe sex promotion and STI screening. Since 2010 the STI outpatient clinic in Amsterdam, the Netherlands, offers PEP to HIV negative men who have sex with men (MSM) who had unprotected receptive anal intercourse within the last 72 hours. If STI screening is performed at the moment of PEP request, early incubating chlamydia and gonorrhoea infections acquired during the unsafe sex act, are possibly missed. We aimed to determine if chlamydia and gonorrhoea screening should be repeated in MSM 2 weeks after a PEP indication.

Methods We included all MSM visiting the STI clinic with a PEP request in the period from April 2010 until December 2012. STI testing was offered to all MSM during the PEP evaluation visit. Men were screened for urethral, anal and pharyngeal infections based on their practised sex techniques. If PEP was indicated a visit was planned 2 weeks later to repeat gonorrhoea, and chlamydia screening.

Results 447 consultations MSM requested PEP and in 325 (72.7%) PEP was indicated. In 50/325 (15%) cases at least one STI was diagnosed at the moment of PEP indication. 172 (52.9%) cases returned after 2 weeks of whom in 9 (5.2%) cases at least one previously undiagnosed infection was found (3 rectal chlamydia, 3 rectal gonorrhoea, 2 rectal chlamydia/gonorrhoea double infections, and 1 pharyngeal chlamydia).

Conclusion Repeated chlamydia and gonorrhoea screening 2 weeks after a PEP indication in MSM revealed 5.2% additional, possibly early incubating, infections. Yet, 47.1% of MSM did not show up for the second screenings visit. Therefore STI screening should be offered at the PEP indication visit and preferably repeated after 2 weeks to exclude early incubating chlamydia and gonorrhoea infections.