A step forward in the fight to defeat rotavirus

October 10, 2019 by PATH

A new type of rotavirus vaccine may protect even more kids from rotavirus and the severe and deadly dehydration it can cause.

A healthcare worker in Kenya prepares a routine immunization. PATH/Wendy Stone

Health worker Gladys Wambu fills a syringe from a vaccine vial. Health workers like Gladys will play a critical role in delivering rotavirus vaccines to the children who need them most. PATH/Wendy Stone

Rotavirus vaccines are lifesavers. Since they first became available, rotavirus disease in young children has declined dramatically, particularly among infants less than a year of age. Countries around the globe have seen dramatic reductions in rotavirus deaths and hospitalizations following vaccine introduction, and nearly 100 countries have introduced rotavirus vaccines into their routine childhood immunization programs so far.

Yet, even with all the progress we’ve made, rotavirus still remains the leading cause of diarrheal disease, responsible for an estimated 215,000 deaths every year among children under 5. While nearly every child is at risk of rotavirus infection regardless of where they live, 90 percent of rotavirus deaths occur in low- and middle-income countries. A more affordable vaccine that works even better in high-burden populations could drastically reduce rotavirus diarrhea and increase access in the places where the disease takes the largest toll.

A more affordable vaccine that works even better in high-burden populations could increase access and drastically reduce rotavirus diarrhea.

A new approach

While the currently available live, oral rotavirus vaccines are safe, effective, and making a huge impact where they have been introduced, they don’t perform as well in the countries that need them the most. Data suggest that the efficacy for these vaccines is around 50 percent in Asian and African countries that experience the highest burden, compared to upwards of 85 percent in places like the United States and Western Europe. Yet it is precisely these children in high burden areas—who are most at risk for severe disease and most likely to be without access to the urgent medical treatment required to care for them should they fall sick—that depend on the lifesaving protection from rotavirus vaccines most of all. We want to protect all children, which is why we’ve been working on developing a new type of rotavirus vaccine, called a non-replicating rotavirus vaccine (NRRV), that may work even better for children in Africa and Asia.

Unlike the oral vaccines, NRRVs are given by injection, potentially overcoming the factors scientists think are responsible for the lower efficacy seen in high-burden settings by bypassing the child’s gut. Our hope is that this approach will provide superior protection to children in these settings, who are the most vulnerable to the devastating consequences of rotavirus.

A promising step forward

To answer this question, we are evaluating an NRRV candidate, called trivalent P2-VP8, in a Phase 3 clinical study to determine if it protects infants in African and Asian settings from severe rotavirus disease. This pivotal study, which is being conducted with partners in Zambia, Ghana, Malawi, and India, will provide us with key data on vaccine efficacy and safety in the parts of the world where rotavirus hits hardest. Once completed, we will know how well the study vaccine works to prevent rotavirus compared to a licensed oral vaccine. This study is an important step before the vaccine can be licensed and made available to the communities that need it the most. Additionally, through the efforts of our commercial partner SK bioscience to optimize the manufacturing process, the vaccine candidate is expected to be even more affordable than the currently available oral rotavirus vaccines, potentially facilitating uptake and freeing up funds for other health priorities. If successful, this vaccine could be a new game-changing tool in our arsenal to defeat rotavirus, potentially saving many more lives and letting kids grow up healthy and strong so that they can reach their full potential.

If successful, this new vaccine could be a game-changing tool in our arsenal to defeat rotavirus.

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