Categorisation of the sexual behaviour of patients who had persistent C. trachomatis infections
| Category 1 | no sexual contact since initial diagnosis | 20 |
| Category 2 | protected sexual contact only | 4 |
| Categories 3 & 4 | unprotected sexual contact with a regular partner who had also tested positive and had been treated or a partner that did not test positive (cat 3) or unprotected oral sex only (cat 4) | 9 |
| Category 5 & Outliers | unprotected sexual contact with a partner of unknown history (cat 5) or patients with unknown sexual contact behaviour since initial diagnosis (outliers) | 6 |