Lack of evidence for transmission of human immunodeficiency virus through vaginal intercourse

Research in determining risks for human immunodeficiency virus (HIV) transmission is confounded by many issues. They include lack of clarity or specificity in terminology used, respondents misunderstanding of questions, and lying. The base rate of lying (or social desirability responding) by itself is sufficient to account for the small percentage of Americans and Europeans claiming heterosexual transmission from partners not known to be intravenous drug users. This study integrates the physiological and epidemiological data on risk factors for HIV transmission with the psychological literature on the frequency of anal intercourse and of lying (in this case to researchers and clinicians about risk factors). When these factors are considered, intravenous and anal activities remain the only clear vectors for HIV transmission. Research suggesting that spermicidals are more effective at inactivating HIV than condoms are at physically containing HIV is also noted.     

Efficiency of human immunodeficiency virus transmission through injections and other medical procedures: evidence, estimates, and unfinished business.

OBJECTIVE: To estimate the transmission efficiency of human immunodeficiency virus (HIV) through medical injections and other invasive procedures. DESIGN: We searched our own files and Medline (from 1966-2004, using the keywords ["iatrogenic" or "nosocomial" or "injections"] and "HIV") for reports of iatrogenic outbreaks worldwide, except outbreaks traced to receipt of contaminated blood or blood products. We also analyzed information from a case-control study of percutaneous exposures to healthcare workers. SETTING: Worldwide healthcare settings. EVENTS: We identified 8 iatrogenic outbreaks that met our study criteria; published information from 4 outbreaks was sufficient to estimate transmission efficiency. RESULTS: From the 4 documented iatrogenic outbreaks, we estimated that 1 iatrogenic infection occurred after 8-52 procedures involving HIV-infected persons. Although only 0.3% of healthcare workers seroconvert after percutaneous exposure, a case-control study reported that deep injuries and other risk factors collectively increased seroconversion risk by as much as 50 times. Laboratory investigations demonstrate HIV survival through time and various rinsing regimens. We estimate that the transmission efficiency in medical settings with no or grossly insufficient efforts to clean equipment ranges from 0.5% to 3% for lower risk procedures (eg, intramuscular injections) and from 10% to 20% or more for high-risk procedures. Efforts to clean equipment, short of sterilization, may cut the transmission efficiency by 0%-100%. Procedures that contaminate multidose vials may accelerate transmission efficiency. CONCLUSION: To achieve better estimates of the transmission efficiency for a range of medical procedures and settings, investigations of iatrogenic outbreaks should be accorded high priority.     

Heterosexual transmission of human immunodeficiency virus.

Heterosexual human immunodeficiency virus (HIV) transmission accounts for most cases of HIV infection and acquired immunodeficiency syndrome worldwide. Moreover, in the developed world the proportion of individuals infected heterosexually is rising faster than the proportion infected by other routes, with an increase in the number of women infected. Defining the factors associated with heterosexual transmission may help control new infections.     

A school outbreak of Norwalk-like virus: evidence for airborne transmission

An outbreak of gastroenteritis affected a school attended by children aged 4-11 years. Epidemiological features suggested this was due to Norwalk-like virus (NLV) and this was confirmed by polymerase chain reaction (PCR). Nucleotide sequence analysis of the PCR amplicons revealed identical strains in all five positive stool samples. Pupils were significantly more likely to become ill following an episode of vomiting within their classroom (adjusted odds ratio 4.1, 95% CI 1.8-9.3). The times from exposure to illness were consistent with direct infection from aerosolized viral particles where exposure to vomiting was high. Cleaning with quaternary ammonium preparations made no impact on the course of the outbreak. However, the outbreak stopped after the school closed for 4 days and was cleaned using chlorine-based agents. This study confirms the importance of vomiting in the transmission of NLV and provides evidence that direct infection with aerosolized viral particles occurs.     

A review of statistical methods for estimating the risk of vertical human immunodeficiency virus transmission

BACKGROUND: Estimation of the risk of vertical transmission of human immunodeficiency virus (HIV) has been complicated by the lack of a reliable diagnostic test for paediatric HIV infection. METHODS: A literature search was conducted to identify all statistical methods that have been used to estimate HIV vertical transmission risk. Although the focus of this article is the analysis of birth cohort studies, ad hoc studies are also reviewed. CONCLUSIONS: The standard method for estimating HIV vertical transmission risk is biased and inefficient. Various alternative analytical approaches have been proposed but all involve simplifying assumptions and some are difficult to implement. However, early diagnosis/exclusion of infection is now possible because of improvements in polymerase chain reaction technology and complex estimation methods should no longer be required. The best way to analyse studies conducted in breastfeeding populations is still unclear and deserves attention in view of the many intervention studies being planned or conducted in developing countries.     

New epidemiological problem in Poland: vertical transmission of human immunodeficiency virus

New diagnostic, prophylactic and treatment perspectives in HIV infection of the fetus and newborn is a challenge for health services in Poland. In view of these advances, the ascertainment of HIV status of all pregnant women is important both for individuals and for the health services. By law, laboratory HIV testing in Poland can be performed only on a voluntary basis. All newly diagnosed cases of AIDS and HIV infections are anonymously reported to the National Institute of Hygiene in Warsaw. There are no clear data about vertical transmission of HIV infection in Poland mostly because of the unknown number of women who are positive at delivery. Almost all our data were collected from Polish Regional AIDS/HIV Diagnostic and Therapeutic Centres. During the period 1986–95, 88 children were delivered by HIV-positive women and vertical transmission occurred in 15 cases.     

Antiretroviral interventions to reduce mother-to-child transmission of human immunodeficiency virus: challenges for health systems, communities and society

This paper examines the ethical, economic and social issues that should be considered when antiretroviral interventions are being planned to reduce mother-to-child transmission of the human immunodeficiency virus. Interventions aiming to reduce mother-to-child transmission should be concerned with the rights of both the child and the mother. Women should not be seen as vectors of transmission but as people entitled to adequate health care and social services in their own right. For women accepting mother-to-child transmission interventions it is important to consider their medical and emotional needs and to ensure that they are not stigmatized or subjected to abuse or abandonment following voluntary counselling and testing. Seropositive women who do not wish to continue with pregnancy should have access to facilities for safe termination if this is legal in the country concerned. Problems arise in relation to the basic requirements for introducing such interventions via the health services in developing countries. A framework is given for making decisions about implementation of interventions in health care systems with limited resources where there is a relatively high prevalence of human immunodeficiency virus infection among pregnant women.     

外用杀微生物剂预防性传播疾病/艾滋病的可接受性研究进展

2007年联合国艾滋病规划署(UNAIDS)与世界卫生组织(WHO)估计,全世界HIV感染者中46.39%为女性[1].尽管采取了各种预防HIV/AIDS的措施,如使用安全套、减少性伴等,但HIV/AIDS的流行趋势并未减弱,特别是女性感染者数量逐年增加.     

Dogma disputed: potential endemic heterosexual transmission of human immunodeficiency virus in Australia

Abstract: The concept of tertiary sexual transmission of human immunodeficiency virus (HIV) has been central to government efforts to communicate notions of risk to heterosexuals in Australia. Data on heterosexually transmitted acquired immune deficiency syndrome (AIDS) and HIV for Australia are reviewed with emphasis given to the probability of misclassification bias in the heterosexually acquired and ‘other/undetermined’ categories. Tertiary cases are almost certainly rare in Australia, with little evidence of any increase in their incidence since the first cases were recorded. Three factors (low probability of exposure, the infectivity of HIV and a comparatively low rate of sexual partner change) make it improbable that Australian heterosexuals with no risk factors will experience endemic HIV infection, with a caveat to this conclusion lying in the potential of Australian sex tourism to Southeast Asia for introducing HIV into the Australian heterosexual population. Four hegemonic factors which have acted to suppress any serious debate of the notion that HIV in Australia is unlikely to become endemic among heterosexuals are discussed: the political ‘democratisation’ of risk inspired by concerns that gay men should not be further vilified as a victim group; the preventive imperative; a reluctance among health educators to question the very foundations of the message they are employed to deliver; and a reluctance to curtail ‘Trojan horse’ benefits to sexually transmissible disease prevention engendered by HIV education promoting safe sex messages.     

桥梁人群在艾滋病病毒传播中的作用

在艾滋病(AIDS)流行处在低流行期(本地任何类别高危人群的HIV感染率均低于5%)和聚集流行期(本地至少有一类高危人群的HIV感染率已达5%,总人群的HIV感染率<1%),AIDS流行主要集中在静脉吸毒者、暗娼、男男性接触者等高危人群中。随着AIDS流行形势的进展,HIV通过桥梁人群(如嫖客、流动人口等)进入到一般人群,或从一个人群传播到另一个人群,所危及人群的规模和组成是不同的,带来的危害大小不尽相同。HIV从高危人群进入到一般人群中,桥梁人群起着非常重要的作用。桥梁人群在HIV/AIDS传播中的作用愈来愈受到学术界和AIDS控制领     

构建口腔门诊控制人类免疫缺陷病毒传播标准化防范机制的研究

目的 构建一套切实可行、行之有效地控制口腔门诊传播人类免疫缺陷病毒(HIV)的标准规范.方法 首先对全国30名相关专家进行了3轮的问卷调查,建立了口腔门诊控制HIV传播标准规范;然后在湖北省12个市县的30所医院口腔门诊试行,并进行试行前后的评价对比.结果 试行后评价结果显著好于试行前;试行后9项细菌检测指标均达国家卫生标准,其合格率较试行前高,试行前后细菌菌落数的比较,差异均有统计学意义(P＜0.05);医护人员的防护意识增强、知识增加;管理人员的管理行为得分增高,与试行前比较,差异有统计学意义(P＜0.05).结论 通过研究制定的口腔门诊控制HIV传播的标准规范科学有效,值得推广.     

Heterosexual and homosexual transmission of hepatitis C virus: relation with hepatitis B virus and human immunodeficiency virus type 1.

A seroprevalence study was carried out on 1757 outpatients consecutively seen in a sexually transmitted disease (STD) clinic in order to evaluate the sexual transmission of hepatitis C virus (HCV). A total of 1442 consenting patients were tested for hepatitis C, hepatitis B and human immunodeficiency virus type 1 (HCV, HBV, HIV-1) antibodies. The relations between anti-HCV, anti-HBc and anti-HIV-1 were studied. Of 73 anti-HCV positive reactions, 45 (61.6%) were confirmed by the recombinant immunoblot assay (RIBA). The proportion of individuals with anti-HCV was higher in outpatients with a history of sexually transmitted disease than without. It was 2.8% in non drug user heterosexuals and 2.9% in non drug user homosexuals. Intravenous drug users (IDU) had higher anti-HCV prevalence when a history of STD was taken into account (42.3% in subjects with STD versus 36.7% in subjects without STD). Among non drug user heterosexuals an association was found between anti-HCV and anti-HBc. These data suggest that sexual transmission of HCV occurs, although it seems to be less efficient than other parenteral modes of transmission. When a more sensitive and specific marker of HCV infection become available, a more accurate estimate of the frequency and efficiency of the sexual transmission will be possible.     

Per-contact risk of human immunodeficiency virus transmission between male sexual partners.

The risk of human immunodeficiency virus (HIV) transmission from various types of homosexual contact, including oral sex, is of biologic, epidemiologic, and public health importance. The per-contact risk of acquiring HIV infection from specific acts was estimated in a prospective cohort study of 2,189 high-risk homosexual and bisexual men, conducted in San Francisco, California; Denver, Colorado; and Chicago, Illinois, in 1992-1994. During 2,633 person-years of follow-up, 60 seroconversions were observed. The estimated per-contact risk of acquiring HIV from unprotected receptive anal intercourse (URA) was 0.82 percent (95% confidence interval: 0.24, 2.76 percent) when the partner was known to be HIV+ and 0.27 percent (95% confidence interval: 0.06, 0.49 percent) when partners of unknown serostatus were included. There was heterogeneity in per-contact risk, with nine seroconversions occurring after only one or two episodes of URA. The per-contact risk associated with unprotected insertive anal and receptive oral sex with HIV-positive or unknown serostatus partners was 0.06 and 0.04 percent, respectively. URA accounted for only 15 percent of all reported sexual activity by seroconverters. As lower-risk practices become more common, they may play a larger role in propagating the epidemic and should also be addressed by interventions targeting high-risk homosexual and bisexual men.     

Hypothesis for the formation of human unresponsiveness to immunodeficiency virus

The paper reviews data on the genetics of various pathogens and the specific features of their host interactions. Particular emphasis is laid on human immunodeficiency virus (HIV-1), its origin theory, the time and site of its primary manifestations. The mechanism of human protection against HIV, in which the leading role is played by CCR5 receptor mutations, mutant receptor CCR5-32 in particular, is considered. The extra-African origin of HIV is hypothesized.     

单剂量Nevirapine母婴阻断与HIV

全球艾滋病的流行形势日趋严重,2007年15岁以下儿童感染者为250万,其中大部分是母婴传播,新感染人数为42万,死亡人数为33万,妇女艾滋病感染者为1540万[1].如果不接受抗病毒治疗,HIV感染儿童的预后很不乐观,大约有50%儿童在2周岁之前死亡[2,3].     

The relation between nitrite inhalants, unprotected receptive anal intercourse, and the risk of human immunodeficiency virus infection.

The role of nitrite was evaluated between 1985 and 1988 in a study of sexual transmission of the human immunodeficiency virus (HIV) among homosexual male couples in Boston, Massachusetts. Initial enrollment data suggested that a history of unprotected receptive anal intercourse (odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.4-3.6) and a history of nitrite use (OR = 1.7, 95% CI 1.1-2.5) were independent risk factors for HIV infection. In addition, interaction between nitrite use and unprotected receptive anal intercourse was observed (OR = 5.5, 95% CI 2.8-11.1) after controlling for number of unprotected receptive anal sex partners and history of sexually transmitted diseases. Since it was felt that nitrite use might be a marker for unprotected receptive anal sexual activity, a supplemental questionnaire was administered to obtain information on simultaneous nitrite use and unprotected receptive anal intercourse. The supplemental data suggested a strong interaction between nitrite use and unprotected receptive anal intercourse in increasing the risk of HIV infection. In the adjusted analyses, the odds ratio for HIV infection was considerably greater among men who always used nitrites during unprotected receptive anal intercourse (OR = 31.8, 95% CI 12.9-76.7) compared with men who sometimes (OR = 7.1, 95% CI 2.1-23.6) or never (OR = 9.0, 95% CI 2.5-32.1) used them. These findings have preventive public health implications and may add insight into our understanding of the mechanism by which HIV infection spread rapidly among homosexual men in the early 1980s.     

Collaborative education regarding prevention of human immunodeficiency virus transmission in healthcare settings--Ghana.

OBJECTIVE: To evaluate the effectiveness of a collaborative and participatory approach to professional training to reduce the risk of human immunodeficiency virus (HIV) transmission. SETTING: Healthcare settings in Ghana. METHODS: Two 5-day workshops were conducted for high-level nurse educators and leaders who could contribute to national policy development. A combination of didactics, skill development sessions, field experiences, and development of draft national guidelines and curriculum were used. Outcomes evaluated were pre-to-post training changes in HIV knowledge and attitudes and changes in practice within selected healthcare settings. One-month follow-up visits (times not specified to participants) were used to evaluate outcomes. RESULTS: At post-test, significantly fewer participants thought HIV was transmitted by saliva, sweat, or tears (chi square, p less than .0001), and significantly fewer reported hesitation to care for an HIV-infected patient because of lack of understanding about mode of transmission or because of lack of supplies, such as gloves (chi square, p less than .01). In field observations, there was an overall 42% improvement in specific infection control practices. CONCLUSIONS: A collaborative and participatory approach to training can result in significant changes in infection control practices, even in settings with limited resources.