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… Babatunde Osotimehin, health minister urges cautious optimism

The world went agog on Thursday last week when news of the discovery of a vaccine for HIV prevention filtered through. However, if previous trials of AIDS vaccines hadn’t been so disappointing, the results that came out on Thursday from the latest trial wouldn’t seem so promising. 
The results aren’t particularly strong, as far as vaccines go — the vaccine combination used in the study won’t be able to stop the spread of HIV around the globe. But, given the history of AIDS vaccine failures, any benefit at all is something worth noting.
For Nigeria and other countries in Africa this breakthrough vaccine discovery may not mean much because the vaccine is based on B and E strains of HIV that most commonly circulate in Thailand not the C strain which predominates in Africa.  
It is estimated that globally 33 million people are infected with the virus. Out of this number, sub-Saharan Africa is said to be home to about 16 million people living with the virus. In Nigeria, officially, 4.4 million Nigerians live with the virus while the prevalence rate is a national average of 4.6 percent though some states have higher rates of infection. The states include Benue, Enugu, Cross River, Rivers, among others.
But it is a landmark development given the several failures of the past in developing an AIDS vaccine. For the first time, an experimental vaccine has prevented infection with the AIDS virus, a watershed event in the deadly epidemic and a surprising result. Recent failures led many scientists to think such a vaccine might never be possible.
The World Health Organisation and the U.N. agency UNAIDS said the results “instilled new hope” in the field of HIV vaccine research.
The vaccine — a combination of two previously unsuccessful vaccines — cut the risk of becoming infected with HIV by more than 31 percent in the world’s largest AIDS vaccine trial of more than 16,000 volunteers in Thailand, researchers announced yesterday in Bangkok.
Even though the benefit is modest, “it’s the first evidence that we could have a safe and effective preventive vaccine,” Jerome Kim said. He helped lead the study for the U.S. Army, which sponsored it with the National Institute of Allergy and Infectious Diseases.
The institute’s director, Anthony Fauci, warned that this is “not the end of the road,” but said he was surprised and very pleased by the outcome.
“It gives me cautious optimism about the possibility of improving this result” and developing a more effective AIDS vaccine, Fauci said. “This is something that we can do.”
The Thailand Ministry of Public Health conducted the study, which used strains of HIV common in Thailand. Whether such a vaccine would work against other strains in the U.S., Africa or elsewhere in the world is unknown, scientists stressed.
Even a marginally helpful vaccine could have a big impact. Every day, 7,500 people worldwide are newly infected with HIV; two million died of AIDS in 2007, UNAIDS estimates.
“Today marks a historic milestone,” said Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, an international group that has worked toward developing a vaccine.
“It will take time and resources to fully analyse and understand the data, but there is little doubt that this finding will energise and redirect the AIDS vaccine field,” he said in a statement.
The study tested the two-vaccine combination in a “prime-boost” approach, in which the first one primes the immune system to attack HIV and the second one strengthens the response.
They are ALVAC, from Sanofi Pasteur, the vaccine division of French drugmaker Sanofi-Aventis; and AIDSVAX, originally developed by VaxGen Inc. and now held by Global Solutions for Infectious Diseases, a nonprofit founded by some former VaxGen employees.
ALVAC uses canarypox, a bird virus altered so it can’t cause human disease, to ferry synthetic versions of three HIV genes into the body. AIDSVAX contains a genetically engineered version of a protein on HIV’s surface. The vaccines are not made from whole virus — dead or alive — and cannot cause HIV.
Neither vaccine in the study prevented HIV infection when tested individually in earlier trials and dozens of scientists had called the new one futile when it began in 2003.
“I really didn’t have high hopes at all that we would see a positive result,” Fauci confessed.
The results proved the skeptics wrong.
“The combination is stronger than each of the individual members,” said the Army’s Kim, a physician who manages the Army’s HIV vaccine program.
The study tested the combo in HIV-negative Thai men and women aged 18 to 30 at average risk of becoming infected. Half received four “priming” doses of ALVAC and two “boost” doses of AIDSVAX over six months. The others received dummy shots. No one knew who got what until the study ended. 
Thanad Yomha, a 33-year-old electrician from southeastern Thailand, said he didn’t expect anything in return for volunteering for the project. 
“I did this for others,” Thanad said. “It’s for the next generation.” 
All were given condoms, counseling and treatment for any sexually transmitted infections, and were tested every six months for HIV. Any who became infected were given free treatment with antiviral medicines. 
Participants were followed for three years after vaccination ended. 
The results: New infections occurred in 51 of the 8,197 given vaccine and in 74 of the 8,198 who received dummy shots. That worked out to a 31 percent lower risk of infection for the vaccine group. Two of the infected participants who received the placebo died. 
The vaccine had no effect on levels of HIV in the blood for those who did become infected. That had been another goal of the study — seeing whether the vaccine could limit damage to the immune system and help keep infected people from developing full-blown AIDS. 
That result is “one of the most important and intriguing findings of this trial,” Fauci said. It suggests that the signs scientists have been using to gauge whether a vaccine was actually giving protection may not be valid. 
“It is conceivable that we haven’t even identified yet” what really shows immunity, which is both “important and humbling” after decades of vaccine research, Fauci said. 
Details of the $105 million study will be given at a vaccine conference in Paris next month. 
This is the third big vaccine trial since 1983, when HIV was identified as the cause of AIDS. In 2007, Merck & Co. stopped a study of its experimental vaccine after seeing it did not prevent HIV infection. Later analysis suggested the vaccine might even raise the risk of infection in certain men. The vaccine itself did not cause infection. 
In 2003, AIDSVAX flunked two large trials — the first late-stage tests of any AIDS vaccine at the time. 
It is unclear whether vaccine makers will seek to license the two-vaccine combo in Thailand. Before the trial began, the U.S. Food and Drug Administration said other studies would be needed before the vaccine could be considered for U.S. licensing. “This is a world first which proves that vaccine development is possible,” said Supachai Rerks-Ngarm, the Thai Health Ministry official who oversaw the trial. “But this is not to the level where we can license or manufacture the vaccine yet.” 
Mass-producing the vaccine, plus how to proceed with future studies, will be discussed among the governments, study sponsors and companies involved in the trial, Kim said. Scientists want to know how long protection will last, whether booster shots will be needed, and whether the vaccine helps prevent infection in gay men and injection drug users, since it was tested mostly in heterosexuals in the Thai trial. 
The study was done in Thailand because U.S. Army scientists did pivotal research in that country when the AIDS epidemic emerged there, isolating virus strains and providing genetic information on them to vaccine makers. The Thai government also strongly supported the idea of doing the study.
The main drawback with the current vaccine is that its 31 percent efficiency is limited to the strain in Asia as already noted with nothing for Africa but it is a significant step forward. It gives hope that in the near future, with more research and funding, this human scourge that has decimated homes and in some cases villages and communities, making orphans out of millions of children in Nigeria and Africa will be tamed. This is also the view of Suleiman Akanmu, consultant haematologist at the Lagos University Teaching Hospital (LUTH), Idi Araba, Lagos, in a telephone interview with BusinessDay on Friday, said the development has raised a situation of hope. “If it works partially, it may work fully. At least it means AIDS vaccine will be a reality one day. If it proves successful for some viral sub-types it may work elsewhere. It is pleasing to the scientific world and all scientists will be working on it now,” he said.
Akanmu added that though the possibility of vaccine development is still far in Nigeria and Africa, there is hope. According to him, if the latest breakthrough is 31 percent effective, it means it can be developed to perhaps 80 percent efficacy with more research. He said no vaccine is 100 percent effective, noting that even the polio vaccine that is generally in use is only 75 percent to 80 percent effective.  
But in his reaction, Niyi Ojuolape, chief press secretary to the health minister, Babatunde Osotimehin, in a telephone interview with BusinessDay, said even though the breakthrough is a good development, Nigerians should exercise caution because it is only a possibility. “The percentage of prevention is too low for us to be happy. We still have to be strong on our prevention messages especially considering that the strain the vaccine can prevent is different from what we have in Nigeria. We have to do a lot to get candidate vaccine; we should not send the wrong message,” he said.