Scientists using vaginal fluids to develop vaccine

Scientists at UoN are using women due to their high predisposition to sexual infections compared to men. [Courtesy]

Scientists at the University of Nairobi are studying the vaginal secretions of volunteers to develop vaccines that stop the HIV virus during intercourse for women only. 

The scientists attached to the Kenya Aids Vaccine Initiative (KAVI) are using women due to their high predisposition to sexual infections compared to men. Their genitalia have a wider surface of interaction with the virus doubling likelihood of infection at 6.6 per cent compared to 3.1 per cent for men.

Cultural restrictions also deny them the right to decide whether or not to have protected intercourse especially in sub-Saharan Africa, says Dr Marianne Mureithi, a scientist at Kavi Institute. “We are swabbing the vaginal walls of those taking part to study the microscopic environment of the landing spots that facilitate viral transmission.”

The other link to higher infections is the use of contraceptives most of which have chemicals that change the vaginal environment and the scientists will thus use mucosal analysis to develop a vaccine that will stop the virus at the point of infection for women.

The study was launched in 2017 and targets both HIV-positive and -negative women from Nairobi’s Kangemi and Kibra areas as well as those who seek hysterectomy services at Kenyatta National Hospital.

Also of interest to the scientists are the cells which interact with the virus during sexual intercourse. They are thus infecting samples of the donated uterus from patients who have undergone hysterectomy with HIV and have noted that cells of the immune system start interacting with HIV virus at the point of entry.

“We want a vaccine that will then stimulate these cells of the immune system to start fighting the virus at that point of entry so that the woman is not infected,” said Dr Mureithi.

Other scientists at the International AIDS Vaccine Initiative (IAVI) have seen promising results from a trial of a vaccine that induces a special type of antibody that can neutralize several HIV variants.

IAVI Medical Director, Dr Vincent Kioi, explained that “one virus responds to a single strain of the virus, but for HIV, because it mutates so much, you end up with a situation where one person who has been infected for a long period of time has so many different variants of the virus within them that their body tries to respond to.”

So far, phase one of the clinical trial produced a 97 per cent desired immune response from volunteers and the next step is to produce a combination of antibodies to combat the different virus variants, says Dr Kioi adding that the antibodies from the vaccine can also be used to fight tuberculosis.