HIVR4P 2024: “HIV is too smart,” toughening vaccine development, says Dr Sandhya Vasan

By Avit Ndayiziga

During the  5th HIV Research for Prevention Conference that kicked off this Sunday morning, 6 October 2024, in Lima, Peru, in Latin America, Dr. Sandhya Vasan cleared all assumptions about the absence of an HIV vaccine for over 40 years. According to this investigator, the complex nature of HIV and its rapid mutation are to blame instead of assuming that HIV is a profitable business.

The 5th HIV Research for Prevention Conference, hosted by the  International AIDS Society, has gathered the global scientific community of doctors, investigators, delegates, and media to discuss the challenging and fast-growing field of HIV prevention research. This conference is taking place from 6-10 October 2024 at the Westin Lima Hotel & Convention Center and Virtual.

However, before landing in Lima, Peru, when flying over the Atlantic Ocean with the Boeing 777-300 at a cruising altitude of 31,000 feet and 885 mph, approximately 769.5 knots, I gazed at the wondrous sky through the aircraft window, and then a thought crossed my mind.

I wondered how engineers have crafted such a beast that flies in the sky for more than 15 hours nonstop without any visible rope to hold it up.

This reflection awakened several assumptions I had heard in the community regarding the absence of an HIV vaccine and a single-shot cure, as it has been over 40 years since the virus first emerged.

The assumptions undoubtedly tackle people involved in the HIV response: “The HIV vaccine or cure will never be available because HIV has become the most profitable industry. Something that confirms it is that people involved in the HIV response are not living with HIV to feel the struggles and pain it brings every day. 

Do you imagine what it feels like to swallow pills every day? They are instead businesspeople who strive to keep their businesses thriving on the blood of others.  If a vaccine or cure were to be discovered, it could put their businesses at risk. Therefore, it will never happen, as they work tirelessly to delay or block it forever. Assumes the community.

After reflecting on these assumptions, I felt a bit convinced that they might hold some truth, as it’s hard to ignore the fact that people have produced nuclear weapons capable of destroying the world in the blink of an eye.

HIV vaccine or cure an uphill struggle

So, why is developing an HIV vaccine or cure an uphill struggle or a tough puzzle? For COVID-19, the vaccine was developed and delivered within a year. Maybe there’s something to these assumptions, after all, I thought to myself.”

When asked, Dr. Sandhya Vasan, who leads global infectious diseases research for HJF and is the principal investigator representing HJF for the Military HIV Research Program (MHRP) and Emerging Infectious Diseases Branch at the Walter Reed Army Institute of Research (WRAIR), in the USA, denied all the assumptions and clearly answered that the lack of understanding the complex nature of HIV leads people to make such statements.

Dr. Sandhya Vasan, principal investigator representing HJF for the Military HIV Research Program (MHRP) and Emerging Infectious Diseases Branch at the Walter Reed Army Institute of Research (WRAIR), USA.

“The notion that the existence of effective HIV vaccines and cures would threaten our business is a misconception. In reality, the field of infectious diseases is vast, and there will always be new challenges to address. Vasan argued.

Sometimes, fear or a lack of understanding leads to such statements. She noted, adding that “there is no fear of going out of business because, let’s say, that day comes when we do make an HIV vaccine that can be effective. There will still be no shortage of work to do. And it will create opportunities for new business.” She noted.

What explains the absence of an HIV vaccine at this time?

To answer the question,  Dr. Sandhya Vasan did not stick around the bush. ”Honestly, the biggest reason that we don’t have an HIV vaccine is because HIV is too smart,” said the doctor.

A vaccine creates antibodies to help the immune system recognize and fight specific pathogens, such as viruses or bacteria.

“HIV is classified as a retrovirus because it integrates its genetic material—either DNA or RNA—into the DNA of host cells. This integration allows the virus to remain dormant for extended periods, sometimes even years.

Therefore, even if a vaccine successfully eliminates all detectable viruses in the bloodstream, HIV can still be lurking within the cells, potentially reactivating later and leading to viral resurgence.”

HIV hides itself in the brain and the gut

The principal investigator continued to explain how “HIV can hide in various locations throughout the body, including the brain and the gut. In particular, the brain presents a significant challenge because there are areas where antibodies do not effectively penetrate. This creates a substantial hurdle that distinguishes HIV from other viral infections and their vaccines. 

HIV mutates rapidly

Additionally, HIV mutates at an extraordinarily rapid rate. This is why you often hear about different subtypes or clades of the virus, as various regions of the world harbour distinct variants.

These subtypes can intermingle, resulting in a complex landscape that doesn’t conform to simple classifications. To draw a comparison, consider influenza: it varies enough each year that we need to develop a new flu vaccine annually. 

The same principle applies to HIV, making vaccine development particularly challenging.”

“We currently have distinct flu vaccines for the northern and southern hemispheres, but the situation with HIV is considerably more complex. The diversity of HIV and its rapid mutation rate far exceed that of the influenza virus.

Early vaccine development efforts focused on specific regions, such as creating subtype B vaccines for the United States and subtype C vaccines for South Africa. 

However, in our interconnected world, where people travel extensively, this regional approach has proven challenging. 

Even matching vaccines to specific subtypes has been difficult. What we truly need is a global solution that transcends regional distinctions, rather than asking individuals whether they will receive a West African, South African, or Asian vaccine. 

As you can see, these practical challenges complicate our efforts to develop an effective and universally applicable HIV vaccine.” Sandhya Vasan concluded, mentioning that the smartness and complexity of the virus will not stop them from trying or changing their determination.

 No single-shot cure for the virus.

Aside from the lack of effective HIV vaccines, there is also no single-shot cure for the virus.

Professor Sharon Lewin, an internationally recognized infectious diseases physician and researcher specializing in all aspects of HIV, particularly in strategies aimed at achieving a cure, explains that HIV’s replication mechanism complicates treatment efforts.

The virus targets activated CD4 T cells, integrating its genetic material into the DNA of these cells. As a result, it produces billions of copies of itself before ultimately causing the host cell to die.

The professor kept on explaining how treatment changes the course and the complexity of HIV. “When treatment is initiated, it halts this replication process, leading to the death of most infected cells, leaving very few, if any, productively infected cells. 

However, the challenge lies in HIV’s ability to establish what is known as latent infection, a characteristic not shared by many other viruses. For instance, viruses like COVID-19 and measles do not exhibit this behaviour.

 The latent form means that while the virus integrates its DNA into the host cell, it remains inactive—essentially ‘silent.’ As a result, although the cell is DNA positive for HIV, it does not produce viral RNA or proteins. This lack of expression prevents the immune system from recognizing these infected cells, allowing them to persist undetected.” She concluded.

The HIV prevention pipeline

While there is currently no vaccine or single-shot cure for HIV, the global scientific community has made significant strides in developing a range of tools for HIV prevention and treatment. These include methods that are currently in use, newly approved interventions, and promising strategies still in development. We will explore these advancements in detail in our upcoming articles.

The International AIDS Society funded this story through the HIVR4P Journalist Fellowship programme

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