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1.
Tissue Antigens ; 64(3): 251-6, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15304005

ABSTRACT

Antigen-induced cellular immunogenicity may vary between populations due to differences in human leukocyte antigen (HLA) diversity and, hence, may play a critical role in the protection afforded by vaccines. In the setting of two, phase I/II human immunodeficiency virus-1 vaccine trials of a recombinant canarypox prime, and boosting with either recombinant monomeric gp120 or oligomeric gp160, we assessed the association between specific human leukocyte antigen (HLA) class I serotypes and the presence of cytotoxic T-lymphocyte response measured by 51Cr-release assay. HLA class I serotypes A11, A24, A33, B46, and B75 were the most common, present in 10% or more of 245 individuals studied. Forty of 187 (21.4%) Thai adults who received either ALVAC-HIV with gp120 or oligomeric gp160 or ALVAC alone had a precursor cytolytic CD8 T-cell response (pCTL). HLA-B44 was positively and significantly associated with a pCTL response (odds ratio 7.6, 95% CI: 2.7-21.2), whereas B46 was negatively associated but not robust when adjusted for multiple comparisons. Responses to Env proteins accounted for the majority (nine of 11) of pCTL activity among those persons with B44. This HLA class I serotype occurred in 9.4% of participants overall (including the placebo group), less commonly than what is reported from populations of European ancestry. These results strengthen the importance of assessing HLA class I distributions in conjunction with studies of vaccines designed to elicit cellular immunity in different populations.


Subject(s)
HIV Infections/prevention & control , HIV-1/immunology , Histocompatibility Antigens Class I/immunology , T-Lymphocytes, Cytotoxic/immunology , Viral Vaccines/administration & dosage , Adult , Female , HIV Envelope Protein gp120/immunology , HIV Envelope Protein gp160/immunology , HIV Infections/immunology , Humans , Male , T-Lymphocytes, Cytotoxic/virology , Thailand , Viral Vaccines/immunology
2.
AIDS ; 15(12): 1569-74, 2001 Aug 17.
Article in English | MEDLINE | ID: mdl-11504990

ABSTRACT

OBJECTIVE: To monitor HIV-1 infection trends among United States Army personnel, a predominantly young population group, tested between 1985 and 1999 for HIV-1 infection. DESIGN: Demographic correlates of HIV-1 infection were assessed in the cohort via epidemiologic analysis. METHODS: Annual seroconversion incidence rates were calculated per 1000 person-years (PY) of follow-up. Poisson regression was used to assess demographic correlates of HIV-1 seroconversion risk. RESULTS: There were 1275 seroconverters among 2 004 903 active duty Army personnel accounting for 7 700 231 PY of follow-up. The HIV-1 incidence rate (IR) was 0.17/1000 PY [95% confidence interval (CI), 0.16-0.17]. The highest IR was observed in the first year of testing (IR, 0.43/1000 PY; 95% CI, 0.33-0.52). The IR for male and female soldiers was 0.18/1000 PY and 0.08/1000 PY, respectively. HIV-1 incidence declined with age. Significant risk of HIV-1 seroconversion was associated with age [> 30 years old relative risk (RR), 1.51], race (Black RR, 4.61; Hispanic RR, 2.76), gender (male RR, 3.12), marital status (unmarried RR, 2.01) and rank (enlisted RR, 2.50). CONCLUSIONS: HIV-1 seroconversions in the US Army have been low and stable since the early 1990s. Continued HIV-1 incidence surveillance in the US Army provides information on the status of the epidemic in the Army, as well as important corroborative data on HIV-1 infections throughout the US.


Subject(s)
HIV Infections/epidemiology , HIV Seroprevalence , HIV-1 , Military Personnel , Adult , Female , HIV Infections/virology , Humans , Incidence , Male , Risk Factors , United States/epidemiology
3.
Mil Med ; 166(7): 571-6, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11469026

ABSTRACT

Systems for the staging of individuals with human immunodeficiency virus type 1 (HIV-1) infection were developed 15 years ago. Subsequently, assays for quantitating HIV-1 RNA and immunophenotyping of lymphocyte subsets have been developed and validated. The utility of these assays for improved staging in early disease was evaluated in 256 HIV-infected adults (52% minority) with CD4 counts > or = 400 cells/microL followed in U.S. military medical centers before the highly active anti-retroviral therapy era. HIV viral load (RNA) was quantitated; the frequencies of select CD4+ immunophenotypes were determined in 112 subjects. The results were analyzed in relation to three outcome measures: death, first acquired immunodeficiency syndrome-defining opportunistic infection, and CD4 count < or = 200 cells/microL. Serum RNA level and CD4 count were each found to be predictive of all three outcomes. In addition, increases in the T-cell subsets CD28-CD4+ and CD29+CD26-CD4+ were found to be independently predictive of more rapid progression. The classification of early-stage HIV patients is improved by the quantitation of both viral RNA and T-lymphocyte subsets.


Subject(s)
HIV Infections/immunology , HIV-1 , RNA, Viral/blood , T-Lymphocyte Subsets , Adult , Chi-Square Distribution , Disease Progression , Female , Humans , Lymphocyte Count , Male , Outcome Assessment, Health Care , Prognosis , Proportional Hazards Models , Statistics, Nonparametric , Survival Analysis
4.
AIDS Res Hum Retroviruses ; 16(11): 1061-6, 2000 Jul 20.
Article in English | MEDLINE | ID: mdl-10933621

ABSTRACT

Innate immunity may play a role in preventing HIV infection and progression to AIDS. Most studies of natural killer (NK) cell function have been conducted in populations with different HLA allele frequencies and HIV subtypes than those found in Southeast Asia. NK cell number and function, defined as CD3- cells expressing CD16+/CD56+ and the ability to lyse K562 cells, were enumerated in 42 HIV-seronegative Thais and 20 HIV-seronegative North Americans. The number and percentage of NK cells were similar for both groups, but cytotoxicity function expressed as lytic units (LU20) of NK cells was significantly greater in the Thai subjects compared with the North American subjects (p = 0.004). Comparisons were also conducted between the HIV-seronegative groups and HIV-infected subjects from both Thailand and North America. NK cell number and function were not significantly different between the Thai HIV-seronegative and -seropositive groups. However, the comparison between the North American HIV-seronegative and -seropositive subjects demonstrated profound impairment of NK cell number, percentage, and function (p < 0.001). Matching the Thai and North American HIV-infected subjects on CD4+ cell count revealed higher NK number and function in the Thai subjects (p < 0.001). The study indicates that NK function in both HIV-seronegative and -seropositive Thais is elevated relative to similar groups in North America.


Subject(s)
Asian People , HIV Infections/immunology , HIV-1/immunology , Killer Cells, Natural/immunology , White People , Cytotoxicity, Immunologic , Female , HIV Infections/ethnology , HIV-1/classification , Humans , Immunophenotyping , Lymphocyte Count , Male , North America , Thailand
5.
AIDS Res Hum Retroviruses ; 16(8): 801-5, 2000 May 20.
Article in English | MEDLINE | ID: mdl-10826486

ABSTRACT

The envelope-coding sequence of human immunodeficiency virus type 1 (HIV-1) was determined for 11 Thai seroconverters between 1995 and 1996. On the basis of the env sequences, all subjects were infected with HIV subtype E. Compared with the interpatient protein diversity among HIV-1 Thai reference sequences from 1990 to 1992 (4.4%), the diversity among the 1995-1996 seroconverters was approximately double (9.5%). The tetrapeptide tip of the V3 loop was invariant for 10 of the 11 seroconverters, and identical to that observed in sequences derived from the 1990-1992 group. However, in the V3 region, sequences from 2 of the 11 subjects demonstrated more than 5 amino acid changes relative to the reference strains. This may represent the "aging" of the HIV epidemic seen in other endemic regions. These findings may have substantial implications for vaccine development and evaluation for both HIV antibody and cytotoxic T lymphocyte repertoire recognition.


Subject(s)
Genetic Variation , HIV Antibodies/blood , HIV Envelope Protein gp120/genetics , HIV Infections/virology , HIV-1/genetics , Peptide Fragments/genetics , Adult , Amino Acid Sequence , Female , HIV Envelope Protein gp120/chemistry , HIV Envelope Protein gp160/chemistry , HIV Envelope Protein gp160/genetics , Humans , Male , Molecular Sequence Data , Peptide Fragments/chemistry , Phylogeny , Sequence Analysis, DNA , Thailand
6.
Vaccine ; 18(15): 1448-55, 2000 Feb 14.
Article in English | MEDLINE | ID: mdl-10618542

ABSTRACT

Fifty-two human immunodeficiency virus type 1, seronegative Thai adults from the community were enrolled in a double-blind, placebo controlled, phase I/II trial of HIV SF2 gp120/MF59 vaccine to determine the safety and immunogenicity of this recombinant, B clade, HIV envelope protein vaccine. Twenty-six subjects were enrolled at each of two sites in Thailand, Bangkok and Chiang Mai. Twelve subjects received placebo and 40 subjects received vaccine (50 microg). Subjects were immunized according to one of two schedules, 0, 1 and 4 or 0, 1 and 6 months. The frequency of adverse reactions was not different between placebo and vaccine subjects, nor between immunization schedules. Of vaccinees, all developed high-titer binding antibody to the immunogen (rgp120), 39 developed neutralizing antibody (NA) responses against homologous virus (HIV-1(SF2)), and 22 developed NA against heterologous virus (HIV-1(MN)). No subject demonstrated intercurrent HIV infection, however screening EIA reactivity occurred in 27% of recipients. Thus, this candidate HIV vaccine was found to be safe and immunogenic in Thai adults, laying the foundation for development of a subtype E construct in this population.


Subject(s)
AIDS Vaccines/immunology , HIV Envelope Protein gp120/immunology , Vaccines, Synthetic/immunology , Adult , Double-Blind Method , Female , Follow-Up Studies , HIV Antibodies/blood , HIV Seronegativity , Humans , Lymphocyte Activation , Male , Middle Aged , Thailand
7.
J Acquir Immune Defic Syndr Hum Retrovirol ; 20(3): 308-14, 1999 Mar 01.
Article in English | MEDLINE | ID: mdl-10077182

ABSTRACT

Behavioral and social issues were investigated in phase I/II preventive HIV vaccine trial volunteers in Thailand. These included risk behavior, HIV knowledge, distress, and social experiences associated with trial participation. Data were collected at baseline and at 4- and 8-month follow-up visits. Volunteers reported relatively low levels of risk behaviors at baseline and at the follow-up visits. About one fifth reported overtly negative reactions from family or friends. No problems with discrimination in employment, health care, or insurance were reported. Findings add to the evidence suggesting the feasibility of phase I/II prophylactic HIV vaccine trials with low-risk volunteers in Thailand.


Subject(s)
AIDS Vaccines , HIV Infections/prevention & control , Risk-Taking , Vaccines, Synthetic , Volunteers/psychology , Adult , Double-Blind Method , Evaluation Studies as Topic , Female , Follow-Up Studies , Health Knowledge, Attitudes, Practice , Humans , Life Style , Male , Middle Aged , Thailand
8.
Nat Med ; 4(7): 746, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9662343
9.
Article in English | MEDLINE | ID: mdl-9886132

ABSTRACT

The pandemic of HIV/AIDS consists of multiple foci with distinct epidemiological characteristics. Among the approximately one million Southeast Asians infected with HIV, subtype (clade) E infections predominate. This subtype, a recombinant virus comprised of a clade A core (gag) gene and a mosaic clade A/clade E envelope (env) gene, became broadly epidemic in Thailand beginning in 1989. Since then, subtype E HIV has become increasingly prevalent throughout Southeast Asia. Consistent with the recent introduction of clade E HIV, the diversity of Southeast Asian subtype E viruses is narrow (6% nucleotide diversity across env). Since neutralizing antibodies may play a protective role against HIV infection, and are relatively clade specific for genotype E viruses, a subtype E-derived candidate vaccine tested in Southeast Asia would provide an optimal test of vaccine concept. It would also provide, for the first time to a developing region of the world, a non-B clade candidate vaccine designed specifically for the local epidemic. A consortium of industry (Chiron Vaccines and Pasteur Merieux Connaught), academic (Mahidol and Chiang Mai Universities) and military (United States and Royal Thai Army Medical Departments) medicine is working together to develop and test HIV vaccines for the genotype E epidemic. A genotype B recombinant glycoprotein (rgp)120 candidate vaccine has undergone phase I/II testing in Thailand and confirmed to be safe and immunogenic in this ethnic group. An rgp120 (E) has been produced and a phase I/II trial of the bivalent product (B/E) is in the final stages of approval. This vaccine construct is designed to elicit humoral immune responses. To augment these antibody responses with CD8+ CTL responses, an E-specific, live-vectored vaccine is being developed which will be used in conjunction with rgp120 in a second vaccine approach. Canarypox (ALVAC) constructs containing multiple HIV genes (gag/pol/env) currently designed for the subtype B epidemics will be modified to contain a clade E env gene sequence. After predetermined milestones have been met, these two subtype E-specific candidate vaccines will be assessed for protection in a large collaborative efficacy trial. Since neither animal models nor laboratory assays are validated as predictive of HIV vaccine efficacy, it must be through such a phase III trial that vaccine-induced protection and immunologic correlates will be determined.


Subject(s)
AIDS Vaccines , HIV Infections/prevention & control , HIV/classification , Asia, Southeastern , HIV/immunology , Humans
10.
JAMA ; 276(21): 1743-6, 1996 Dec 04.
Article in English | MEDLINE | ID: mdl-8940323

ABSTRACT

OBJECTIVE: To examine the risk of suicide among individuals positive for the human immunodeficiency virus (HIV) following screening for evidence of HIV infection. Prior studies have reported a 7- to 36-fold increased risk of suicide for persons with the acquired immunodeficiency syndrome. DESIGN: Prospective cohort study. SETTING: Military service applicants from throughout the United States. MAIN OUTCOME MEASURE: Death from suicide. METHODS: The National Death Index was searched for mortality among 4147 HIV-positive military service applicants and 12437 HIV-negative applicants disqualified from military service due to other medical conditions (matched 1:3 on age, race, sex, and screening date and location) identified by the US Department of Defense between October 1985 and December 1993. Death certificates were obtained from individual states. Identifiers and HIV status of living applicants were known only by the Department of Defense. RESULTS: The HIV-positive applicants were 92% male, 37% white, and 56% black. Median age was 24 years (range, 17-57 years). Median follow-up time was 70 months (range, 0-99 months). Ten HIV-positive (49 per 100 000 person-years) and 24 HIV-negative applicants (36 per 100 000 person-years) died of suicide (rate ratio [RR], 1.35; 95% confidence interval [CI]= 0.58-2.93). Suicide rates among both HIV-positive (RR, 2.08; 95% CI, 1.00-3.82) and HIV-negative (RR, 1.67; 95% CI, 1.07-2.48) applicants are marginally higher than those for the US general population, after adjustment for age, race, and sex. Time from screening to death was less than 3 months for 3 of 10 HIV-positive and 2 of 24 HIV-negative applicants who died of suicide. CONCLUSIONS: The HIV-positive individuals do not appear to have a significantly increased risk of death from suicide in the months following HIV screening in this study population. Because suicide risk is reported to be greatly increased after symptomatic HIV disease is present, clinicians should consider asking persons with HIV infection about suicide risk factors during both initial counseling and subsequent medical care.


Subject(s)
HIV Infections/psychology , Suicide/statistics & numerical data , AIDS Serodiagnosis , Adolescent , Adult , Cohort Studies , Female , HIV Infections/mortality , HIV Infections/prevention & control , Humans , Incidence , Male , Mass Screening , Middle Aged , Prospective Studies , Risk , United States
11.
AIDS Res Hum Retroviruses ; 12(14): 1319-28, 1996 Sep 20.
Article in English | MEDLINE | ID: mdl-8891111

ABSTRACT

Classification of human immunodeficiency virus type 1 (HIV-1) by neutralization serotype may be important for the design of active and passive immunization strategies. Neutralizing antibody serotyping is hindered by the lack of standard reagents and assay format, and by the weak activity of many individual sera. To facilitate cross-clade neutralization analysis, we used an infectivity reduction assay (IRA) and selected clade-specific serum (or plasma) pools from subjects infected with clade B and E HIV-1, respectively. Several serum pools were utilized; some were selected for strong neutralizing activity against intraclade viruses and others were derived from conveniently available samples. Against a panel of 51 clade B and E viruses, serum pools displayed strong neutralization of most intraclade viruses and significantly diminished cross-clade neutralization. Results were confirmed against a blinded panel of 20 viruses. The data indicate that the phylogenetic classification of virus subtypes B and E corresponds to two distinct neutralization serotypes. This approach to neutralizing antibody serotyping may be useful in defining the antigenic relationship among viruses from other clades.


Subject(s)
HIV Seropositivity/diagnosis , Serotyping/methods , Enzyme-Linked Immunosorbent Assay , HIV Envelope Protein gp120/metabolism , HIV Envelope Protein gp160/metabolism , Humans , Neutralization Tests , Peptide Fragments/metabolism
12.
J Virol ; 70(6): 3331-8, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8648662

ABSTRACT

Human immunodeficiency virus type 1 isolates of clade E, known to be largely responsible for the fulminating epidemic in Southeast Asia, have been derived exclusively from Asia and Africa. Here we provide full or partial sequences of the envelope glycoprotein gene from 13 additional clade E isolates from Asia representing patients in both early and late stages of disease. More extensive comparison of isolates within clade E by geographic locale, stage of disease, and year of isolation is now possible. The genetic diversity of clade E isolates from Asia, particularly among those derived from early-stage patients, is restricted compared with African isolates (mean interisolate distances in gp120, 5.4 and 20.2%, respectively). However, patients hospitalized with AIDS-related illnesses in Thailand harbored clade E isolates exhibiting broader interisolate diversity and with highly heterogeneous third hypervariable loop sequences. An additional pair of cysteine residues, predicting a novel disulfide bridge and present in 80% of clade E isolates from Asia, was uniformly absent from six African isolates. Clade E isolates in Thailand from early-stage subjects continue to be genetically similar to potential vaccine prototype strains, providing a favorable environment for the evaluation of genotype E candidate vaccines. However, evidence of increasing interisolate diversity is appearing among late-stage patients in Asia. This diversification of the clade E virus, if sustained, may impact preventive vaccine development strategies.


Subject(s)
HIV-1/chemistry , Viral Envelope Proteins/chemistry , Africa , Amino Acid Sequence , Asia , CD4 Antigens/metabolism , HIV Envelope Protein gp120/chemistry , HIV Envelope Protein gp41/chemistry , Humans , Molecular Sequence Data
13.
Article in English | MEDLINE | ID: mdl-8605595

ABSTRACT

Geographic and demographic correlates of risk for HIV-1 seropositivity were studied in 120,216 young men selected by lottery for service in the Royal Thai Army (RTA). The study population consisted of men selected between November 1991 and May 1993. Venous blood was collected at induction, and a brief demographic questionnaire was administered. HIV-1 seropositivity was established by Western blot confirmation of duplicate reactive ELISAs. Geographic variable provided the strongest correlate of risk, clearly distinguishing residents of the upper north, Bangkok, and the central region from the northeast. Overall 12.2% of men from the upper north were HIV-positive. Men who had lived in rural areas were at less risk in most regions of the country, but had equal risk in the upper north. Unmarried men and those with less education were at higher risk throughout the country. These data provide valuable information on the prevalence of HIV infection in one segment of the general population. Continued surveillance of this group will facilitate evaluation of Thailand's response to the epidemic.


PIP: During November 1991 to May 1993, interviews were conducted with and blood samples drawn from 120,216 male military recruits aged 21-29 of the Royal Thai Army (RTA) from every geographic region and social stratum of Thailand. 93.5% were 21 years old. These men are somewhat more representative of the general population than the traditional high risk groups since selection for military service is by lottery and includes all regions of Thailand. The overall HIV seroprevalence was 3.5%. Men from the Upper North region had the highest HIV seroprevalence rate (12.2% vs. 2-4%). This region encompassed the following provinces: Phayao, Chiang Rai, Chiang Mai, Lamphun, Lampang, Phrae, Nan, and Mae Hong Sun. The multivariate analysis of the 97,848 men with a complete set of demographic data and confirmed serostatus (83% of all men inducted) revealed that region of residence was a significant predictor of HIV infection. The odds ratio (OR) of HIV infection among men in the Upper North region was 7.83 (p 0.01). In every region of the country except Upper North, the risk of HIV infection was higher for men from urban areas than those from rural areas (OR = 1.37). In the Upper North region, rural residents were more likely to have HIV infection than urban residents. The higher the man's educational status, the less likely he was to have HIV infection (OR = 0.31 for 13-16 years of education; p 0.01). Risk of HIV infection attributable to age was only significant in unmarried men (OR = 1.76; p 0.01). Thailand has already introduced extensive AIDS education and prevention efforts; they should continue.


Subject(s)
HIV Seropositivity/epidemiology , HIV-1/immunology , Military Personnel , Adult , Analysis of Variance , Cohort Studies , Educational Status , HIV Antibodies/blood , Humans , Male , Marital Status , Multivariate Analysis , Prevalence , Risk Factors , Rural Population , Surveys and Questionnaires , Thailand/epidemiology , Urban Population
14.
J Infect Dis ; 173(2): 340-8, 1996 Feb.
Article in English | MEDLINE | ID: mdl-8568294

ABSTRACT

Phase I studies of volunteers not infected with human immunodeficiency virus type 1 (HIV-1) have shown that immunization with envelope subunit vaccine products elicits antibodies that neutralize laboratory-adapted (prototype) HIV-1 strains in vitro. Prototype strains are adapted to grow in continuous (neoplastic) cell lines and are more susceptible to neutralization than are primary isolates cultured in human peripheral blood mononuclear cells. In this study, 50 sera from nine phase I vaccine trials and 16 from HIV-1-infected persons were evaluated for neutralizing antibody activity against 3 laboratory-adapted and 5 primary HIV-1 isolates. Of 50 sera, 49 neutralized at least 1 of the prototype strains; however, none displayed neutralizing activity against primary isolates of HIV-1. Serum from most HIV-1-infected persons neutralized both laboratory-adapted and primary HIV-1 isolates. These data demonstrate a qualitative, or large quantitative, difference in the neutralizing antibody response induced by envelope subunit vaccination and natural HIV-1 infection.


Subject(s)
AIDS Vaccines/administration & dosage , Gene Products, env/immunology , HIV Antibodies/immunology , HIV Envelope Protein gp120/immunology , HIV Infections/immunology , HIV-1/immunology , Immunization , Protein Precursors/immunology , Adolescent , Adult , Cells, Cultured , Double-Blind Method , Female , HIV Envelope Protein gp160 , HIV Infections/virology , HIV-1/isolation & purification , Humans , Leukocytes, Mononuclear/virology , Male , Middle Aged , Neutralization Tests , Virus Cultivation
16.
Am J Public Health ; 85(11): 1500-6, 1995 Nov.
Article in English | MEDLINE | ID: mdl-7485661

ABSTRACT

OBJECTIVES: This study sought to examine risk factors associated with human immunodeficiency virus type 1 (HIV-1) seroconversion among active-duty men in the US Army. METHODS: One hundred twenty-eight men with documented HIV-1 seroconversion between 1988 and 1991 were matched to control subjects on demographic variables. Risk factor information was collected for the seroconversion period. RESULTS: Forty-nine case subjects and no control subjects reported same-gender sex; this includes 34 case subjects who also reported sex with women. Seventy case and 118 control subjects reported no risk factors other than heterosexual intercourse. Among heterosexuals, excess risk was noted for men who had sex with women in risk categories defined by the Centers for Disease Control and Prevention (odds ratio = 10.0; 95% confidence interval = 1.3, 78.1). Significant trends of increasing risk for seroconversion were found with increasing numbers of female partners, nonsteady partners, and partners with whom sex occurred on the first day of acquaintance. CONCLUSIONS: In this population, the major risk factor for HIV-1 seroconversion was same-gender sex. Among heterosexuals, sex with anonymous or causal partners increased this risk. Intervention programs should emphasize the risk of indiscriminate partner selection in addition to "safe sex" practices.


Subject(s)
HIV Seropositivity/epidemiology , Military Personnel , Sexual Behavior/statistics & numerical data , Adult , Female , Humans , Male , Risk Factors , Sexual Partners , Sexually Transmitted Diseases/epidemiology , Surveys and Questionnaires , United States/epidemiology
17.
J Acquir Immune Defic Syndr Hum Retrovirol ; 10(2): 177-85, 1995 Oct 01.
Article in English | MEDLINE | ID: mdl-7552483

ABSTRACT

The direct measurement of the incidence of new infections with the human immunodeficiency virus type 1 (HIV-1) can be made among soldiers because of the routine and periodic nature of HIV-1 testing in the United States Army. Between November 1985 and October 1993, 978 HIV-1 seroconversions were seen among 1,061,768 soldiers, contributing over 3.6 million person-years of follow-up [seroconversion rate (95% confidence interval) = 0.27/1,000 person-years (0.25-0.29)]. A significant decreasing trend in HIV-1 seroconversion rates was seen over the analysis period. The rate of new infections declined significantly from the first interval, 1985-1987, (0.43/1,000 person-years) to the second interval, 1987-1988, (0.28/1,000 person-years), but stabilized at approximately 0.22/1,000 person-years after 1988, representing new infections in approximately 100-150 soldiers annually. The risk of seroconversion among active duty soldiers was significantly associated with racial/ethnic group, age, gender, and marital status. Surveillance of HIV-1 seroconversion rates in the U.S. Army continues to offer a unique opportunity to assess temporal trends in the evolving HIV-1 infection epidemic. Monitoring the rate of new HIV-1 infections allows for identification of subgroups in need of intervention, refocusing of intervention strategies, and evaluation of their effectiveness.


Subject(s)
HIV Infections/epidemiology , HIV Seropositivity/epidemiology , HIV-1 , Military Personnel , Adult , Age Distribution , Cohort Studies , Ethnicity , Female , Humans , Incidence , Male , Marital Status , Multivariate Analysis , Sex Distribution , Time Factors , United States/epidemiology
18.
AIDS ; 9(9): 1061-5, 1995 Sep.
Article in English | MEDLINE | ID: mdl-8527079

ABSTRACT

OBJECTIVE: To evaluate trends in HIV-1 seroprevalence in Thailand. DESIGN: HIV-1 serosurvey of successive cohorts of young Thai men entering service with the Royal Thai Army (RTA) between November 1989 and November 1994. METHODS: In November 1989, the RTA Medical Department began routine HIV-1-antibody screening of men who were selected by lottery for conscription. Between November 1989 and November 1994, 311,108 young men were screened at induction. Demographic data were collected between November 1991 and May 1993 and again in November 1994. RESULTS: The seroprevalence of HIV-1 among conscripts nationwide increased rapidly from 0.5% in 1989 to 3.5% in 1992 and reached 3.7% in 1993. In 1994, the overall prevalence decreased to 3.0%. The decrease was greatest in the upper North (from 12.4% in 1992 to 7.9% in 1994), where the prevalence has been the highest. However, decreases were observed in men from all regions of residence in the country, from both rural and urban areas, and at all educational levels. CONCLUSIONS: The decline in prevalence suggests declining incidence and that HIV control programs in Thailand are having an impact on the HIV epidemic.


PIP: Since 1989, the Royal Thai Army has screened new conscripts for human immunodeficiency virus (HIV)-1 infection. An analysis of HIV test results for the 311,108 young men entering the Army between November 1989 and November 1994 indicates that the Thailand Government's acquired immunodeficiency syndrome (AIDS) prevention program has had a positive impact on high-risk behaviors. The HIV seroprevalence increased from 0.5% in 1989 to 3.5% in 1992 and 3.7% in 1993, but then fell to 3.0% in 1994. The prevalence in the North--the region with the highest rate--peaked at 7.5% in 1992, then declined to 5.1% in 1994. This pattern of decline was observed in all regions of residence and at all educational levels. The only exception was a slight increase (from 4.1% in 1992 to 5.0% in 1994) in seroprevalence among the 4.2% of conscripts aged 22-29 years. Condom use, less frequent visits to commercial sex workers, and decreasing rates of sexually transmitted diseases are assumed to be the factors contributing to the decline in HIV infection.


Subject(s)
Developing Countries , HIV Infections/epidemiology , HIV Seroprevalence/trends , HIV-1 , Military Personnel/statistics & numerical data , Adult , Cohort Studies , HIV Infections/prevention & control , Humans , Incidence , Male , Rural Population/statistics & numerical data , Thailand/epidemiology , Urban Population/statistics & numerical data
19.
J Acquir Immune Defic Syndr (1988) ; 7(12): 1270-5, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7965638

ABSTRACT

Royal Thai Army (RTA) enlistees were tested for HIV-1 seropositivity prospectively in order to explore their feasibility as a cohort in an HIV-1 preventive vaccine efficacy trial. The 17,615 seronegative enlistees, virtually all 21-year-old men, contributed 10,409 person-years (p-y) of follow-up. Cohorts were enlisted in November 1991 and May 1992 from northern Thailand and Bangkok. The follow-up rate was 50%, with loss to follow-up significantly associated with location of the base, marital status, and educational level. Seroincidence was 0.5/100 p-y for recruits stationed in Bangkok, 1.0/100 p-y in the lower north, and 3.2/100 p-y in the upper north. In a multiple regression model, the young man's birthplace was strongly associated with risk of infection, suggesting that transmission occurred during leave as well as during duty. Incidence rates were significantly lower in those who were married at the time of enlistment and in those with > or = 10 years of education. The seroincidence rates among recruits stationed in the upper north support vaccine trial feasibility, but follow-up rates need to be improved.


Subject(s)
HIV Seropositivity/epidemiology , Military Personnel , Adult , Analysis of Variance , Cohort Studies , Follow-Up Studies , Humans , Incidence , Male , Multivariate Analysis , Poisson Distribution , Prospective Studies , Risk Factors , Socioeconomic Factors , Thailand/epidemiology
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