By Kuda Pembere
A clinical research study to assess the safety and efficacy of a new HIV vaccine is set to begin in Zimbabwe in May this year. The study will be coordinated across three sites: Mutala in Zimbabwe, the Desmond Tutu Health Foundation in Cape Town, and the Africa Health Research Institute in Durban.
The research follows findings that countries in sub-Saharan Africa, including Zimbabwe and South Africa, face a high risk of new HIV infections and continue to experience unacceptably high rates of mother-to-child transmission.
Speaking to nurses and doctors at Parirenyatwa Group of Hospitals on Thursday, Dr. Yeukai Musodza, the lead researcher for Zimbabwe, explained that the vaccine was developed with support from the Gates Foundation and other partners. The vaccine, named GRAD HIV-NE1, utilizes a gorilla-derived adenovirus vector.
This vaccine contains components derived from the HIV virus, presented in vaccine form and delivered using an adenovirus vector,” said Dr. Musodza.
“The immunogen—essentially the antigen part of the vaccine—stimulates the immune system. We have learned from patients known as ‘elite controllers,’ who live with HIV for decades without antiretroviral therapy (ART) and remain physically healthy. Many of them are even virally suppressed without medication.”
“These individuals mount a very strong CD8 immune response, particularly against parts of the HIV virus that do not mutate. That’s crucial because the biggest challenge with HIV is its ability to change rapidly,” she added.
Dr. Musodza stated that the study aims to enroll 120 participants across the three sites. The initial phase will evaluate the vaccine’s safety in HIV-negative individuals aged 15 to 50. Later phases will include participants who are HIV-positive.
“This is a phase one, first-in-human study, and it’s structured in two parts: one for HIV-negative individuals (Part A), and the other for people living with HIV (Part B),” she explained. “We begin with HIV-negative participants to assess safety before proceeding to those who are HIV-positive. Enhanced safety measures are essential for this group.”
A total of 120 participants will be recruited—some will receive the vaccine, while others will be given a placebo. The study spans 18 months. Participants will receive their assigned product (vaccine or placebo) at the start of the study and again after six months. They will then be followed for an additional year.
“The primary goal is to assess the vaccine’s safety and tolerability in both HIV-negative and HIV-positive individuals,” said Dr. Musodza. “Secondary objectives include evaluating whether the vaccine triggers an immune response, how strong it is, and how broad the response might be.”
Participants will be adults aged 18 to 50, of both sexes. Sexually active women of childbearing potential must use effective contraception—such as an IUD, hormonal methods, or verified partner vasectomy—for at least 21 days before vaccination. They must also refrain from donating blood or other tissues during the study.
“For HIV-positive participants, we are only including individuals who are in good health,” said Dr. Musodza. “This means no significant comorbid conditions. For example, if someone develops severe hypertension shortly after vaccination, we must consider a possible link.”
Participants must have a CD4 count greater than 500 at screening. While CD4 counts are no longer routinely performed in many HIV clinics, they will be used here for screening purposes. HIV-positive participants must also have been on ART for at least 12 months and have a viral load under 50 copies/ml, maintaining their regimen throughout the study.
“This is a safety trial—we are not yet testing the vaccine’s ability to prevent HIV. That will be addressed in future phases (Phase 2 and 3),” she emphasized.
During the session, Dr. Mhlanga, Clinical Director at Parirenyatwa Group of Hospitals, raised concerns about how the difference between preventive and therapeutic vaccines is communicated. He stressed the importance of ensuring that participants understand that, like all vaccines, this one is not guaranteed to be 100 percent effective.
The study will be blinded, meaning participants will not know whether they are receiving the vaccine or a placebo.
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