Transmitted drug resistance and subtype patterns of viruses from reported new HIV diagnoses in Germany, 2017-2020.

Background: The transmission of resistant HIV variants jeopardizes the effective use of antiretrovirals for therapy and prophylaxis. Molecular surveillance of new HIV diagnoses with a focus on prevalence and type of resistance associated mutations and the subtype of circulating viruses is mandatory.

Method: From 2017 to 2020, 11,527 new HIV diagnoses were reported in Germany to the Robert Koch Institute (RKI). Protease (PR) and reverse-transcriptase (RT) sequences were obtained from 4559 (39.6%) cases, and PR, RT and integrase (IN) sequences were obtained from 3097 (26.9%) cases. The sequences were analyzed with data from the national HIV reports.

Results: Among all cases in the analysis, the proportion of primary resistance was 4.3% for nucleoside reverse-transcriptase inhibitors (NRTIs), 9.2% for non-NRTI (NNRTIs), 3.3% for protease inhibitors (PIs) and 1.4% for integrase inhibitors (INIs). Dual-class resistance was highest for NRTIs/NNRTIs with 1.2%. There was no trend in the proportion of viruses resistant to drug classes. Most individual key mutations associated with relevant resistance had a prevalence below 1% including K65R (0.1%) and M184V (0.6%). A notable exception was K103NS, with a prevalence of 2.9% and a significant increase (p=0.024) during 2017-2020. In this period, diagnoses of infections with HIV-1 subtype B were the most common at 58.7%, but its prevalence was declining (p=0.049) while the frequency of minority subtypes (each < 1%) increased (p=0.007). Subtype B was highest (75.6%) in men who have sex with men (MSM) and lowest in reported heterosexual transmissions (HETs, 22.6%).

Conclusion: The percentage of primary resistance was high but at a stable level. A genotypic determination of resistance is therefore still required before the start of therapy. The subtype diversity of circulating HIV-1 is increasing.