Application of molecular epidemiology in revealing HIV-1 transmission network and recombination patterns in Tianjin, China.

Using a comprehensive molecular epidemiological approach, we characterized the transmission dynamics of HIV-1 among the MSM population in Tianjin, China. Our findings revealed that 38.56% (386/1001) of individuals clustered across 109 molecular transmission clusters (TCs), with MSM aged 50 and below being the group most commonly transmitting HIV-1. Among the identified TCs, CRF01_AE predominated, followed by CRF07_BC. Notably, CRF07_BC demonstrated a higher propensity for forming large clusters compared to CRF01_AE. Birth-death skyline analyses of the two largest clusters indicated that the HIV/AIDS transmission may be at a critical point, nearly all had Re approximately 1 by now. A retrospective analysis revealed that the rapid expansion of these large clusters was primarily driven by the introduction of viruses in 2021, highlighting the crucial importance of continuous molecular surveillance in identifying newly emerging high-risk transmission chains and adapting measures to address evolving epidemic dynamics. Furthermore, we detected the transmission of drug-resistant mutations (DRMs) within the TCs, particularly in the CRF07_BC clusters (K103N, Y181C, and K101E) and CRF01_AE clusters (P225H and K219R), emphasizing the importance of monitoring to support the continued efficacy of first-line therapies and pre-exposure prophylaxis (PrEP). Recombination analyses indicated that complex recombinant patterns, associated with increased amino acid variability, could confer adaptive traits to the viruses, potentially providing a competitive advantage in certain host populations or regions. Our study highlights the potential of integrating molecular epidemiological and phylodynamic approaches to inform targeted interventions.

The characteristics of recent HIV-1 infection and associated factors in Tianjin / 中华预防医学杂志

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.

Transmitted drug resistance among HIV infected men who have sex with men in Tianjin,2014-2017 / 中华流行病学杂志

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 CRF0 1_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 (x2=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 / 中华流行病学杂志

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 intemet 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 intemet (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.

Evaluation of a novel HIV-1 DNA reagent in clinical application / 中华实验和临床病毒学杂志

Objective@#To evaluate the clinical application of a novel HIV-1 DNA reagent.@*Methods@#HIV-1-infected and non-infected human blood samples were selected, as well as weakly positive samples, indeterminate samples, specific samples. Compared the result of HIV-1 DNA reagent with HIV-1 infection status (refer to the National Guideline for Detection of HIV/AIDS (2015)), the accuracy of the HIV-1 DNA reagent was evaluated in clinical application; Meanwhile, the commercially available RNA quantification kit was selected as reference reagent for parallel detection, and then the consistency and differences were evaluated between HIV-1 DNA reagent and RNA quantification reagent.@*Results@#A total of 95 whole blood samples were tested by the HIV-1 DNA reagent. Taking the HIV-1 infection status as the reference standard, the result showed that the positive agreement rate was 100% (95%CI: 93.94%-100%), the negative agreement rate was 100% (95%CI: 90.26%-100%), and the overall agreement rate was 100% (95%CI: 96.19%-100%). The Kappa value was 1 (95%CI: 1.00-1.00). The HIV-1 DNA reagent could detect weakly positive samples and indeterminate samples of early infection, and could effectively distinguish false-positive samples tested by the Ag-Ab reagent. The specific samples had no false-positive result .@*Conclusions@#The result of HIV-1 DNA reagent were consistent with the HIV-1 infection status. It can be considered as equivalent to the HIV-1 detection reagent commercially available in our country. It can effectively identify the indeterminate samples in the early infection. Compared with the RNA quantification reagent, it can effectively detect HIV-1 DNA of virus reservoirs.

Study on acute HIV-1 infection in men who have sex with men in Tianjin / 中华流行病学杂志

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 eases 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) log10 copies/ml,an average CD4 count of (442.82 ± 268.17) cells/μl,an average CD8 count of (1 069.65 ± 668.22) cells/μl and an average CD4/CD8 ratio of (0.49 ± 0.25).Higher viral load,CD4 and CD4/CD8 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 (x2=11.016,P=0.026).The sensitivity of P24 ELISA was higher than the fourth generation HIV ELISA in the H1V-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.

Transmitted drug resistance among HIV infected men who have sex with men in Tianjin, 2014-2017 / 中华流行病学杂志

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 / 中华流行病学杂志

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 / 中华流行病学杂志

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 / 中华流行病学杂志

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 / 中华流行病学杂志

Objective To understand the characteristics on the diversity of HIV subtypes and related transmission in Tianjin.Methods A total of 77 newly diagnosed ART-na(i)ve 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.

Study of auxiliary diagnostic value of viral load test for samples with indeterminate HIV antibody detection results / 中华流行病学杂志

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 / 中华流行病学杂志

Objective To understand the characteristics on the diversity of HIV subtypes and related transmission in Tianjin.Methods A total of 77 newly diagnosed ART-na(i)ve 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.

Normal Reference Values of Peripheral Blood CD4 and CD8 Lymphocytes for the Healthy Population in Tianjin / 中国慢性病预防与控制

Objective To establish the normal reference ranges of peripheral blood CD4 and CD8 lymphocytes for the healthy population in Tianjin. Methods 366 samples were recruited from among local physical examination adults and their absolute and proportional values for the ranges of CD4 and CD8 lymphocytes were detected by quantitative flow cytometry with fluorescence labeled antibodies. Results Mean absolute values were (860.27?255.15) cells/?l for CD4 T cells,(671.60?371.39) cells/?l for CD8 T cells and (1.44?0.62) for CD4/CD8 ratio; and the proportional values were (37.05?7.42)% for CD4 T cells,(28.42?7.46)% for CD8 T cells. Our results showed no differences between gender and age on CD4 T cell counts among the healthy adult population in Tianjin. Conclusions There is difference in CD4 T lymphocyte counts in different areas.