An experimental vaccine against HIV, the virus that causes AIDS, had its studies ended after data showed that the protection offered by the immunizing agent to the body was insufficient. Manufactured by Johnson & Johnson, the vaccine was only 25% effective.
“I should be used to it by now, but you never are. You still put your heart and soul into it,” the study’s lead researcher and chair of the South Africa Medical Research Council, Glenda Gray, told the New York Times. The researcher has been trying to develop a vaccine for the virus for over 15 years.
The study, called Imbokodo, analyzed 2,600 young women, aged between 18 and 35, from five countries in sub-Saharan Africa (Malawi, Mozambique, South Africa, Zambia and Zimbabwe). The region chosen was decisive in the study, as it represents the largest share of vulnerable women across the continent, accounting for nearly two-thirds of new HIV infections in 2020.
Testing began in 2017. Since then, the participants have received four doses of the immunizing agent over the period and have been monitored by the team of researchers. In two years of observation, 51 of the 1,079 participants who received the vaccine became infected; among the 1,109 volunteers who received placebo, 63 contracted the virus. The technology used in the immunization is the inactivated adenovirus, as well as the AstraZeneca, Janssen and Sputnik V vaccines against Covid-19.
Despite the low efficacy, the study provided some useful data. Recent research in Thailand has indicated that antibodies caused by the vaccine may be sufficient to provide protection against the virus at an early stage of infection. This means, according to Glenda, that the fact that the study was conducted in Africa, where HIV incidence rates are higher, may have been a determining factor in the result.
“The type of immune response induced was not enough to stop the high attack rates that we see in Africa”, says the researcher.
A parallel work, called Mosaico, must still proceed, according to the manufacturer. Another immunizer is currently being tested in eight countries, including Brazil, in men who have sex with men and transgender people.
The Mosaic is a joint public-private effort involving the US National Institutes of Health (NIH), the HIV Vaccine Trials Network, based at the Fred Hutchinson Cancer Research Center, the Medical Research and Development Command of the US Army and Johnson & Johnson pharmaceutical Janssen.
Moderna, which is also one of the makers of a vaccine against Sars-CoV-2, recently announced that it will begin testing a new immunizer against HIV. According to the company, the tests should start this year.
According to data from the World Health Organization (WHO), about 38 million people are living with HIV worldwide; 1.5 million infected in the last year.
With information from international agencies.