On the road to an HIV Vaccine…are we there yet?
Vaccination is the single most effective strategy in controlling infectious diseases throughout history. Vaccines can be produced in large quantities and can be mass disseminated through public health programs in most countries to most people. The side effects are generally minimal and a completed course often provides years or life long protection. Even without access to other public health measures or standard of care treatment, infectious diseases can be well controlled through vaccination.
Early on in the HIV epidemic researchers expected they would have effective treatment and vaccination within a short period of time. This wasn’t the case and even as we speak treatments continue to evolve and develop, often superseding past and current treatments for efficacy, safety, tolerability and ease of use.
There has always been a strong drive towards preventing transmission of HIV in the hope of controlling the spread of the epidemic. Safe sex campaigns, monogamy, early diagnosis, treatment, control of other STIs and now pre exposure prophylaxis (PrEP) have all been significant strategies.
Recently PrEP has attracted much attention as an efficacious prevention method. There is a way to go before this strategy is implemented at a large scale public health level and even then what is seen in studies to date may not reflect what would happen over a number of years in the real world. PrEP also addresses prevention in only a portion of those at risk and on reflection if the current barriers to simple measures such as condoms, diagnosis, treatment and access to standard care exist in most countries, how could an advanced strategy such a PrEP be rolled out in mass numbers having a significant long term effect on the epidemic.
Whilst I am optimistic that a cure (or close to a cure) will be discovered with time, so many people with HIV are not diagnosed and presuming the treatment required for cure is not straight forward, advanced levels of care and intervention will be required to implement this strategy.
Historically, and currently, vaccination programs have reached into most populations of the world and had a high impact on the incidence and ultimate control of infection. Smallpox was even eradicated.
Whilst an effective vaccine for HIV has not been discovered, despite some serious effort and clinical trials, it will be.
Though I am not a scientist in this field, I do reflect that there is an aspect to the immune system, such as it’s use of microRNA, that has not been fully appreciated. Maybe the answer lies there. The other avenue being explored with effort and focus is a broadly neutralising antibody, but this is not eventuating with speed, despite science’s greater understanding of antibody.
On reflection I have often thought that there exists right now in many people’s immune systems, that which is exactly required to prevent infection with HIV, separate from the CCR5 deletion. This must be the case for the sex workers who are repeatedly exposed to HIV but do not develop infection.
So maybe the answer lies in the immune system of these individuals but in a palace where we have yet to look or understand.