JOHANNESBURG — For over a century, epidemics of bacterial meningitis have swept across Africa, arriving with the dry harmattan winds to kill with terrifying speed. But on Dec. 6, a drive starts to inoculate tens of millions of West Africans with a new vaccine in what scientists hope will be the beginning of the end of ravaging meningitis epidemics.
The aim is for these immunization campaigns to spread from Senegal in the west to Ethiopia in the east, bringing the disease under control and saving an estimated 150,000 lives by 2015 in a belt of 25 nations that girds the continent.
Hundreds of millions of dollars are still needed to accomplish that goal, public health officials say. But the meningitis vaccine itself is a milestone in developing inexpensive vaccines against neglected diseases that afflict poor countries, experts say.
More than a million cases of meningitis have been reported in Africa over the past two decades, and the vaccine works against the group A meningitis strain that causes more than 8 out of 10 cases on the continent. Moreover, it costs less than 50 cents a dose. In the United States, Novartis and Sanofi Pasteur market a single dose of meningitis vaccines against multiple strains of the disease for $80 to $100.
“Wow, that’s remarkable!” exclaimed Dr. Gregory A. Poland, head of vaccine research at the Mayo Clinic in Minnesota, when he heard how little the new vaccine would cost.
Bill Gates, whose foundation largely financed the endeavor, contrasted the undertaking with the development of vaccines for measles, smallpox and polio.
“All those things were created because rich people got sick,” he said in an interview. “This is the first vaccine that went through the whole process where there was no rich world market, and it had to be optimized at a very low price.”
The meningitis vaccine relies on a technology that was devised by researchers at the Food and Drug Administration and donated by the United States government at the cost of only token royalties. It is being manufactured by the Serum Institute of India, a major vaccine producer, and it was developed independently of the major American and European pharmaceutical companies.
“Doing this outside of big pharma and developing the vaccine explicitly for the developing world is very innovative,” said Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt Medical School, who, like Dr. Poland, was not involved in developing the meningitis vaccine. “There’s nothing else like it.”
This model of vaccine development probably will not work to develop the first vaccines for complex diseases like AIDS and malaria, in which basic scientific breakthroughs are still necessary, experts said. But researchers are already working on efforts similar to the one for meningitis to produce inexpensive vaccines for cholera, pneumonia and rotavirus, a diarrheal disease.
The meningitis vaccination drives begin Monday in Burkina Faso and will get under way in Mali and Niger this month, but public health experts cautioned that the promise of the meningitis vaccine should not be oversold. It will not eradicate the disease because it is effective only against the group A strain most common in Africa.
“Almost certainly, you’ll see other serotypes start to infect people,” Dr. Poland said. But he said the vaccine, if used broadly, would solve the most pressing immediate problem: epidemics of the group A type.
The development of the vaccine was led by a team from Path, a nonprofit group in Seattle, and the World Health Organization. They coordinated contributions from nonprofit, public and for-profit parties. In June, after five years of clinical trials in West Africa and India, the World Health Organization approved the vaccine for use on a large scale.
“These product development efforts are very expensive,” said Doug Holtzman, deputy director of infectious diseases at the Bill and Melinda Gates Foundation. “This one is a bargain. For less than $100 million, a vaccine was developed from scratch and licensed, though the technological path had already been marked before.”
So far, donors and African countries have raised $95 million of the estimated $570 million cost of eliminating meningitis epidemics across Africa, W.H.O. officials say. But the global financial crisis has pinched foreign aid spending, leaving the remainder in doubt.
“I’m extremely worried,” Mr. Gates said. “You have one of the simplest, most effective interventions ever invented being limited by how much money you have, rather than country demand or regulatory problems.”
The push to find an effective new vaccine began after a meningitis epidemic in 1996 and 1997 infected more than a quarter million Africans, killed 25,000 and disabled 50,000. Richard Adegbola was a medical researcher in Gambia then and described hospitals overwhelmed with panicky patients.
“It was confusion and chaos,” said Mr. Adegbola, a microbiologist who now works at the Gates Foundation.
Bacterial meningitis is a highly contagious infection of the lining around the brain and spinal cord. People catch it by sharing eating utensils or cigarettes, by kissing, or by sneezing or coughing on each other.
The symptoms include fever, chills, headaches and a stiff neck. Within a day or two, it kills about one in 10 of the people who get it, even if they are swiftly treated with antibiotics. Up to a fifth of survivors suffer permanent disabilities, most commonly deafness, cerebral palsy, mental retardation and epilepsy.
Until the development of the new vaccine, public health officials had to rely on a far less effective polysaccharide vaccine that protected people only for two to three years and did not prevent transmission of the bacteria. As a result, it was used only to rein in an outbreak after it had occurred. Often, by the time supplies arrived, many people had already died.
In contrast, the new conjugate vaccine, which links the sugar in the vaccine with a protein, produces a more powerful immunity that experts hope will last 10 to 20 years. It also prevents transmission, helping protect people who have not been vaccinated and producing what is known as herd immunity. The plan is to vaccinate 300 million people across 25 nations, protecting about half a billion people from the disease, W.H.O. officials said.
Dr. F. Marc LaForce, who has led the effort, known as the Meningitis Vaccine Project, since its inception in 2001, said scientists still did not understand why the advent of the dry season brought meningitis.
“No one knows,” he said. “But if we are taking care of the problem without knowing exactly why it works, I don’t care. I’ll be satisfied. I want this disease to go away.”
Monday, December 6, 2010
The NY Times:
Posted by BA Haller at 11:07 AM