MONICA KAYOMBO, Lusaka
THE development of COVID-19 vaccines over the last two years has renewed hopes that a vaccine for the prevention of HIV (human immunodeficiency virus), a virus that attacks the body’s immune system, will soon be developed. After more than 30 years of research around the HIV vaccine, challenges remain in the process of developing an HIV vaccine. This is due to the genetic diversity of HIV and the need for substantial financial resources and increased capacity. While treatment (ART) for HIV has helped many people, there is still no vaccine to prevent HIV infection. Gavi, the vaccine alliance, says vaccines are among the most cost-effective investments in health and development. Zambian HIV specialists and activists are urgently calling for an increase in funding and resources to find a vaccine for HIV, a virus which was discovered in the 1980s. The HIV prevalence in Zambia stands at 11.1 percent, according to the United Nations Programme on HIV/AIDS (UNAIDS) 2020 report. HIV prevalence among females aged 15-49 years is 14.2 percent, compared to 7.5 percent for males of the same age, this is according to the Zambia Demographic and Health Survey of 2018. The Copperbelt and Lusaka provinces have the greatest HIV burden with a prevalence of 15.4 percent and 15.1 percent respectively. Prevalence rates for other provinces are: Western Province 10 percent, North-Western Province 9.5 percent, Southern Province 8.2 percent; and Muchinga Province being the least burdened at 5.4 percent. Some sections of society believe that the COVID-19 pandemic outbreak, to some extent, contributed to the delay in having an HIV vaccine. Centre for Family Health Research in Zambia (CFHRZ, formerly ZEHRP) director William Kilembe said SARS-Cov-2 is self-limiting since many people are likely to survive even after getting infected with it. “HIV is different because the disease is not self-limiting, and once someone gets it, if there is no intervention, 100 percent of those affected will get the virus that would lead to AIDS. HIV is the most diverse virus,” Dr Kilembe said. He explained that the appearance and function of HIV is diverse, meaning that it has many variants which make developing an effective vaccine more complicated. “HIV works by depleting the main core of your immune system. COVID-19 usually infects other cells and the receptors are different from those of HIV,” he explained. HIV mutates rapidly and makes copies of itself once every 24 hours, and this means that variants can emerge at a very high rate compared to other viruses. As a result, there are 60+ dominant strains of HIV and a multitude more variants. An effective vaccine would have to be able to work against multiple “versions” of the virus.
He said developing an HIV vaccine has taken time because there is no guaranteed protection, and that scientists want to discover an HIV vaccine that prevents transmission totally.
HIV vaccine trials
Dr Kilembe says globally, there are many trials that are taking place though they are at different stages. “The only phase three clinical trial that I know is one that was a follow-up on the HB10706 or Mosaic Trial that is being conducted in the United States,” he said. Dr Kilembe also referred to the novel African HIV vaccine trial, also known as HIV CORE-006, which started in 2020 and seeks to evaluate safety, tolerability, and immunogenicity of the vaccine candidate. It is a phase1 trial with 88 participants. Dr Kilembe said the HVTN 706 also known as Mosaico. Imbokodo HIV vaccine trial in Zambia, South Africa, Zimbabwe and Malawi which began in 2017 was stopped early in 2020 because the researchers needed to inform people that the vaccine did not provide adequate protection against HIV. “The vaccine in itself was very safe but we found that it did not provide adequate protection,” Dr Kilembe said.
Dr Kilembe said mRNA is a new technology platform for developing vaccines. It has been used very effectively for the first time to develop COVID-19 vaccines manufactured by Moderna and Pfizer BioNtech. It is now hoped that mRNA technology can be successfully used to develop HIV vaccines. The International Aids Vaccine Initiative (IAVI) and Moderna launched in January this year a phase one trial of HIV vaccine antigens using mRNA technology. Dr Kilembe said the COVID-19 pandemic has affected the fight against HIV because most resources are being diverted to the fight against COVID-19. Scientists in Zambia have advised Government against defunding HIV programmes to avoid spikes in HIV cases and increased mortality.
Director in charge of infectious diseases at the Ministry of Health, Professor Lloyd Mulenga, said, “No one in the world is able to predict when we will have the HIV vaccine because of the many complications surrounding the virus.” Asked if Zambia has started using injectable cabotegravir for treating HIV, Prof Mulenga said it is not yet available in Zambia as it has not yet been approved by the World Health Organisation. The United States regulatory authority, FDA, has approved the treatment for use in that country. According to UNAIDS, this is the first time an injectable antiretroviral drug has become available as a pre-exposure prophylaxis (PrEP) for prevention of HIV. “The long-acting formula is a step forward and a valuable addition to the HIV prevention toolbox and will make acceptance and adherence easy,” UNAIDS said on its website. Prof Mulenga said Zambia has 1.2 million people on antiretroviral treatment (ART), and having cabotegravir would mean having those on ART lining up to get the injection. The HIV vaccine is taken initially as two injections one month apart, and then after every two months afterward, it could offer a better choice for adults and adolescents at substantial HIV risk who either do not want to take or struggle with taking a daily tablet. He said the Zambian government does not have a budget for HIV vaccine trials and the country relies on sponsors for such undertakings. He said coronavirus has accelerated the research for an HIV vaccine due to the technology platforms that have been used for COVID-19 vaccines, particularly mRNA technology. Prof Mulenga said on the negative side, some funds that were meant for the fight against HIV have been diverted towards the fight against COVID-19, and that some of the HIV drugs are not available due to lack of some components from China, which was on lockdown for some time. The equipment that is used for testing HIV viral load is the same one being used for testing for coronavirus, and that has had an effect on the HIV programme. He said the indication is that the HIV prevalence in Zambia remains at 11.1 percent, and that the Zambia Population-Based HIV Impact Assessment (ZAMPHIA) report to be released in June this year is likely to give more statistics on the HIV prevalence rate in all parts of the country. He said the HIV fight requires concerted efforts from all stakeholders globally and at national level. National Aids Council (NAC) in Zambia director of policy and planning John Mwale says there is need for a vaccine to protect people against contracting HIV in addition to the existing HIV prevention interventions such as pre-exposure prophylaxis (PrEP) and others. “We hope positive results of these trials can be seen and made available soon. We are remaining with eight years before the year 2030, hence the need for researchers and donors to expedite these trial processes and support,” Dr Mwale said. He agrees that COVID-19 has had a negative impact on the people living with HIV, especially those that stopped treatment. He noted that Zambia has seen a reduction in community and facility HIV testing services, resulting in low new positive cases and new patients starting ART. There has also been a reduction in viral-load suppression and retention of patients in care. “In some cases [there is] substantial disruption in the supply chain of ARV drugs,” he said. Treatment, Advocacy and Treatment Campaign (TALC) treatment and literacy officer Owen Mulenga said there are five countries in Africa conducting HIV vaccine trials phase one and phase two: Uganda, Kenya, Rwanda, South Africa and Zambia. He said according to TALC, the HIV infection rate in Zambia in the recent past has increased from 46,000 cases per year in 2016 to 52,000 in 2021. Mr Mulenga said COVID-19 has affected the HIV response by affecting the HIV testing and treatment commodities supply chain. In addition, most people living with HIV stopped going to health facilities for fear of getting infected with COVID-19.
HIV activist John Nkhata said despite being aware of many challenges encountered in the journey for an HIV vaccine development, he feels the exercise could be speeded up if certain measures were put in place. He said poor funding and lack of technology have immensely contributed to the delay in having an HIV vaccine. “We need to rise up and find the solution. We always want to depend on the West for solutions. “Scientists have to find solutions to two problems: how does HIV respond to the human body and how does the human body respond to the mechanism that defeats the virus?” Mr Nkhata said. He said in order to quickly find an HIV vaccine, there’s need for many stakeholders to come on board and sponsor research programmes.
The story was supported by: International Women’s Media Foundation (IWMF).