New polio vaccine against strains threatening safe disease eradication: Lancet

Polio is a highly infectious viral disease that affects children under the age of five and causes paralysis in every 200 infections. (File photo)

Scientists have developed the first poliovirus vaccine against variants of the disease that are causing the outbreak in Africa and Asia. The new vaccine, known as nOPV2, targets poliovirus type 2, has improved genetic stability, and is less likely to mutate back to a form of virus that can cause infection or paralytic disease. It has become.

According to a new study published in two The Lancet papers, the new vaccine appears to be as safe as tested in healthy adults, children and babies and provide a similar immune response. Based on the results of these Phase 2 clinical trials, the nOPV2 vaccine has been recommended by the WHO on the Emergency Use List (EUL) and is the first vaccine to follow this route for global health emergencies. It has become.

The current objective is to use vaccines to combat the increasing outbreak of vaccine-derived poliovirus in Africa, as well as in Afghanistan, Pakistan, the Philippines, Malaysia, and other countries. We are currently working on the outbreak using the original Sabin oral vaccine for type 2 polio. In a new study published Wednesday, scientists evaluated two nOPV2 candidates in parallel clinical trials in adults, toddlers, and infants in two different countries and compared them to approved SabinmOPV2 designed as an alternative. The safety and immunogenicity were evaluated.

Professor Pierre Van Damme of the University of Antwerp, Belgium, who is the lead author of this study on adults, said: Vaccines mutate, become infectious, cause illness, and regain their ability to spread to areas with low vaccination rates. The nOPV2 vaccine is at least as safe and effective as the Sabin vaccine, appears to be genetically more stable, and can be an important breakthrough into a polio-free world.

In India, the national vaccination authorities emphasized the need for constant vigilance. “We remain vigilant and need a tool like this new vaccine as a late polio strategy,” said the chief executive officer.

Increased outbreaks of circulating vaccine-derived poliovirus (cVDPV) have challenged eradication efforts, with more than 90% of cases caused by mutations in type 2 poliovirus strains. This risk led to the global withdrawal of the Type 2 component of the oral trivalent vaccine in May 2016. However, this effort failed to control all type 2 poliovirus infections, increasing the number of cases of type 2 cVDPV from 71 to 739 in 2018. Cases in 2020 (as of December 3, 2020). On October 22, 2020, WHO maintained the classification of Type 2 cVDPV as a public health emergency of international concern.

Polio is a highly infectious viral disease that affects children under the age of five and causes paralysis in every 200 infections. Of those who are paralyzed, 5-10% die when their respiratory muscles become immobile. There is no cure, but polio can be prevented by vaccination against three types of polio (trivalent vaccines 1, 2, and 3).

Vaccination campaigns have nearly eradicated wild poliovirus from around the world. It has decreased by more than 99% since 1988, and in 2018 it decreased from an estimated 350,000 cases to 33 cases. Wild-type 2 and 3 polioviruses have been declared eradicated by WHO. Wild type 1 survives only in parts of Afghanistan and Pakistan. Dr. Ricardo Luttiman, the lead author of a study of children and babies in the fight against infectious diseases in emerging markets, a non-profit organization in the United States, said: infant. “

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