New Meningitis Strain in Africa Brings Call for More Vaccines


Photo

Somali mothers waiting in line in Mogadishu to have their babies vaccinated against meningitis and other diseases in 2013. Meningitis C infections are on the rise across Africa.

Credit
Ben Curtis/Associated Press

Meningitis may be poised for a ferocious comeback in Africa, international aid organizations are warning, and vaccine manufacturers must step up production if the outbreak is to be averted.

Meningitis is caused by one of several strains of the bacteria Neisseria meningitidis. A vaccine introduced five years ago has all but defeated meningitis A infections in Africa. But infections with another strain, Type C, are on the rise.

Some experts fear the new strain will explode next year, while others say too little is known to predict its course reliably.

Meningitis C vaccines exist but are expensive: $20 per shot is the lowest price offered thus far to an international public health consortium, led by the World Health Organization, that stockpiles vaccines for emergencies.

The consortium, the International Coordinating Group for Vaccine Provision for Epidemic Meningitis Control, is seeking five million doses. To be effective, they must be shipped and injected before January, when meningitis normally returns to Africa with the dry harmattan winds.

Photo

A doctor examining a child in Somalia prior to administering a vaccine. The meningitis C vaccine costs $20 per shot, and millions of doses are said to be needed across Africa.

Credit
Ben Curtis/Associated Press

Unless something drastic happens — a surge of donor money, or huge price cuts — the consortium’s experts do not hold out much hope.

“If we don’t get the doses, we’ll be having a really hard time,” said Dr. William A. Perea, coordinator of the W.H.O.’s epidemic diseases control unit. “So we are making a little noise.”

The global vaccine industry is fragile. Because of mergers and acquisitions, only four major pharmaceutical companies — GlaxoSmithKline, Sanofi-Pasteur, Merck and Pfizer — still make vaccines for diseases other than flu. They are primarily interested in serving wealthy countries, where they can charge $100 or more per dose.

As a result, there are too few factories to supply the vaccines poor countries need, and also little competition to drive down prices.

“Vaccine pricing has traditionally been much more secretive than drug pricing,” said Kate Elder, vaccines policy adviser at Doctors Without Borders. “When we survey companies, they never tell us how they arrive at prices.”

State-owned factories in India, Brazil, Cuba and elsewhere also manufacture meningitis vaccines. While they can sometimes be paid to make more than their own countries need, many are reliant on old technology and hampered by government bureaucracies.

A low-priced vaccine against meningitis C and four other strains of the infection is being developed in India but will need at least another five years of testing.

Meningitis used to strike thousands of Africans every year. In 1997, meningitis sickened 250,000 people and killed 25,000.

Survivors also suffer. A quarter are left brain-damaged, paralyzed, prone to seizures or without limbs that had to be amputated. In African schools for the deaf, most students are meningitis victims.

Desperate families often sell everything to pay for care: chickens, cows, even front doors, which in West Africa can be elaborately carved heirlooms.

Type A bacteria were once responsible for more than 80 percent of Africa’s meningitis cases, but that infection is being vanquished by a new vaccine, MenAfriVac, which was introduced in 2010 by the W.H.O., the Bill & Melinda Gates Foundation and PATH, a Seattle health technology group. Over 220 million doses against Type A, made by the Serum Institute of India for 50 cents each, have been injected.

But that success has had an alarming coda. Two years ago, a new Type C strain appeared, a genetic variant from the previous Type C. In April, a serious outbreak in Niger sickened nearly 6,000 people and caused nearly 500 deaths.

“There was a lot of anxiety, because very few people in Niger didn’t know somebody who’d gotten ill or died in the past,” said Dr. Sarah A. Meyer, an epidemiologist for the Centers for Disease Control and Prevention who helped fight the outbreak. “People prayed for the rains to start. And they started rushing to the pharmacy for vaccines.”

Experts are now fiercely debating what will happen when the harmattan winds return to Africa’s so-called meningitis belt, which stretches from the Atlantic Coast to Ethiopia.

Photo

A Somali baby receiving a vaccination in 2013. Only four major pharmaceutical companies still make vaccines for diseases other than flu.

Credit
Ben Curtis/Associated Press

Experts at the W.H.O. and Doctors Without Borders fear that the new strain will spread. But others, including Dr. Meyer and colleagues at the C.D.C., say there is no way to predict that with confidence. Previous outbreaks of meningitis C — in Europe, for example — have not followed the pattern typical of Type A in Africa: a few low-level years, then an explosive epidemic.

“The idea that there is a death knell sounding for these countries is exaggerated,” said Dr. Marc LaForce, a meningitis expert who led the development of MenAfriVac.

But the new Type C strain is not identical to its European ancestor, “so one has to prepare,” said Dr. Olivier Ronveaux, an epidemiologist at the W.H.O.

Over the next few weeks, his agency hopes to swab the throats of Africans across the belt to see how many carry the new Type C strain without symptoms. That may help predict what will happen in January.

On a much smaller scale, a similar strain substitution took place on American college campuses in the last decade. Expensive new quadrivalent vaccines, effective against multiple strains of meningitis, were introduced in 2005 and reduced infections with Types A, C, W and Y by more than 90 percent.

Then, in 2013, the B strain surged, causing outbreaks at Princeton and the University of California, Santa Barbara. One student died. The Obama administration responded by importing a meningitis B vaccine that had been approved in Europe but not in the United States.

Meningitis often strikes young people and can progress from a bad headache to death so quickly that hospital care comes too late, even in the United States.

Mysteriously, Neisseria bacteria spread easily in saliva and harmlessly colonize the throats of about a fifth of the world’s population. The bacteria kill only if they reach the bloodstream or the meninges, membranes protecting the brain and spine.

In the West, “freshman meningitis” or “boot camp meningitis” affects people gathered in dorms or barracks who adopt new habits like sharing beer bottles, toothbrushes, cigarettes or joints — or kissing.

In Africa, meningitis surges when cold winds force families indoors and dry out throats, opening tiny cracks through which bacteria enter the blood.

The world used to rely on polysaccharide vaccines, which are cheap, but their protection does not last long, and they do not kill silent throat infections.

About 20 years ago, conjugate vaccines were introduced. By coupling the polysaccharides — sugarlike molecules from the bacterial membranes — to proteins, they provoke long-lasting immune responses and can also clear silent infections.

Six strains of the meningitis bacteria — A, B, C, W, X and Y — cause disease. GlaxoSmithKline and Sanofi make conjugate vaccines against A, C, W and Y, and have made some of them available to the W.H.O. at lower prices. But the manufacturers cannot produce enough for a major outbreak.

The Serum Institute of India is working on a vaccine against five strains — all but B — but it will not be finished until about 2020, Dr. LaForce said, assuming it passes all clinical trials.

Vaccines against Type B bacteria must be made differently because the polysaccharides on the membrane of that strain resemble some on the surface of human nerve cells, so there is a risk that making antibodies to them could cause a dangerous autoimmune reaction.



Source link

About admin

Check Also

Senate, Zimbabwe, Ross 128: Your Wednesday Evening Briefing

At the White House, President Trump went on TV to declare his trip to Asia ...

Leave a Reply

Your email address will not be published. Required fields are marked *