New Vaccine May Help Eradicate Polio

Scientists have identified new ways to provide vaccines against polio, which do not require the growth of live virus for their manufacture.

Researchers at the University of Leeds have successfully modified virus-like particles to adapt them in creating a new polio vaccine.

Despite the success of vaccines produced from 'virus-like particles' (VLPs) for hepatitis B and human papilloma viruses, poliovirus VLPs, also known as 'empty capsids’, have proved to be unstable to make practical vaccines.

These empty capsids change shape when warmed and become unusable as vaccines, but the mutations identified in this research prevent these damaging changes.

These new stabilised VLPs are suitable as replacements for the current killed poliovirus vaccines and can be produced in ways that do not require the growth of live virus.

Polio has been nearly eradicated worldwide.

However, governments will need to continue to create vaccines to prevent it from recurring.

Polio used to be very common in the United States and caused severe illness in thousands of people each year before polio vaccine was introduced in 1955. Most people infected with the polio virus have no symptoms, however for the less than one percent who develop paralysis (cannot move arms or legs) it may result in permanent disability and even death.

There are two types of vaccine that protect against polio: Inactivated Polio Vaccine (IPV) and Oral Polio Vaccine (OPV). IPV, used in the United States since 2000, is given as an injection in the leg or arm, depending on age. OPV is taken by mouth.

Polio vaccines may be given at the same time as other vaccines. CDC vaccine price list can be found here.

The Leeds team and collaborators say this form of vaccine, using the newly developed stabilised VLPs, would be best used after the virus has been eradicated.

"Continuing to vaccinate after polio has been eradicated is essential to ensure against the disease recurring, but there are significant biosafety concerns about current production methods," David Rowlands, professor of Molecular Virology at the University of Leeds and co-author of the study.

"Our new method of creating the vaccine has been proven to work in lab conditions and on top of that we've proved it's actually more stable than existing vaccines."

According to the CDC, all children should receive four doses of IPV at ages 2 months, 4 months, 6-18 months, and at 4-6 years. The minimum interval between the third and fourth doses should be 6 months.

The global switch from tOPV to bOPV will markedly reduce the risk for type 2 cVDPV reemergence and possible importation into the United States.

However, until this risk is estimated by WHO to approach zero, public health authorities in the United States should continue to follow CDC recommendations regarding poliovirus vaccination to ensure that all children living in the United States are protected against all three poliovirus types.

Professor Nicola Stonehouse, co-leader of the study, from the University of Leeds said: "The international drive to eradicate polio using existing vaccines continues, but methods need to be found to maintain vaccination safely as insurance after it appears to have been eradicated. This is when our approach will come into its own.”

Authors reported no conflicts of interest: Oluwapelumi O. Adeyemi, Clare Nicol, Nicola J. Stonehouse and David J. Rowlands. Affiliations: School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom