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An Experimental Vaccine to Treat Malaria

Scientists hope to get a better grasp on the system these vaccines employ, known as cellular immunity. Harnessing this system could help tackle hepatitis and HIV infection.

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A doctor assists people looking for treatment for malaria at a health center in San Felix, Venezuela. VOA
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After decades of disappointment in efforts to develop a malaria vaccine, researchers are starting to see promise in a new approach.

While most vaccines trigger the body’s defenses to produce antibodies against a disease-causing germ, the new approach recruits an entirely different branch of the immune system.

If it works, it could open up a new route to attack other diseases, including hepatitis and possibly HIV, the virus that causes AIDS.

Nearly 450,000 people die of malaria each year, according to the World Health Organization. The parasites that cause the disease are increasingly becoming drug-resistant.

One successful vaccine has been developed so far, but it prevented only about a third of cases in a clinical study.

Experts have decided that’s better than nothing. The vaccine is being piloted in Ghana, Kenya and Malawi.

Vaccine
Defensive cells killed liver cells that were infected with malaria parasites. (VOA)

New angle

Other scientists are trying a different angle of attack.

There are basically two ways to prevent germs from causing infections. “You either prevent them from getting into cells with antibodies, or you kill them inside the cells with T-cells,” said Stephen Hoffman, chief executive officer of Sanaria, a company working on one vaccine.

Most vaccines target the infection by building up antibodies. “If you need to kill them inside the cells with T-cells, we haven’t been overwhelmingly successful,” Hoffman said.

But Sanaria is one group seeing success by targeting malaria parasites inside infected liver cells, the first stop in the complex life cycle of the disease.

One key difference is how the vaccine is delivered. Hoffman’s group tried a typical route: injecting radiation-weakened parasites into patients’ skin or muscle. That didn’t work.

But it did work when injected directly into veins.

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A public health worker takes a blood sample from a woman to be tested for malaria in Bo Rai district, Trat province, Thailand. VOA

The weakened parasites traveled to the liver, where they set off an immune reaction. Defensive cells killed liver cells that were infected with malaria parasites.

And the liver’s defenses were ready when faced with the real thing months later.

Most of that early work has been done in mice and macaques. When Hoffman and colleagues did something similar with a handful of human patients, most were protected against infection.

No waiting

Recruiting immune cells in the liver is especially effective because “we don’t need to wait until the immune system figures out that the parasite is in the liver and starts mounting an immune response, which can take days and sometimes weeks,” said Adrian Hill, director of the Jenner Institute at Oxford University.

“By then, the malaria’s gone. It only spends a week in the liver, and then it’s out in your blood causing disease.”

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FILE – A worker of the Ministry of Public Health and Population fumigates in the street against mosquito breeding to prevent diseases such as malaria, dengue and Zika in Port-au-Prince, Haiti, Feb. 15, 2016. VOA

Hill’s group just published a study in the journal Science Translational Medicinein which immune cells in the liver were triggered by using a protein from the parasite, rather than the entire organism.

Scientists hope to get a better grasp on the system these vaccines employ, known as cellular immunity. Harnessing this system could help tackle hepatitis and HIV infection.

Also Read: Alcohol Kills More People Than AIDS, Violence Combines: WHO

Drugs can control HIV infection but can’t eliminate it from the body.

“If somebody could get cellular immunity to work really well for vaccination, that would be transformative for a whole range of diseases,” Hill said. “Not just for infectious diseases that we want to prevent, but ones that we want to treat and we can’t treat today.” (VOA)

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Women Hit Especially Hard In Congo’s Worst Ebola Outbreak

For the afflicted, the road to recovery is long and lonely.

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Congolese health workers register people and take their temperatures before they are vaccinated against Ebola in the village of Mangina in North Kivu province of the Democratic Republic of Congo. VOA

The Democratic Republic of Congo is in the throes of its worst-ever Ebola outbreak, with more than 420 cases in the country’s volatile east, and a mortality rate of just under 60 percent. But this outbreak — the nation’s tenth known Ebola epidemic — is unusual because more than 60 percent of patients are women.

Among them is Baby Benedicte. Her short life has already been unimaginably difficult.

At one month old, she is underweight, at 2.9 kilograms. And she is alone. Her mother had Ebola, and died giving birth to her. She’s spent the last three weeks of her life in a plastic isolation cube, cut off from most human contact. She developed a fever at eight days old and was transferred to this hospital in Beni, a town of some half-million people in the east of the Democratic Republic of Congo.

More than 400 people have been diagnosed with Ebola here since the beginning of August, and more than half of them have died in a nation the size of Western Europe that struggles with insecurity and a lack of the most basic infrastructure and services. That makes this the second-worst Ebola outbreak in history, after the hemorrhagic fever killed more than 11,000 people in West Africa between 2013 and 2016.

This is 10th outbreak to strike the vast country since 1976, when Ebola was first identified in Congo. And this particular outbreak is further complicated by a simmering civil conflict that has plagued this region for more than two decades.

Guido Cornale, UNICEF’s coordinator in the region, says the scope of this outbreak is clear.

“It has become the worst outbreak in Congo, this is not a mystery,” he said.

What is mysterious, however, is the demographics of this outbreak. This time, more than 60 percent of cases are women, says the government’s regional health coordinator, Ndjoloko Tambwe Bathe.

“All the analyses show that this epidemic is feminized. Figures like this are alarming. It’s true that the female cases are more numerous than the male cases,” he said.

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Health workers walk with a boy suspected of having been infected with the Ebola virus, at an Ebola treatment center in Beni, near Congo’s border with Uganda. VOA

Bathe declined to predict when the outbreak might end, though international officials have said it may last another six months. Epidemiologists are still studying why this epidemic is so skewed toward women and children, Cornale said.

“So now we can only guess. And one of the guesses is that woman are the caretakers of sick people at home. So if a family member got sick, who is taking care of him or her? Normally, a woman,” he said.

Or a nurse. Many of those affected are health workers, who are on the front line of battling this epidemic. Nurse Guilaine Mulindwa Masika, spent 16 days in care after a patient transmitted the virus to her. She says it was the fight of her life.

“The pain was enormous, the pain was constant,” she said. “The headache, the diarrhea, the vomiting, and the weakness — it was very, very bad.”

Congo, Ebola, Women
Marie-Roseline Darnycka Belizaire, World Health Organization (WHO) Epidemiology Team Lead, talks to women as part of Ebola contact tracing, in Mangina, Democratic Republic of Congo. VOA

For the afflicted, the road to recovery is long and lonely. Masika and her cured colleagues face weeks of leave from work to ensure the risk of infection is gone. In the main hospital in the city of Beni, families who have recovered live together in a large white tent, kept four meters from human contact by a bright orange plastic cordon. They yell hello at their caretakers, who must don protective gear if they want to get any closer.

And for Baby Benedicte, who is tended to constantly by a nurse covered head to toe in protective gear, the future is uncertain. Medical workers aren’t entirely sure where her father is, or if he is going to come for her.

Also Read: Congo Start Trials For Drugs Against Ebola

She sleeps most of the day, the nurse says, untroubled by the goings-on around her. Meanwhile, the death toll rises. (VOA)