Number of STI cases, number of MSM tested and positivity by the six latent classes of MSM attending CSH (n=13 516)*
| Class 1 | Class 2 | Class 3 | Class 4 | Class 5 | Class 6 | ||
| Lower risk | Intermediate risk | High risk | |||||
| Overall low risk | Western origin and MSP | Non-Western origin and MSP | Living with HIV | Group sex and HIV-positive partners | Group sex and chemsex | ||
| n | 2974 | 4182 | 2496 | 827 | 1798 | 1239 | |
| % | 22.0 | 30.9 | 18.5 | 6.1 | 13.3 | 9.2 | |
| Any STI | n/N | 416/2972 | 816/4182 | 414/2495 | 239/826 | 406/1798 | 440/1239 |
| Positivity | 14.0 | 19.5 | 16.6 | 28.9 | 22.6 | 35.5 | |
| 95% CI | (12.8 to 15.3) | (18.3 to 20.7) | (15.2 to 18.1) | (25.9 to 32.1) | (20.7 to 24.6) | (32.9 to 38.2) | |
| Coinfection | n/N | 47/2972 | 90/4182 | 57/2495 | 35/826 | 56/1798 | 88/1239 |
| Positivity | 1.6 | 2.2 | 2.3 | 4.2 | 3.1 | 7.1 | |
| 95% CI | (1.2 to 2.1) | (1.8 to 2.6) | (1.8 to 2.9) | (3.1 to 5.8) | (2.4 to 4.0) | (5.8 to 8.7) | |
| Chlamydia† | n/N | 212/2970 | 392/4181 | 224/2489 | 105/825 | 192/1798 | 193/1239 |
| Positivity | 7.1 | 9.4 | 9.0 | 12.7 | 10.7 | 15.6 | |
| 95% CI | (6.3 to 8.1) | (8.5 to 10.3) | (7.9 to 10.2) | (10.6 to 15.2) | (9.3 to 12.2) | (13.7 to 17.7) | |
| Urogenital | n/N | 92/2959 | 149/4178 | 88/2484 | 28/824 | 58/1792 | 64/1238 |
| Positivity | 3.1 | 3.6 | 3.5 | 3.4 | 3.2 | 5.2 | |
| 95% CI | (2.5 to 3.8) | (3.0 to 4.2) | (2.9 to 4.3) | (2.4 to 4.9) | (2.5 to 4.2) | (4.1 to 6.5) | |
| Anal | n/N | 150/2781 | 275/4011 | 149/2407 | 83/819 | 139/1787 | 144/1234 |
| Positivity | 4.3 | 6.5 | 6.2 | 12.0 | 7.8 | 11.7 | |
| 95% CI | (3.6 to 5.1) | (5.8 to 7.3) | (5.3 to 7.2) | (9.9 to 14.4) | (6.6 to 9.1) | (10.0 to 13.6) | |
| Oral | n/N | 17/2618 | 44/3678 | 23/2250 | 9/758 | 35/1685 | 22/1195 |
| Positivity | 0.6 | 1.2 | 1.0 | 1.2 | 2.1 | 1.8 | |
| 95% CI | (0.4 to 1.0) | (0.9 to 1.6) | (0.7 to 1.5) | (0.6 to 2.2) | (1.5 to 2.9) | (1.2 to 2.8) | |
| Gonorrhoea† | n/N | 194/2970 | 405/4180 | 194/2489 | 125/826 | 211/1798 | 269/1239 |
| Positivity | 6.5 | 9.7 | 7.8 | 15.1 | 11.7 | 21.7 | |
| 95% CI | (5.7 to 7.5) | (8.8 to 10.6) | (6.8 to 8.9) | (12.9 to 17.7) | (10.3 to 13.3) | (19.5 to 24.1) | |
| Urogenital | n/N | 53/2961 | 103/4178 | 66/2484 | 39/825 | 49/1795 | 57/1237 |
| Positivity | 1.8 | 2.5 | 2.7 | 4.7 | 2.7 | 4.6 | |
| 95% CI | (1.4 to 2.3) | (2.0 to 3.0) | (2.1 to 3.4) | (3.5 to 6.4) | (2.1 to 3.6) | (3.6 to 5.9) | |
| Anal | n/N | 118/2775 | 262/4009 | 124/2407 | 98/820 | 129/1786 | 203/1236 |
| Positivity | 4.3 | 6.5 | 5.2 | 12.0 | 7.2 | 16.4 | |
| 95% CI | (3.6 to 5.1) | (5.8 to 7.3) | (4.3 to 6.1) | (9.9 to 14.4) | (6.1 to 8.5) | (14.5 to 18.6) | |
| Oral | n/N | 104/2870 | 224/4122 | 99/2450 | 42/822 | 108/1793 | 126/1237 |
| Positivity | 3.6 | 5.4 | 4.0 | 5.1 | 6.0 | 10.2 | |
| 95% CI | (3.0 to 4.4) | (4.8 to 6.2) | (3.3 to 4.9) | (3.8 to 6.8) | (5.0 to 7.2) | (8.6 to 12.0) | |
| Syphilis | n/N | 45/2952 | 87/4166 | 33/2488 | 47/821 | 45/1798 | 63/1228 |
| Positivity | 1.5 | 2.1 | 1.3 | 5.7 | 2.5 | 5.1 | |
| 95% CI | (1.1 to 2.0) | (1.7 to 2.6) | (0.9 to 1.9) | (4.3 to 7.5) | (1.9 to 3.3) | (4.0 to 6.5) | |
| HIV | n/N | 15/2877 | 30/4068 | 28/2466 | 0/51 | 15/1760 | 6/625 |
| Positivity | 0.5 | 0.7 | 1.1 | 0.0 | 0.9 | 1.0 | |
| 95% CI | (0.3 to 0.9) | (0.5 to 1.1) | (0.8 to 1.6) | (0.0 to 7.0) | (0.5 to 1.4) | (0.4 to 2.1) | |
| LGV‡ | n/N | 3/130 | 10/253 | 5/140 | 24/78 | 8/135 | 26/135 |
| Positivity | 2.3 | 4.0 | 3.6 | 30.8 | 5.9 | 19.3 | |
| 95% CI | (0.8 to 6.6) | (2.2 to 7.1) | (1.5 to 8.1) | (21.6 to 41.7) | (3.0 to 11.3) | (13.5 to 26.7) | |
*Positivity calculated by number of MSM with a positive test divided by the total number of MSM tested.
†Positive at any location (urogenital, anal and/or oral).
‡LGV was tested only in rectal chlamydia-positive MSM.
CSH, centres for sexual health; LGV, lymphogranuloma venereum; MSM, men who have sex with men; MSP, multiple sex partners.