Vaccine research struggles to find trial participants

South African HIV vaccine research efforts are being threatened by the low number of people willing to participate in trials, said the Medical Research Council (MRC). According to researchers from the MRC in the port city of Durban, the fear of stigma and discrimination from their communities prevented people from taking part in the trials. The country began conducting vaccine trials in November 2003. The stringent eligibility criteria also saw many potential study participants being rejected. Although more than 400 people have attended the MRC's HIV vaccine information sessions in the past two years, only 90 have returned for the screening process - a medical check-up that establishes eligibility. Of these 90, only 18 have been enrolled in Phase I vaccine trials. The MRC has managed to find a further 30 eligible candidates during the past twelve months. Eighteen volunteers is the minimum amount required to proceed with the trials at the Durban site, as the first phase needs a small number of participants. But the vaccine trials could be at risk if the existing participants drop out. The MRC's HIV Vaccine Research Unit, based in Durban and the Perinatal HIV Research Unit at the Chris Hani Baragwanath Hospital in Soweto, Johannesburg are the only two trial sites. Two more sites are expected to start vaccine testing in the next few months. Despite ongoing education campaigns, misconceptions and myths about the trials and the vaccine present another obstacle. A large number of people believed they could be infected with the HI virus by being inoculated with a test vaccine, researchers said. Such fears were unfounded, "as no live viruses are injected," explained MRC senior clinical research nurse Armstrong Makhofola. "The replicating parts of the virus are removed, so that the virus is like a car without a motor." Dr Andrew Robinson, head of the MRC HIV Vaccine Unit, said: "At no stage is any participant exposed to infection through the vaccine. Only copies of small fragments of the virus are used in the vaccine." The stigma associated with joining an HIV vaccine trial remains the biggest challenge. Lebo Mthembu from Glenmore in Durban decided to become involved in vaccine research after her younger sister died from an AIDS-related illness in 1998 but, once her community discovered she was participating in HIV vaccine trials, she was discriminated against and many suspected her to be HIV-positive, she told PlusNews. Many willing volunteers also do not meet the stringent eligibility criteria, such as belonging to a certain age group, being in good health, having a good level of education, being HIV-negative and at low risk of contracting HIV, as well as not planning a pregnancy in the near future, said Makhofola. Phase I trials in Durban and Soweto will end in mid-2005. These results will dictate whether the research can move into its second and third phases, explained Robinson. If all three phases of the trials are successful, South Africa could have an effective HIV vaccine by 2014. The main objective of Phase I trials is to test the safety of the vaccine prototype. They will also determine its possible side effects. "There could be risks that we are [still] unaware of," Robinson admitted. Despite being in the early stages of the first phase of trials, "so far, the [test] vaccine appears to have strengthened immune response," he said. The candidate-vaccine had also not shown any unexpected side effects so far, Robinson added. The next phase will focus on maintaining the safety level of the vaccine, as well as finding the best dosage and method of administering the vaccine. The third phase involves tens of thousands of participants to assess whether the vaccine prevents natural infection from HIV. A successful HIV vaccine will teach the body to recognise the virus and record the information on how to defeat the virus in the immune system's memory. The vaccine will prevent HIV infection by neutralising the virus with antibodies and a cellular immune response.