Early data from an HIV vaccine candidate suggest that it stimulates a crucial component of the human immune response in 97 percent of vaccination recipients.
The clinical trial findings, published in the journal Science on World AIDS Day, provide "clinical proof of concept" in favour of designing boosting regimens to generate immune responses against HIV infection, which has no cure and can cause acquired immunodeficiency syndrome, often known as AIDS.
It was a tiny phase 1 study of a vaccine created from an engineered form of a protein found in the HIV virus. This particle was developed to prime the body to produce broadly neutralising antibodies, which are considered to be essential for developing HIV immunity.
Because the HIV virus mutates rapidly, broadly neutralising antibodies would detect a wide range of HIV subtypes, which is required to offer protection.
Forty-eight subjects were given either the vaccine candidate or a placebo, and 35 out of 36 of those given the vaccine candidate demonstrated activation of broadly neutralising antibody precursor B cells, which might result in the first step toward immunisation.
There were no serious side effects reported in the phase 1 study, and other side effects such as pain at the injection site or headaches were mild to moderate and resolved in one to two days.
For almost 40 years, scientists have been attempting to develop an HIV vaccine. This vaccination is notoriously difficult. Part of this is due to HIV's ability to mutate. It can escape the immune system by developing and changing swiftly, making itself difficult to spot.
Furthermore, with the exception of a few high-profile examples, no one has been cured of an HIV infection. That is, we don't know what kind of immune cells exist in the body that can guard against infection.
In theory, this vaccine will be the first in a series of many doses, each of which will use a different HIV particle to educate the immune system. As the injections advance, the molecules become increasingly similar to those of the genuine HIV viruses, until antibodies are created that can bind to many distinct types of HIV.