WHO prequalifies additional nOPV2 vaccine, strengthening global fight against polio

Prequalification confirms that the vaccine meets stringent global standards for safety, quality, and effectiveness, allowing UN procurement agencies, including UNICEF, to purchase and distribute it worldwide.

Polio, which once paralyzed hundreds of thousands of children annually, is now close to eradication thanks to sustained vaccination campaigns.

However, outbreaks caused by circulating vaccine-derived poliovirus type 2 (cVDPV2) can occur in under-immunised communities.

The newly prequalified nOPV2 is engineered to be genetically more stable than earlier vaccines, reducing the risk of seeding new outbreaks while still rapidly halting virus transmission.

What is nOPV2 and why does it matter?

The novel oral polio vaccine type 2 was specifically developed to combat outbreaks caused by vaccine-derived polioviruses.

In areas with low immunisation coverage, weakened viruses in older vaccines can mutate and regain virulence, leading to cVDPV2 outbreaks. nOPV2 addresses this by being genetically more stable, lowering the likelihood of reversion to a pathogenic form.

The newly prequalified vaccine is produced by Biological E. Limited, expanding global supply capacity beyond the original manufacturer in Indonesia.

Diversifying production ensures countries can respond more reliably and rapidly to emerging outbreaks.

Global wild poliovirus cases have declined by more than 99% since the 1980s, but gaps in immunisation still allow cVDPV2 outbreaks. nOPV2’s stability helps reduce this risk.

Implications for India

India, which achieved polio-free certification in 2014, runs one of the world’s largest childhood immunisation programmes.

Oral polio vaccine (OPV) remains central to both routine schedules and mass campaigns.

While the risk of importations or vaccine-derived outbreaks persists if coverage drops, the prequalification of nOPV2 ensures access to the latest, high-quality vaccine, reinforcing India’s hard-won polio-free status.

India is also a global vaccine manufacturing hub. With companies like Biological E now contributing significantly to nOPV2 production, the country plays a critical role in supplying quality-assured vaccines to low- and middle-income countries.