I was having sex with a sex worker and when i inserted my penis into her anus the condom broke and I immediately pulled out. She said she was hiv negative. Should i consider PEP or not worry at all?

1.  Most commercial sex workers do not have HIV or other STIs.  While there is a range with some being lower risk, most CSWs, and particularly those who work through web sites or brothels, test regularly and take precautions to avoid infection.  Less than 1% of CSWs in North America have HIV.

2.  The risk of acquiring an STI varies with different STIs but the likelihood of transmitting any STI by an infected woman is never higher than 1 in 10-20 for STIs like gonorrhea and for HIV, on average fewer than 1 in 2000 exposures to an untreated infected partner results in infection ( I.e. in the unlikely situation that she had untreated HIV chances are more that 99.95% that you would NOT become infected.

3.  Your exposure was quite brief.  Logically the shorter the exposure, the lower the risk.

4.  She said she was negative.  Most people tell the truth.

You may wish to get tested.  Testing for gonorrhea and chlamydia can be conclusively tested for at any time more than 3-4 days after your exposure.  Testing for syphilis and HIV will take longer to provide conclusive results- 6 weeks but your risk for these infections is also much, much lower as well.

Odds are VERY high that you were not infected.  I hope that the information I’ve provided is helpful.  EWH