[The characteristics of recent HIV-1 infection and associated factors in Tianjin].

The newly reported HIV infected cases was collected, and HIV blood samples were detected to identify recent HIV infection in Tianjin during 2008-2015. Factors associated with HIV-1 infection were analyzed by the univariate and multivariate unconditional logistic regression. The recent HIV-1 infection proportion of homosexuals increased from 37.70% in 2008 to 83.68% in 2015. Those cases who aged ≤30 years (OR=1.53, 95%CI: 1.30-1.79), in han ethnic group (OR=1.40, 95%CI: 1.02-1.91), students (OR=1.79, 95%CI: 1.28-2.51) were more likely to be recent infected. The cases who had a high school education (OR=1.28, 95%CI: 1.05-1.56) or collage education (OR=1.23, 95%CI: 1.00-1.50) were more likely to be recent infected than those who had a primary school education. Compared with patients identified by hospitals, the recent HIV infections were more likely to be found through voluntary counseling and testing (VCT), STD outpatients, men who have sex with men (MSM) investigation and unpaid blood donors. Homosexual transmission has become the major route of HIV-1 recent infection in Tianjin.

[Characteristics of baseline viral load before antiretroviral therapy in newly reported HIV-infected patients in Tianjin, 2019-2022].

Objective: To understand the baseline viral load (VL) of newly reported HIV- infected patients before antiretroviral therapy and related factors in Tianjin. Methods: Data were obtained from the China Disease Control and Prevention Information System, and the study subjects were HIV-infected patients before the first antiretroviral therapy in Tianjin from 2019 to 2022, and the information about their socio-demographic characteristics, baseline CD4+T lymphocyte (CD4) counts before antiretroviral therapy and baseline VL test results were collected, the baseline high VL was defined as ≥100 000 copies/ml. The effect of different factors on viral load were analyzed. Software SPSS 24.0 was used for statistical analysis. Results: A total of 1 296 newly reported HIV-infected patients were included in the study, in whom 15.89% (206/1 296) had high baseline VL, and multifactorial logistic regression analysis showed that those with history of STD (aOR=1.45, 95%CI:1.00-2.08) were more likely to have high baseline VL. Compared with those with baseline CD4 counts <200 cells/µl, those with baseline CD4 counts 200-350 cells/µl (aOR=0.40, 95%CI: 0.27-0.57), 351-500 cells/µl (aOR=0.32, 95%CI: 0.20-0.49), and >500 cells/µl (aOR=0.30, 95%CI: 0.18-0.49) were less likely to have high baseline VL. Conclusions: The proportion of HIV-infected patients with high baseline VL before antiretroviral therapy was low in Tianjin during 2019-2022. History of STD and baseline CD4 counts <200 cells/µl were associated with high baseline VL in HIV-infected patients, to which close attention needs to be paid in AIDS prevention and control.

[Transmitted drug resistance among HIV infected men who have sex with men in Tianjin, 2014-2017].

Objective: To understand prevalence and transmission of transmitted drug resistance (TDR) among HIV infected men who have sex with men (MSM) in Tianjin from 2014 to 2017. Methods: A total of 225 blood samples were collected from HIV infected MSM in Tianjin from 2014 to 2017. Pol gene fragments were obtained by viral RNA extraction and nested PCR amplification. Phylogenetic and drug resistance analyses were conducted. Results: A total of 205 samples were successfully sequenced and analyzed. Based on pol sequences, 53.2% (109/205), 28.8% (59/205), 10.2% (21/205), 4.9% (10/205) and 2.9% (6/205) of the samples were positive for HIV subtypes CRF01_AE, CRF07_BC, B, CRF55_01B and unique recombinant forms (URFs). Twenty transmission clusters, including 75 sequences, were identified and 62.5% (10/16) of sequences with TDR were in 5 clusters. The prevalence of TDR was 7.8% between 2014 and 2017. The annual prevalence rate increased from 3.9% (2/51) in 2014, 5.7% (3/53) in 2015, 9.6% (5/52) in 2016 to 12.2%(6/49) in 2017, the difference was not significant (χ(2)=2.504, P=0.127). CRF01_AE and B strains had high TDR prevalence (3.4%, 7/205) and (2.9%, 6/205), respectively. The TDR mutation was mainly NNRTIs, the TDR prevalence was 6.3% (13/205). In contract, the TDR prevalence of NRTIs and PIs were 1.5% (3/205) and 1.0% (2/205) respectively. Conclusion: Results from this study suggested that the prevalence of HIV-1 TDR strains in MSM was serious in Tianjin. It is necessary to take effective prevention and control measures.

[Evaluation on follow-up intervention program in men who have sex with men in Tianjin].

Objective: To evaluate the behavior intervention program on men who have sex with men (MSM) in Tianjin. Methods: From April 2013 to September 2017, MSM were enrolled from MSM gathering places and through mobile internet to establish an open prospective cohort. Interventions were conducted in every follow-up meeting, while the changes of behaviors and HIV infection and syphilis incidences in the MSM before and after intervention were compared. Results: A total of 1 822 MSM were interviewed at baseline survey, with 1 007 eligible MSM were enrolled in the cohort. A total of 39 new cases of HIV infection were reported, and the cumulative observation time on cohort follow-up was 2 216.96 person-year, with the HIV incidence rate as 1.76 per 100 person-years. Among them, 934 MSM were sero-negative for syphilis in baseline survey. A total of 100 new cases of syphilis were reported, and the cumulative observation time of cohort follow-up was 1 959.94 person-year, the syphilis incidence rate was 5.10 per 100 person-years. With health education and intervention conducted, the awareness rate of AIDS related knowledge for MSM increased. Though the rate of anal sex increased after intervention, the rate of condom use in anal sex increased, too. The rate of condom use decreased after receiving more than 3 interventions. Data from the multivariate GEE analysis indicated that protective factors might be as follows: education level of college and above (aOR=0.81, 95%CI: 0.68-0.98), awareness of AIDS related knowledge (aOR=0.52, 95%CI: 0.36-0.75), ever receiving condom promotion and distribution in the past six months (aOR=0.60, 95%CI: 0.49-0.74), being recruited from mobile internet (aOR=0.85, 95%CI: 0.73-1.00) and times of cumulative intervention: one time (aOR=0.55, 95%CI: 0.45-0.66), two times (aOR=0.38, 95%CI: 0.30-0.49), three times (aOR=0.26, 95%CI: 0.20-0.35), four times and above (aOR=0.24, 95%CI: 0.17-0.33). Diagnoses of STDs in the past six months (aOR=1.43, 95%CI: 1.06-1.96), using rush-poppers (aOR=1.22, 95%CI: 1.02-1.47) might be risk factors. Conclusions: After continuous behavior intervention, the incidence of HIV infection and syphilis were at a low level in the MSM cohort in Tianjin. Their awareness rate of AIDS related knowledge and the rate of condom use increased. But there are still many risk factors influencing the unprotected anal sex in MSM. We should continuously carry out behavioral intervention programs to prevent unprotected anal sex among MSM.

[Study on acute HIV-1 infection in men who have sex with men in Tianjin].

Objective: To understand the immunological and virological characteristics of HIV-1 infected men who have sex with men (MSM) in the acute phase in Tianjin and evaluate the effects of the fourth generation HIV ELISA and the P24 ELISA for acute HIV-1 infected samples. Methods: From October 2015 to October 2016, MSM were recruited through the community-based organizations in Tianjin. All the participants received rapid HIV test, positive samples were confirmed by Western Blot and negative samples underwent pooled nucleic acid testing. The participants with HIV-1 RNA reactive result underwent testing for viral load and T-cell count after second blood collection. Acute HIV-1 infection was defined as negative rapid HIV test result and the positive results of two HIV RNA tests, then the sensitivity were compared between the fourth generation HIV ELISA and the P24 ELISA to detect the initial HIV-1 RNA positive samples. Results: Among 3 016 MSM screened, 193 were positive in rapid HIV test. Western blot testing indicated that 179 cases were HIV positive, 7 cases were HIV indeterminate and 7 cases were negative. Of 2 823 sero-negative cases, 17 were acute HIV-1 infections. The HIV-1 infection rate was 6.53% (197/3 016) and the acute HIV-1 infection rate was 0.56% (17/3 016), with an average viral load of (5.63±1.50) log(10) copies/ml, an average CD(4) count of (442.82±268.17) cells/µl, an average CD(8) count of (1 069.65±668.22) cells/µl and an average CD(4)/CD(8) ratio of (0.49±0.25). Higher viral load, CD(4) and CD(4)/CD(8) ratio were seen in the acute HIV-1 infection group compared with the chronic HIV-1 infection group (U=148, P<0.01; U=272, P=0.042 and t=3.147, P=0.005). Demographic characteristics were similar between two groups, except the occupation (χ(2)=11.016, P=0.026). The sensitivity of P24 ELISA was higher than the fourth generation HIV ELISA in the HIV-1 detection for acute infection (Fisher's exact test, P=0.017). Conclusions: MSM are at risk for acute HIV-1 infection. Screening for acute HIV-1 infection with P24 ELISA would increase the sensitivity of diagnosis and reduce HIV transmission in MSM.

[Study of auxiliary diagnostic value of viral load test for samples with indeterminate HIV antibody detection results].

OBJECTIVE: To evaluate the auxiliary diagnostic value of viral load test for samples with indeterminate HIV antibody detection results. METHODS: Thirty-two samples with indeterminate HIV antibody detection results collected from MSM were used for two viral load tests in Tianjin in 2015. Follow up was conducted for this population to confirm their HIV infection status. RESULTS: Virus loads were detected in the 2 viral load tests. In the follow-up survey, the results of HIV antibody test of all the samples were positive. The results of viral load test were completely consistent with those of HIIV antibody confirmation test. CONCLUSION: The viral load test was effective in the auxiliary diagnosis of HIV infection in window phase, which can be used for the samples with indeterminate HIV antibody detection results.

[Molecular epidemiology and transmission of HIV in Tianjin, 2015].

OBJECTIVE: To understand the characteristics on the diversity of HIV subtypes and related transmission in Tianjin. METHODS: A total of 77 newly diagnosed ART-naïve HIV infectors in 2015 were screened by CD4(+) T cell counts ≥200 cells/µl. Viral RNAs were extracted from plasma samples. Reverse transcription PCR and nested PCR were used to analyze the amplification of pol and env gene fragments, sequencing, and related bioinformatics information. RESULTS: 46.03% (29/63), 30.16% (19/63), 11.11% (7/63), 4.76% (3/63) and 7.94% (5/63) of the individuals were infected under HIV subtypes CRF01_AE, CRF07_BC, B, CRF55_01B and URFs, with sexual transmission as the major mode of infection. CRF01_AE and CRF07_BC strains were predominant in both MSM and HST populations. The patterns of subtype distribution did not show statistical differences other than subtype B and CRF55_01B strain among HSTs. The proportion of CRFs increased significantly to 88.89%. 8 new second-generation recombinant forms were identified the first time, including 3 CRF55_01B, 2 AE/BC, 1 AE/B and 1AE/B/C among MSMs and 1 AE/BC among HSTs. 5.3% of the NNRTI L100I HIV infectors transmitted the drug-resistant-mutation strain. 3 linkages related to HIV transmission were confirmed through phylogenetic analysis with Bootstrap ≥98% of pol and ≥80% of env. CONCLUSION: The increasing complexity of HIV had been noticed in Tianjin, including the prevalence and transmission of second-generation recombinant and drug-resistant strains through different routes of transmission and in different regions.