Global burden and trends of sexually transmitted infections from 1990 to 2019: an observational trend study.

Background: Sexually transmitted infections (STIs) are a major public health issue worldwide, but there is a paucity of literature on their burden and trends globally. We aimed to assess the global disease burden and trends of STIs from 1990 to 2019.

Methods: In this observational trend study, we collected data on incident cases, age-standardised incidence rate, and disability-adjusted life-years (DALYs), and calculated age-standardised DALY rates, for five STIs (syphilis, chlamydia, gonorrhoea, trichomonas, and genital herpes) between 1990 and 2019, by sex, geographical region, and cause using data exclusively from the Global Burden of Disease study 2019. The estimated annual percentage changes in the age-standardised incidence rate and age-standardised DALY rate were calculated to quantify the changing trend.

Findings: Globally, the age-standardised incidence rate of STIs showed a decreasing trend with an estimated annual percentage change of -0·04 (95% uncertainty interval [UI] -0·08 to 0·00) from 1990 to 2019, reaching 9535·71 per 100 000 person-years (8169·73 to 11 054·76) in 2019. The age-standardised DALY rate showed a decreasing trend with an estimated annual percentage change of -0·92 (-1·01 to -0·84) and reached 22·74 per 100 000 person-years (14·37 to 37·11) in 2019. The sub-Saharan African region had the highest age-standardised incidence rate (19 973·12 per 100 000 person-years, 17 382·69 to 23 001·57) and age-standardised DALY rate (389·32 per 100 000 person-years, 154·27 to 769·74). Adolescents had the highest incidence rate (18 377·82 per 100 000 person-years, 14 040·38 to 23 443·31) and showed stable total STI trends, except for an upward trend of syphilis between 2010 (347·65 per 100 000 person-years, 203·58 to 590·69) and 2019 (423·16 per 100 000 person-years, 235·70 to 659·01). Male individuals had a higher age-standardised incidence rate (10 471·63 per 100 000 person-years, 8892·20 to 12 176·10) than female individuals (8602·40 per 100 000 person-years, 7358·00 to 10001·18), whereas female individuals had a higher age-standardised DALY rate (33·31 per 100 000 person-years, 21·05 to 55·25) than male individuals (12·11 per 100 000 person-years, 7·63 to 18·93).

Interpretation: Although most countries showed a decrease in age-standardised rates of incidence and DALYs for STIs, the absolute incident cases and DALYs increased from 1990 to 2019. Therefore, STIs still represent a global public health challenge, especially in sub-Saharan Africa and Latin America, which warrants more attention and health prevention service.

Funding: Mega-Project of National Science and Technology for the 13th Five-Year Plan of China and the National Natural Science Foundation of China.