Thursday October 18, 2018

A One-Shot Nanoparticle Vaccine for Polio is Developed by MIT scientists

A novel single-shot nanoparticle vaccine developed by MIT researchers could assist efforts to eradicate polio worldwide. Currently, two to four polio vaccine injections are required to build up immunity, and because of the difficulty in reaching children in remote areas, the disease still prevails.

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A novel single-shot nanoparticle vaccine developed by MIT researchers could assist efforts to eradicate polio worldwide.

Currently, two to four polio vaccine injections are required to build up immunity, and because of the difficulty in reaching children in remote areas, the disease still prevails.

The novel vaccine delivers multiple doses in just one injection to prevent the paralysis caused by the polio virus.

“Having a one-shot vaccine that can elicit full protection could be very valuable in being able to achieve eradication,” said Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research in Cambridge, US.

“Children in some of these hard-to-reach developing world locations tend to not get the full series of shots necessary for protection. The goal is to ensure that everyone globally is immunized,” Jaklenec added, in a paper appearing in the journal Proceedings of the National Academy of Sciences.

To create a single-injection vaccine, the team encapsulated the inactivated polio vaccine in a biodegradable polymer known as PLGA.

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An Afghan child looks on as a health worker administers polio vaccine .

This polymer can be designed to degrade after a certain period of time, allowing the researchers to control when the vaccine is released.

The researchers designed particles that would deliver an initial burst at the time of injection, followed by a second release about 25 days later.

They injected the particles into rats, and found that the blood samples from rats immunised with the single-injection particle vaccine had an antibody response against polio virus just as strong as, or stronger than, antibodies from rats that received two injections of Salk polio vaccine — the first polio vaccine, developed in the 1950s.

Furthermore, the researchers said that they could design vaccines that deliver more than two doses, each a month apart and hope to soon be able to test the vaccines in clinical trials.

Also Read: Parents More Worried About the Vaccines Rather Than the Disease

They are also working to apply this approach to create stable, single-injection vaccines for other viruses such as Ebola and HIV. (IANS)

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Will Polio Workers Step Out of Their Comfort Zones to End Virus?

What's more, the border between Afghanistan and Pakistan stretches for more than 2,000 kilometers. Thousands of people who cross this very porous border can easily transmit the virus in both countries.

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Widespread unrest in Afghanistan has kept thousands of children from receiving polio vaccines this year. Conflict in northern Nigeria does the same. VOA

The move to end Polio started in 1985 with Rotary International. At that time, polio paralyzed hundreds of thousands of children every year. There is still no cure, but two scientists developed vaccines against the virus in the 1950’s.

Dr. Jonas Salk produced one with an inactivated virus that could protect against polio without spreading the disease. Later, Dr. Albert Sabin developed an oral vaccine with weakened strains of the virus.

In 1988, public and private groups joined the effort in the Global Polio Eradication Program. Members included governments, the World Health Organization, the United Nations Children’s Fund (UNICEF), Rotary International, the U.S. Centers for Disease Control and Prevention (CDC) and the Bill and Melinda Gates Foundation.

Since then, the number of polio cases has dropped by 99.9 percent. Last year, 22 children were crippled by this disease. The wild polio virus exists in only three countries: Pakistan, Afghanistan and Nigeria, but it’s still a global threat.

Dr. John Vertefeuille, from the CDC said, “This last mile is a complicated mile.” It’s not just because of conflict or terrorism. “It’s extreme remoteness. It’s very fragile health systems.” And in these remote conflict prone areas gaining access to children can be a major problem.

If polio exists anywhere, it can once again spread everywhere.

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In many places the vaccinators are women because women can go into the homes, talk to other women and gain access to the children. Wikimedia

Vertefeuille and other experts discussed strategies to realize a polio-free world July 10 at the Center for Strategic and International Studies in Washington.

Widespread unrest in Afghanistan has kept thousands of children from receiving polio vaccines this year. Conflict in northern Nigeria does the same.

What’s more, the border between Afghanistan and Pakistan stretches for more than 2,000 kilometers. Thousands of people who cross this very porous border can easily transmit the virus in both countries.

While the funding and technical support has to come from large, private-public partnerships, immunization teams succeed best if they are local. Approaches have to take culture and customs into consideration.

In many places the vaccinators are women because women can go into the homes, talk to other women and gain access to the children.

Elsewhere, soldiers vaccinate children when they take over an area run by anti-government forces. Vaccination teams have to be prepared to move quickly when there is a lull in the fighting and to deliver multiple doses of vaccine in a short period of time.

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Community volunteers are a great resource. Some get cell phones so they can alert health officials if a child becomes paralyzed. VOA

Surveillance is just as critical. To end polio, you have to know where the outbreaks are. Community volunteers are a great resource. Some get cell phones so they can alert health officials if a child becomes paralyzed.

Another challenge is getting children in migrant groups vaccinated. Vertefeuille says this is where technology helps. The CDC uses satellites to see where people have moved and what areas are abandoned. Clues are where structures have been repaired, where the grass grows on roads, indicating abandoned areas, and where it doesn’t, indicating where people are living.

Dr. Andrew Etsana from the International Federation of Red Cross and Red Crescent Societies said these groups present a particular challenge because “you have people moving with a virus and it is difficult to track them and vaccinate the vulnerable children in this mobile population.”

Another issue is the nature of viruses themselves. Viruses mutate. So far, the polio vaccines have been effective, but if not enough children get vaccinated, the virus can change, and perhaps make the vaccine less effective. That’s why every child needs to be vaccinated.

Outbreaks that can be avoided by vaccinating the whole population so that there are no gaps for the mutated virus to slip through.

International experts are working with local leaders to close this gap.

Another issue is complacency. Etsana said, “People are getting tired. The program has been going on. They thought it would have ended.”

Rotary has pledged to continue its support, other groups as well. International support and funding is critical to ending polio, but after three decades, many people have never seen polio. Etsana says he sees complacency creeping into all areas of the program. “The funders of the program are also getting tired. The fund is drying up and if the fund dries up and the job is not done, we’re going to have a major problem. We may have reinfection.”

Also Read-After Three Years Struggle, WHO Declares Somalia Polio Free

But, if people recognize the program’s value – it has united communities, established vaccine centers, created partnerships never before imagined – the world can not only end polio, but tackle other diseases as well. The polio program is widely credited with stopping the spread of Ebola in Nigeria while the disease ravaged other west African countries. (VOA)