World AIDS Day: 41 Years On, Why Don’t We Have HIV Vaccines Yet?

Preventive treatment for HIV has been around for a while now. Why isn't it part of public health strategies?

World AIDS Day 2022: All about PrEP Preventive treatment, HIV vaccines.

(Photo: FIT)

It took over twenty years to develop the polio vaccine. Fast-forward to 2022, and the COVID vaccine was developed in a record time of just months since the virus was identified.

So, in a world where we are making such strides in vaccine technology, one question that pops up is, where is the HIV vaccine?

HIV is one of the most pressing health crises that still plagues the world today. There were approximately 38.4 million people with HIV - the virus that causes AIDS - in the world in 2021.

Over 50 percent of them were women.

It's proven to be a particularly challenging virus to tackle.

This World AIDS Day, let's take a closer look at what's keeping the HIV vaccine, and more importantly, do we have any plan-Bs?

Why Is the HIV Vaccine So Challenging?

Scientists have been working hard to develop an HIV vaccine. In fact, some experimental vaccines have even shown promise.

In 2021, one such vaccine sponsored by pharmaceutical company Johnson & Johnson made it to a population of young women at high risk of getting HIV in Africa.

But it ended up failing to protect them from getting HIV, just like all the other experimental vaccines.

Why has it been so challenging to make an HIV vaccine? There are a few reasons.

• Genetic complexity of the virus

"HIV mutates rapidly and imperfectly within a population, as well as within an individual. As a result, it can become resistant to the immune defenses created by vaccines very quickly, just like it can develop drug resistance," explains Dr Jayanta Bhattacharya, Director at International AIDS Vaccine Initiative (IAVI) & Head, Antibody Translational Research.

This makes it challenging to create one airtight vaccine that could protect against all strains. Some are bound to 'seep through'.

For instance, even with newer technology, the efficacy of the Jansen vaccine in this trial (at its best) was estimated at just 25 percent.

• Basic principles of vaccines fail

Traditionally, vaccines work by 'training' killer white cells to attack and neutralise specific pathogens upon infection. But these are the very cells the virus attacks and destroys.

The virus also has the ability to hide parts of it from the immune system, to distract, and overwork the immune system into what's called 'immune exhaustion' as a diversion.

• Clinical trials are challenging

"As the virus only affects human beings, there is no fully adequate model for early testing of candidates in animals," says Dr Jayanta Bhattacharya.

The quest for an HIV vaccine has seen many setbacks. But, experts believe that the success of mRNA vaccine that are able to adapt to the fast mutating COVID virus may offer some hope in the future of HIV vaccine research.

In the Meantime, We Have Preventive Treatments

Pre-exposure prophylaxis (or PrEP) is a medicine taken to prevent getting HIV. As far as preventive treatments go, PrEP is sort of a trailblazing star.

• It lowers the risk of getting HIV from sex by about 99 percent.

• Reduces the risk of getting HIV from injection drug use by at least 74 percent.

It was first approved by the US against HIV-1 back in 2012. However, 10 years on, why haven't we seen any public health gains from it? Why are so few people even aware of it?

More About PrEP

There are currently two medications for PrEP approved by the US FDA - Truvada and Descovy.

Truvada, the first PrEP medication to be approved in the world, can be taken by adult and adolescent, cisgender and transgender people.

Descovy, on the other hand, is only available for cis-gender males and transgender females currently.

PrEP is not a vaccine. "Because vaccines cause our bodies to make ‘antibodies’ and other components of immunity that fight against infections long after you take the dose," explains Dr Bhattacharya.

"PrEP, on the other hand, only works as long as you keep taking it... while vaccines have a longer shelf life in our bodies."

Dr Jayanta Bhattacharya, Director, IAVI & Head, Antibody Translational Research

Why is PrEP Not More Widely Used?

"The people most in need of PrEP have the most difficulty getting access to it," says Dr Bhattacharya.

This include transgender communities, gay men and other men who have sex with men, people who use injectible drugs, women etc.

"Uptake is also impacted by houselessness (or shifting populations in the case of migrant workers, for instance), financial instability and lack of access to healthcare facilities."

Dr Jayanta Bhattacharya, Director, IAVI & Head, Antibody Translational Research

"PrEP is effective only if taken at the same time every day. This could be mentioned as one of its shortcomings," adds Dr Bhattacharya.

Having to take it consistantly also makes it unafordable for many. In India a month's supply of the treatment can cost around Rs 1,500 to 2,000.

PrEP also has its fair share of naysayers. Many have argued that preventive treatment like this would promote unsafe sex and sexually transmitted infections (STI).

No option is perfect, says Bobby Ramakant, who writes for Citizen News Service, a citizen journalism initiative focused on health communication, policy and advocacy.

This is why it's futile to look for the one, holy grail HIV solution.

PrEP isn't the only preventive tool for HIV. We also have male and female condoms, antiretroviral therapy ((ART) to prevent transmission).

Prioritising Public Health to Fight AIDS

"We have NOT prioritised HIV prevention the way it should be if we are to reduce the rate of new HIV infections more steeply," says Ramakant.

A closer look at the UNAIDS report for 2022 shows that while HIV is not declining, it's not dipping as fast as they should to meet the goal of ending AIDS by 2030.

To truly counter the HIV crisis, Ramakant says, "we need to ensure that a full spectrum of combination preventive options is available, accessible and affordable to all - especially those more at risk of HIV. This includes PrEP. "

"We need to engage regulators manufacturers supply chain experts – everyone who has a role to play – so that we have the ability to ensure the new scientific tools, new diagnostics, new treatments, new vaccines, new prevention options, reach the people in need without any further delay."

Bobby Ramakant, Public Health and Policy Expert, CNS

Dr Bhattacharya adds that adressing the accessibilty and availability of existing treatments like PrEP is also vital.

"Addressing these issues include ensuring the availability of a long acting PrEP option, whether in pill or injectable form, would alleviate many of the barriers people who inject drugs (PWID)."

Dr Jayanta Bhattacharya, Director, IAVI & Head, Antibody Translational Research

"Providing longer-lasting quantities of PrEP is another way of bridging the gap," he adds.

And this is not just a stop-gap measure till vaccines are created. Even when we do make a breakthrough with the vaccine, there are other major wrinkles that would need to be ironed out, like how easily it can be administered, and how affordable and accessible it will be.

Which is why experts reiterate that if we hope to see an 'AIDS-free world' in the near future, we will have to think of public policy measures that are rooted in the combination approach.