COVID-19: How close is the world to HIV vaccine?

Researchers have taken remarkable steps towards developing a novel type of vaccine regimen that could protect people against HIV. In this report by SADE OGUNTOLA, experts say that it is important to note that further research and several more clinical trials will be necessary to develop and test later stages in the vaccine regimen before the HIV vaccine is really available for use.

Scientists at the International AIDS Vaccine Initiative (IAVI) and Scripps Research in San Diego are experimenting with the COVID-19 vaccine technology as a way to treat HIV.  They have developed the first mRNA-based vaccine that has shown promise to prevent HIV infection in Phase I trials.

The vaccine, which has an efficacy of 94.1 per cent, successfully stimulated the production of the rare immune cells needed to generate antibodies against HIV. This is being developed to act as an immune primer to elicit the production of different types of broadly neutralising antibodies (bnAbs).

Stimulating the production of bnAbs has been pursued as a holy grail in HIV for decades. But it is hoped that these specialised blood proteins could attach to HIV surface proteins called spikes that will allow the virus to enter human cells, and disable them through a difficult-to-access regions that do not vary much from strain to strain.

This is an approach vaccine researchers have been studying for the past two decades. Following effective clinical trial results and millions of successful vaccinations with mRNA-based COVID-19 vaccines, researchers are looking into how the discovery could make headway in the treatments of other diseases like cancer, HIV and Parkinson’s.

The World Health Organisation (WHO) estimates that there were 1.7 million new infections with HIV in 2019 with 690,000 people dying from HIV-related causes. Preliminary results of the Nigeria HIV/AIDS Indicator and Impact Survey suggest there are 1.9 million people under the age of 64 living with HIV in Nigeria.

Historically, much of the difficulty in creating an HIV vaccine stems from the fact that HIV is a retrovirus — meaning that it readily mutates to avoid being thwarted by antibodies, the proteins created by the immune system to help identify and destroy foreign threats. Because the HIV spike proteins generally remain the same, even among different HIV strains, a vaccine that creates more broadly neutralising antibodies could train them to target those needles — and in the process, inoculate people against HIV.

In a Phase I Clinical trial that began in 2018, the scientists gave 48 participants two doses of the vaccine, spaced two months apart. Results show that in 97 per cent of recipients the vaccine stimulated the immune system to produce immunoglobulin G (IgG) B cells—a first step to making rare but powerful antibodies required to protect against various strains of HIV.

Professor David Olaleye, a virologist at the University of Ibadan, says unlike the COVID-19 vaccine, tackling a more stable virus, a good vaccine for HIV will consider that it readily mutates to avoid been identified and destroyed by the body’s immune system.

Olaleye said the mRNA-based vaccine development is exciting and the mRNA-based HIV vaccine will be released after it had passed all the clinical trial phases, unlike the COVID-19 vaccines that was allowed because there was an emergency.

He, however, added, “we will not know until about a year of the vaccine and its follow up, how long people who are vaccinated are protected, whether they still have the antibody or if the antibody is still protective and so on because of the high mutation of HIV.”

Dr Abdulazeez Anjorin, a medical virologist and senior lecturer in the department of microbiology at the Lagos State University said the fact that mRNA technology is expected to mimic the virus in such a way that it will produce neutralising antibodies to take care of the different strains of the virus makes it totally different from all other failed HIV vaccine trials in the past.

Dr Anjorin said the progress made on the novel vaccine approach for the prevention of HIV is good but hoped that its development will not be hindered by funding and ethical issues, like many other vaccines.

He declared: “Human right ethics is a crucial and germane issue when it comes to vaccination; people must be willing to be used for the clinical trial. So many vaccine candidates would probably have scaled through if the whole world had rallied round as they did for covid-19.”

Professor Morenike Ukpong-Folayan, the coordinator, New HIV Vaccine and Microbicide Advocacy Society (NHVMAS), stated that before now, mRNA technology had been used to develop treatment for diseases, some of which are in the clinical trial phases.

According to her, the first mRNA based vaccine was developed for Ebola disease, but the mRNA HIV-based vaccine is the first-of-its-kind vaccine using mRNA to go into clinical trials.

Nonetheless, she added “while there might be some excitement about it, I am sure that HIV activists would most likely not be jumping up and down over this because it’s all still in the early clinical stages. Hopefully, they might be able to produce considerable results.”

Professor Ukpong-Folayan stated that “an mRNA based HIV vaccine would not work the same way as the COVID-19 vaccine because their causative agents are completely different. The COVID-19 virus, which resembles the flu virus is not like HIV that mutates significantly faster. And therefore there’s a likelihood, not certain, that the jab might need to be taken yearly or repeated doses of the vaccine taken to stay covered.”

Ukpong-Folayan said there is a possibility of requiring multiple doses of the jab even though it is developed based on mRNA, just as from previous experiences on new vaccines, individuals require multiple doses initially to ensure lifelong protection.

“Initially, with yellow fever, you have to take it once every 10 years. But now, it is once in a lifetime. With development, vaccines improve,” she said.

She said it was outstanding that the mRNA based HIV vaccine stimulated the production of the rare immune cells needed to generate antibodies against HIV in 97 per cent of participants unlike the last HIV vaccine candidate with 30.4 per cent efficacy.

Mr. Oba Oladapo, Executive Director, PLAN health Advocacy and Development Foundation said researchers had continually worked on HIV vaccine development but only announce when they achieve some successes.

He stated: “from development in new antiretroviral therapy, it is obvious that we are also getting closer to developing an HIV vaccine. For example, there are ARVs under clinical trials that you only take once in 3 months, meaning that there is a higher possibility of a better and more effective solution to HIV.”

Mr Oladapo, however, said mRNA based HIV vaccine, having the resemblance of definite protection against HIV is a pointer that no matter the disease plaguing man, a solution will finally come but it might just take some time.

“If we eventually get the HIV vaccine, what will be left is to ensure access to everyone, irrespective of their ability to be able to pay,” he added.

Meanwhile, the mRNA-based HIV vaccine study sets the stage for additional clinical trials that will seek to refine and extend the approach—with the long-term goal of creating a safe and effective HIV vaccine. Also, scientists say the same approach can be used to develop vaccines for other challenging pathogens, such as malaria and influenza, dengue, Zika, and hepatitis C viruses, including cancer and Parkinson’s disease.

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