The HIV vaccine developed by the Johnson & Johnson laboratory did not provide adequate protection against the disease, announced the company and US health authorities on Tuesday (31). Although the vaccine did not cause serious side effects, its effectiveness in preventing HIV infection was just over 25%.
The vaccine’s low efficacy was evidenced after the Imbokodo clinical trial, conducted in young women from five countries in sub-Saharan Africa.
“Despite our disappointment that the vaccine candidate did not provide a sufficient level of protection against HIV infection in the Imbokodo trial, the study will provide important scientific discoveries in the ongoing search for a vaccine to prevent HIV,” said Paul Stoffels, scientific director of the Johnson & Johnson.
Despite the unsatisfactory result, the laboratory is leading another parallel trial for an HIV vaccine, this time focusing on men who have sex with men and transgender individuals (people who identify with a gender other than their biological sex).
Scheduled for completion in March 2024, this study is being conducted in the Americas and Europe, where the strain of the virus differs from that prevalent in Africa.
Understand how HIV vaccine research works
To reach this conclusion, the laboratory conducted clinical trial tests with approximately 2,600 women between 18 and 35 years old from five countries in sub-Saharan Africa (Malawi, Mozambique, South Africa, Zambia and Zimbabwe).
The researchers decided to assess the immune response generated by the vaccine against HIV infection in sub-Saharan African countries because, in the region, women and girls represented the highest percentage of new cases. In 2020, they accounted for 63% of new HIV infections.
To assess the vaccine’s effectiveness, the women were divided into two groups: one that would receive four injections of the vaccine over a year and the other, placebo.
Two years after the first injection, 51 of the 1,079 participants who received the vaccine contracted HIV. Among participants who received placebo (1,109), 63 women contracted the virus.
Clinical trials began in 2017, but only now, after the release of the vaccine results, will participants be informed whether they received the immunizing agent or placebo.
Johnson & Johnson’s vaccine uses “viral vector” technology – the same one used in the production of its Covid-19 vaccine.
The vaccine uses a common type of virus, called adenovirus, which is modified to make it harmless and capable of carrying genetic information that allows the body to fight the target virus – in this case, HIV.
Johnson & Johnson is not alone in the race to develop an HIV vaccine. According to a US government website, the Moderna biotechnology laboratory is expected to begin testing two HIV vaccines in September this year.
The vaccines developed by Moderna use messenger RNA technology – the same used by the company in its vaccine against Covid-19.