A new vaccine provides hope in the fight against the spread of HIV according to new research published in the Lancet. The vaccine produced anti-HIV immune responses in all 393 recipients and proved effective in protecting rhesus monkeys from Human-Simian immunodeficiency virus, which is similar to HIV. This chronic, life-long infection is notoriously difficult to vaccinate against, with factors such as genetic mutation and the sheer number of different strains meaning an effective vaccine has eluded scientists for decades. Could this new vaccine be the much-needed breakthrough in the global fight against HIV?
According to the World Health Organisation, an estimated 36.7 million people are living with HIV worldwide, with around 1.8 million new cases being reported annually. Of those living with the condition, only 20.9 million have access to antiretroviral drugs which prevent the progression of the infection.
This chronic, life-long infection is notoriously difficult to vaccinate against, with factors such as genetic mutation and the sheer number of different strains meaning an effective vaccine has eluded scientists for decades
Currently, the only effective way to medically prevent the spread of the infection is the prophylactic drug PrEP, which needs to be taken for weeks before exposure, as well as daily to maintain its protective effects. This is often costly and only works when the patient is aware of the potential for infection. Previous vaccine trials have found all attempts fail to achieve an efficacy level which would justify mass use.
This new research was pioneered by scientists at Harvard University. In a double-blind, randomised, placebo-controlled trial, vaccines were tested on 393 healthy volunteers between the ages of 18 and 50 across 12 clinics in the US, Rwanda, Uganda, South Africa and Thailand. Scientists used “mosaic” vaccines, containing different combinations of components of the virus in order to give a broader range of protection. Throughout a period of 48 weeks, the volunteers received 4 doses of different “mosaic” vaccines. An anti-HIV immune response was seen in 100% of individuals.
The only effective way to medically prevent the spread of HIV is the prophylactic drug PrEP, which needs to be taken for weeks before exposure, as well as daily to maintain its protective effects
A parallel study in rhesus monkeys found that the vaccine provided effective protection from a virus similar to HIV in 67% of the 72 monkeys. This level of protection previously unseen in attempts at HIV vaccine development.
Professor Dan Barouch of Harvard Medical School, lead author of the study, describes the results as an “important milestone” in HIV research, but advises that the findings be “interpreted with caution”. Professor Barouch warns that the ability of the vaccine to produce an immune response to the virus may not directly translate into protection from infection. It is also vital to acknowledge that the presence of a link between protection from HIV in rhesus monkeys and protection in humans is also unproven.
The ability of the vaccine to produce an immune response to the virus may not directly translate into protection from infection
Despite this, the vaccine will continue on to be tested on 2600 women in southern Africa, who are at risk of contracting HIV. This next stage aims to determine how effective this vaccine might be at protecting humans from HIV infection.
These encouraging results represent the very first stage of the long journey towards creating a vaccine able to control the spread of HIV. Time will tell if this vaccine will play an important role in the management of this notorious infection in the future, but in the meantime, we will continue to rely on established methods such as contraception and prophylactic medications.