Little Promise of Anal Protection From Adult HPV Vaccination

View as:|
1 of 5
Next
jarun011 for iStock via Thinkstock

This week, as we mined recently published journals for HIV-related research, we discovered these four items glittering in the loam:

  • Sobering findings regarding HPV vaccination and anal HPV infection in HIV-positive adults.
  • Encouraging findings regarding single-tablet E/C/F/TDF in the setting of little-studied HIV-2 infection.
  • Informative findings regarding the relationship between an HIV-positive infant's virus and its mother's.
  • Intriguing findings regarding the relative effect on HIV risk from male circumcision compared to an initial scale-up of antiretroviral access in Kenya.

Read on to drill down a little more deeply into each of these studies. To beat HIV, you have to follow the science!

Barbara Jungwirth is a freelance writer and translator based in New York. Follow Barbara on Twitter: @reliabletran.

Myles Helfand is the executive editor and general manager of TheBody.com and TheBodyPRO.com. Follow Myles on Twitter: @MylesatTheBody.


jarun011 for iStock via Thinkstock

Quadrivalent Vaccine in Adults Ineffective Against Anal HPV

A clinical trial of a quadrivalent human papillomavirus (HPV) vaccine in adults living with HIV, many of whom had previously been infected or were currently infected with HPV, was stopped early because the vaccine proved futile in preventing further anal infection in this population. However, it appeared to be more effective against oral HPV infection. The results were published in Clinical Infectious Diseases.

Among people who previously experienced documented persistent anal HPV infection, vaccine efficacy was 21% against a new occurrence. Among people who had no anal high-grade squamous intraepithelial lesions on biopsy (bHSIL) at study baseline, vaccine efficacy was 0% at preventing incident bHSIL. Among people with prior persistent oral HPV infection, which can lead to oropharyngeal cancer, vaccine efficacy was 88% against a new occurrence.

Study authors called for more research into using the vaccine against oral infection but concluded for anal HPV: "This underscores the need to vaccinate boys and girls prior to exposure to HPV infection."


Sylverarts for iStock via Thinkstock

E/C/F/TDF Effective Against HIV-2 in Small Trial

The single-tablet regimen of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (a.k.a. E/C/F/TDF, known by the brand name Stribild) was found effective against HIV-2 in a small trial published in Clinical Infectious Diseases. HIV-2 is a globally less-common (and less-studied) genetic variant of HIV found mostly in West Africa.

The open-label trial was conducted in Senegal. Thirty participants living with HIV-2 -- 80% of whom were women -- with median CD4 cell counts of 408 cells/mm3 and no prior antiretroviral treatment started the study drug, and 29 completed all 48 weeks. At that endpoint, CD4 cell counts increased by a median of 161 cells/mm3 and the virus was suppressed in 28 (93.3%) of participants. However, 25 people had started out with viral loads of < 50 copies/mL; HIV-2 infection is differentiated from HIV-1 infection in that it generally follows a much slower rate of disease progression and features much lower viral load levels.

In addition to showing the safety and efficacy of integrase-based HIV-2 treatment, the study results suggest that a test-and-treat approach for people diagnosed with HIV-2 "would not be unreasonable," even if the person's viral load is low or undetectable, or if their CD4 cell count is greater than 500 cells/mm3, study authors said. Study sponsors included Gilead Sciences, the manufacturer of Stribild, although sponsors had no influence on study design or the manuscript, according to the study's disclosure section.


Dorling Kindersley via Thinkstock

Infants' "Founder" HIV May Be Sensitive to Broadly Neutralizing Antibodies

Even in the absence of treatment, only some of a pregnant woman's HIV virus variants are passed on to her baby. These transmitter/founder viruses then duplicate in the infant. New research published in PLOS Pathogens showed that most of the variants transmitted around the time of delivery were resistant to neutralization by the mother's plasma -- but not resistant to most broadly-neutralizing monoclonal antibodies (bNAbs), a finding with potential implications for improved mother-to-child HIV prevention interventions in resource-poor areas.

Researchers matched stored blood samples from 16 mothers and their HIV-infected infants before the era of effective antiretroviral treatment, collected from the Women and Infants Transmission Study (WITS). Eighty-five percent of the 21 pseudoviruses generated from these samples were resistant to plasma from the infant's mother. However, the viruses were sensitive to most bNAbs, which are being explored as experimental HIV vaccine components.

While antiretroviral therapy for pregnant women has substantially reduced seroconversions among infants, mother-to-child transmissions have not been eliminated. The results of this study may help to develop a vaccine that would boost a pregnant woman's own neutralization of HIV variants in her blood and thereby further reduce the chance of passing the virus on to her baby, an associated press release explained.


thumb via iStock

Male Circumcision Reduced HIV Risk More Than Antiretrovirals in Small Kenya Study

Voluntary medical male circumcision (VMMC) may have contributed to a decline in HIV incidence in one Kenya location -- an impact that cannot be said for the scale-up of antiretroviral therapy in the same location, according to an analysis of population-based surveys conducted in 2011, 2012 and 2016. These results were published in The Lancet.

Overall HIV incidence dropped from 11.1 to 5.7 per 1000 person-years during the period, still well above the target of 1 per 1000 person-years needed to end the epidemic. The odds ratio (OR) of seroconverting was 0.6 for women and girls whose male partner was circumcised, compared to those with a partner who was not circumcised. For people of any gender, this OR was 5.1 if the partner was taking antiretrovirals and 4.7 if the partner was living with HIV but not on treatment, both compared to a partner who did not live with HIV.

Researchers speculated that the lower HIV rates among circumcised men explained the lower seroconversion risk for their partners. By contrast, they theorized that the lack of an apparent protective effect for antiretrovirals may be due to the fact that people on HIV treatment tended to already have advanced HIV disease at the time they started antiretroviral therapy, increasing the likelihood that they had already transmitted HIV to their partners prior to treatment initiation.