Virological evaluation of the 'Ottawa case' indicates no evidence for HIV-1 superinfection

Reducing Risk: Counseling Men Infected with HIV Who Have Sex with Men on Safer Sex Practices with Seroconcordant Partners

The incidence of new HIV infections in the United States continues to be greatest among men who have sex with men (MSM). MSM infected with HIV often seek seroconcordant sexual partners based on intent to limit psychosocial, legal, and health risks they perceive as higher with serodiscordant sexual partners. However, the rationales for limiting sexual relationships exclusively with other MSM infected with HIV may be rooted in misinformation or misperception. Thus, these clients may have a unique sexual health knowledge deficit that nurses, social workers, and other clinicians need to address to help them reduce risk. This article focuses on sexually related health risks that are distinct to MSM infected with HIV seroconcordant partners. Data on the most recent HIV-infection incidence rates in MSM in the United States is provided. Discussion concentrates on the risk these individuals may have in communicating and acquiring sexually transmitted diseases other than HIV, the risk of HIV superinfection, and how sexually transmitted diseases affect persons who are immunocompromised differently than those who are immunocompetent. Finally, recommendations for healthcare professionals who counsel MSM infected with HIV in sexual decision making is provided.

Repressive effect of primary virus replication on superinfection correlated with gut-derived central memory CD4(+) T cells in SHIV-infected Chinese rhesus macaques

A possible mechanism of susceptibility to superinfection with simian-human immunodeficiency virus (SHIV)-1157ipd3N4 was explored in twelve SHIV_SF162P3-infected Chinese rhesus macaques. Based on the kinetics of viral replication for the second infecting virus following SHIV-1157ipd3N4 inoculation, the monkeys were divided into two groups: those relatively resistant to superinfection (SIR) and those relatively sensitive to superinfection (SIS). We found that superinfection-resistant macaques had high primary viremia, whereas superinfection-sensitive macaques had low primary viremia, suggesting that primary SHIV_SF162P3 infection with a high viral-replication level would repress superinfection with a heterologous SHIV-1157ipd3N4. Although no correlation of protection against superinfection with virus-specific CD4⁺ T cell or CD8⁺ T cell immune responses from gut was observed prior to superinfection, superinfection susceptibility was strongly correlated with CD4⁺ Tcm cells from gut both prior to the second infecting virus inoculation and on day 7 after superinfection, but not with CD4⁺ Tem cells from gut or with CD4⁺ Tcm cells from peripheral blood and lymph node. These results point to the important roles of gut-derived CD4⁺ Tcm cells for the study of the mechanisms of protection against superinfection and the evaluation of the safety and efficacy of vaccines and therapies against acquired immune deficiency syndrome (AIDS).

Frequency and implications of HIV superinfection

HIV superinfection occurs when an individual with HIV is infected with a new distinct HIV viral strain. Superinfection has been reported throughout the world, and studies have recorded incidence rates of 0-7·7% per year. Use of next-generation sequencing has improved detection of superinfection, which can be transmitted by injecting drug use and sexual intercourse. Superinfection might have incidence rates comparable to those of initial HIV infection. Clinicians should encourage safe sexual and injecting drug use practices for HIV-infected patients because superinfection has detrimental effects on clinical outcomes and could pose a concern for large-scale antiretroviral treatment plans. The occurrence of superinfection has implications for vaccine research, since it seems initial HIV infection is not fully protective against a subsequent infection. Additional collaborative research could benefit care of patients and inform future vaccine design.

HIV-1 superinfection

PURPOSE OF REVIEW

This review describes the nature and frequency of HIV-1 superinfection and provides advice regarding counselling of patients in accordance with national guidelines.

RECENT FINDINGS

Recent studies have demonstrated conflicting results, from no superinfection to an incidence of over 18%. We discuss the difficulties comparing studies due to population and methodological differences.

SUMMARY

HIV-infected individuals should be counselled that there is risk of superinfection at all stages of HIV, but this is unlikely to be clinically significant unless transmission of resistance occurs. The risk may be as high as the risk of new incident infection in the presence of on-going exposure.

Messages HIV clinicians use in prevention with positives interventions

Prevention with Positives (PwP) is a component of the US HIV prevention strategy that targets HIV-infected persons who are aware of their seropositive status. This paper examines the use of prevention messages by clinical providers during the PwP intervention period of the US Health Resources and Services Administration's Special Projects of National Significance program. Quantitative approaches were used to learn which prevention topics were most discussed and qualitative interviews were also utilized to better understand the clinician perspective in providing prevention counseling. At 12-month follow-up, there was a significant increase in the percent of patients receiving all PwP counseling messages (p<0.01). Providers reported discussing safer sex with 91% of patients when sexually transmitted infection (STI) screening was conducted during a visit, an increase from baseline (83.5%). The percent of providers reporting they regularly explained the risk of superinfection to their clients also increased from 75% at baseline to 90% at 12-month follow up (p<0.001). Qualitative data suggest that providers prioritize individual care over public health approaches to PwP in counseling. Discussing superinfection offered providers a way to discuss HIV prevention from a non-judgmental clinical perspective while focusing on a patient-centered philosophy of care. However, the threat of superinfection may not be the best counseling option. Examples such as STI screening, giving messages to reduce the number of sexual partners and adherence to medication, are more evidence-based approaches to changing HIV transmission risk behavior and may be more important in PwP. Findings suggest that in order for HIV care providers to incorporate HIV prevention discussions into their practice, acceptable approaches to speaking about risk behavior and prevention of HIV transmission must be developed.

HIV Type 1 Superinfection with a Dual-Tropic Virus and Rapid Progression to AIDS: A Case Report

BACKGROUND

The occurrence of human immunodeficiency virus type 1 (HIV-1) superinfection has implications for vaccine development and our understanding of HIV pathogenesis and transmission.

METHODS AND RESULTS

We describe a subject from the Multicenter AIDS Cohort Study who was superinfected with a dual-tropic (CXCR4/CCR5-utilizing) HIV-1 subtype B strain between 0.8 and 1.3 years after seroconversion who had rapid progression to AIDS; the subject developed Pneumocystis pneumonia 3.4 years after seroconversion, as well as multiple other opportunistic infections. The superinfecting strain rapidly became the predominant population virus, suggesting that the initial and superinfecting viruses in this individual differed in virulence. However, we found no molecular epidemiological evidence in the HIV database to suggest that this strain had been found in other individuals. In addition, this subject's HIV-1 viral load and pattern of human leukocyte antigen and coreceptor polymorphisms only partially explained his rapid disease progression.

CONCLUSIONS

Additional studies are needed to determine whether superinfection itself and/or infection with a dual-tropic virus causes rapid disease progression, or whether certain individuals who are innately more susceptible to rapid disease progression also lack the ability to resist the challenge of a second infection. This case appears to support the latter hypothesis.

HIV-1 superinfection and viral diversity

OBJECTIVE

Sequential acquisition of viral variants, or HIV-1 superinfection, has been proposed to explain the high fractions of recombinant viruses observed in some geographical regions, but only a few cases of superinfection in humans have been reported. Animal models suggest that susceptibility to superinfection may be restricted to a short period of time after initial infection, possibly due to maturation of broad antiviral immune responses.

METHODS

A mathematical model involving a system of differential equations was developed to identify transmission and superinfection patterns that would lead to the observed global patterns of viral diversity.

RESULTS

Requirements for a high prevalence of infections involving recombinant viruses include high viral infectivity, the presence of highly sexually active core groups, and introduction of divergent viruses early in the epidemic spread of HIV-1. Restricted superinfection could explain the persistent predominance of single virus subtypes in regions with well-established HIV-1 epidemics. The rate of recombination within individuals was not strongly related to recombinant fractions in populations.

CONCLUSIONS

HIV-1 superinfection restricted to early HIV-1 infection could account for the high fraction of recombinant virus infections observed in populations. The relationship between recombination in cellular infections and recombinant fractions in populations is complex and depends on epidemiological factors and biological factors that can be modeled.