Regulator nixes Indian Immunologicals plan for 6-in-1 vaccine over China polio strain

The Central Drugs Standard Control Organisation’s (CDSCO) decision, linked to the use of the China-sourced poliovirus antigens highlights how public-health security and biosafety considerations matter the most, even as vaccine makers push to introduce next-generation combination shots in a market immunizing tens of millions of children each year.

While the hexavalent vaccine is not used under the government’s universal immunization programme as of now, it is available in the private sector, wherein a parent can choose to pay for hexavalent vaccines.

A regulatory clearance for IIL and the following set of approvals would have paved the way for the vaccine’s commercial launch in India.

According to government documents, the primary cause for the rejection is the company's use of Chinese firm Sinovac's antigens that have never been used in any approved polio vaccines—oral or injectable—in India. While 10.01 million doses of this specific Sabin Inactivated Poliovirus Vaccine (sIPV) have been distributed globally; the usage has been restricted to China, Thailand and Pakistan.

The decision follows a high-level review by the subject expert committee (SEC) for vaccines, which raised an alarm over the safety and containment of the Chinese polio strain. The CDSCO reminded the firm that the South-East Asia Region, including India, has been certified polio-free since 2014.

Preventing reintroduction of the virus is a matter of national security, said health experts. While they are weakened, they can "revert" to more dangerous, virulent forms, leading to outbreaks of circulating vaccine-derived polioviruses (cVDPV). This risk is particularly acute because the Sabin strains used in such vaccines are inherently unstable.

Polio-free status

The World Health Organization (WHO) had declared India free of poliomyelitis in 2014, with the last recorded case of Wild Polio Virus (WPV) occurring in 2011. Around 167 million children are immunized during each National Immunization Day to mitigate the risk of virus importation and maintain population immunity.

The panel of experts convened a meeting on 22 December to advise the Drugs Controller General of India (DCGI), wherein it was highlighted that IIL had failed to submit ‘post marketing surveillance’ data, including real-world safety reports from those 10 million doses distributed in other countries.

It also said there was no study available for this specific hexavalent vaccine containing the Chinese-sourced antigens in any population to date. Moreover, the Chinese manufacturer of these antigens lacked approval under the WHO’ Poliovirus Containment Certification Scheme (CCS).

The committee concluded that a "considered decision cannot be taken at this stage" for the IIL trials to proceed.

Poliovirus containment certification, implemented in line with WHO’s global action plan (GAP-III), provides assurance through stringent biosafety, biosecurity and oversight mechanisms.

What hexavalent vaccines promise

The vaccine in question is a complex biological cocktail designed to protect infants against six major diseases in a single injection— diphtheria, tetanus, whole-cell pertussis (whooping cough), hepatitis B, haemophilus influenzae type-B (Hib), and polio.

By combining them, healthcare providers can reduce the number of needle pricks a child must endure, significantly easing the burden on parents, reducing programmatic costs, and improving overall vaccine coverage. Known as a ‘hexavalent’ vaccine, it is considered the future of pediatric immunization.

Currently, India’s universal immunization programme (UIP) is one of the largest public health initiatives in the world and does not use any ‘6-in-1’ shot nationally. While the hexavalent vaccine is available in the private sector; the government’ UIP relies on a combination of the ‘pentavalent’ vaccine (protecting against five diseases) and separate doses of both the oral polio vaccine (OPV) and the fractional inactivated polio vaccine (fIPV).

India provides immunization services to an estimated 25.7 million children and 29 million pregnant women every year.

What Indian Immunologicals says

Dr K. Anand Kumar, managing director of IIL, in a response to Mint’s queries over the phone said, “It is important to understand that Sinovac is not a new or 'foreign' entity to our market; they have been selling hepatitis-A vaccine bulk to one of the Indian companies for nearly seven years."

He said the company's tie-up for the Sabin inactivated polio vaccine (sIPV) bulk was based on “its superior safety profile".

"Unlike the Salk IPV, which is derived from a wild virus, the Sabin version uses an attenuated form of the virus that is then inactivated, making it much safer from a containment perspective. Furthermore, these are not 'Chinese strains' in a proprietary sense. These strains are distributed and routed through the WHO and the Netherlands Institute. In fact, the Sabin IPV manufactured by Sinovac is already a WHO pre-qualified vaccine," Dr Kumar added.

“Transition is a logical step for India’s public health. The new combination offers significant advantages for a nation with an annual birth cohort of 27 million by reducing the burden on parents and simplifying the massive logistics involved in vaccine procurement," he said.

The experts panel said the polio viruses stored for research and vaccine manufacturing must be safely contained in certified ‘polio-essential facilities’ (PEFs). The risk of a "facility-associated release"—a laboratory or factory leak—is a nightmare scenario for public health officials.

It warned that ingestion is the natural route of transmission, and even fully vaccinated factory workers could become infected and shed the live virus into the community through wastewater, contaminated skin, or air.

“We have already successfully completed all pre-clinical toxicology studies and have manufactured the initial batches. While the SEC has requested specific containment certificates from Sinovac, we have already communicated this to our partners to expedite the process. We will oblige and meet all requirements set forth by the SEC," Dr Kumar said.

Although post-market surveillance data is being sought, it must be noted that the Sabin IPV programme is relatively new globally, with licences currently in China and sales in markets like Pakistan and Bangladesh, he said.

"Ultimately, bringing more players into this space is essential for cost-competitiveness. Our programme is designed to support both the private market with single-dose vials and the government’s Universal Immunization Programme with multi-dose formats, should they choose to transition to hexavalent protocols," Kumar reasoned.

What other companies and experts say

Companies, including Serum Institute of India (SII), Panacea Biotec, GSK and Sanofi, already offer a hexavalent vaccine in India. Biological E is also trying to bring its hexavalent vaccine.

A spokesperson for Panacea Biotec, the creator of EasySix, world’s first fully liquid wP-based hexavalent vaccine, in an email response to a query said, “The SEC outcome signals India’s regulator is aligning with WHO’s Global Action Plan, making poliovirus facility certification non-negotiable. Manufacturers must demonstrate robust alignment with containment frameworks, proactively engage with National Authorities for Containment, and share broad international safety data to satisfy evolving global expectations on vaccine quality and biosafety."

"Poliovirus Containment Certification is a non-negotiable strategic biosecurity imperative. Safeguarding India’s hard-won polio-free status requires absolute assurance that no poliovirus can escape manufacturing facilities. This certification, per WHO’s GAP-III, provides that assurance through stringent oversight, reinforcing confidence in our vaccine ecosystem," Panacea Biotec said.

Queries emailed to the spokespersons of health and family welfare as well as external affairs ministries and the DCGI on 15 January, and the Chinese embassy in New Delhi and Sinovac on 16 January remained unanswered until press time. Queries emailed to Serum Institute, GSK and Sanofi on 15 January also weren't answered.

Experts say national security and safety are a concern while conducting such trials.

Dr Naveen Thacker, executive director of the International Paediatric Association (IPA), a non-governmental professional body representing over 1 million specialists globally, said, “The proposal to use the Sabin strain, the same strain used in the oral polio vaccine (OPV) presents a unique challenge. If there is an accidental leak from the lab during trials and it reverts back, then there will be issues in keeping polio-free status of India. Conducting such trials is simply not possible without robust, WHO-certified facilities to manage the storage and handling of the materials."

He said the missing post-marketing surveillance (PMS) data was a red flag. “What happened post-marketing? That data is only from Pakistan and China that is not enough; so we cannot risk that, said Dr Thacker." India is not currently facing a shortage that would justify taking such a risk. We have enough supply of the traditional IPV now. That was an issue a few years back, but now supply is not an issue."

Polio—a debilitating flaccid paralysis, destroys childhood and life—has varied strains and wild polio can still exist in some countries, said Dr Sanjeev Bagai, a senior consultant paediatrics, chairman of Nephron Clinics in New Delhi.

“Any additional strain of polio in the six-in-one vaccines must be compliant with all guidelines and regulations. The strain must have clinical real-world data validation of phased trials, which document the threshold of vaccine effectiveness. If the Chinese data is missing, then it’s best not to use that vaccine," he said adding that there was no need for compromise in India's infectious disease surveillance. “The worst thing is to bring in a neurotropic unverifiable strain on Indian shores."