Shot to protect against polio and five other diseases has been approved by Gavi

Why it matters: Combining vaccines can provide longevity.

Oral polio vaccines, administered in drop form, have reduced polio cases by more than 99 percent in recent decades. But because the drops contain live viruses — detectable in the feces of children receiving the vaccine — the virus can spread and cause new infections in countries with poor sanitation. The new vaccine will not have this problem.

“Today, by 2023, more children will be paralyzed by circulating vaccine-derived polio than by wild polio,” said Dr James Campbella pediatric infectious disease expert at the University of Maryland School of Medicine who studies vaccine development.

He called Gavi’s approval an “important step” in suppressing the virus globally, as it will give children in low- and middle-income countries access to a product that pediatricians in the United States and Europe have long been offering.

The injection is also expected to help prevent infections due to its logistical convenience. Since the polio vaccine will be packaged in a combination product that is already being distributed to children, scientists say countries using it are less likely to see a resurgence of polio once oral vaccines are scaled back.

Background: Polio has remaining strongholds in Afghanistan and Pakistan.

Polio, officially known as poliomyelitis, is a highly contagious viral disease that is mainly transmitted through fecal matter in places with poor sanitation. The virus multiplies in the gut and invades the nervous system, causing paralysis. Even a single existing case is problematic, experts say, because it could lead to a global resurgence.

The United States has long used an inactivated polio vaccine, or IPV, instead of oral drops, and Gavi has spent the last 10 years helping lower-income countries buy it. But the new six-in-one vaccine, called a hexavalent, will also protect children against hepatitis B, Haemophilus influenzae, tetanus, diphtheria and whooping cough.

Adding polio protection to the existing five-component vaccine will increase costs, but public health officials say the move is still economically beneficial. Generally less vaccine doses will help reduce small expenses that add up, including syringes, serum refrigerators, and appointments with healthcare professionals.

What’s next: A global rollout is on the horizon.

Countries that Gavi serves can now apply for funding for the vaccine, which could be available as early as 2024. It is given in three doses in the first months of life — plus a subsequent booster shot before age 2 — and UNICEF has estimated that the global market for the new vaccine could reach 100 million annual doses by 2030.