India’s national drug regulator has flagged a batch of the rabies vaccine Abhayrab as substandard and potentially spurious after it failed laboratory tests, even as the manufacturer maintains that the samples under scrutiny were not produced by it.In an August 27 letter to state drug regulators, Drugs Controller General of India (DCGI) Rajeev Singh Raghuvanshi directed officials to monitor the movement and distribution of Abhayrab batch KE25012 and take regulatory action wherever necessary.The move followed tests conducted by the Central Drugs Standard Control Organisation’s (CDSCO) laboratory in Kasauli, which found that a field sample of the vaccine failed to meet potency requirements. The sample was classified as “not of standard quality” and “misbranded”.The CDSCO also identified several discrepancies between the sampled product and a retained reference sample of the same batch previously submitted by Indian Immunologicals Limited (IIL) for regulatory testing. The differences included labelling, artwork, QR-code verification, cap colour, licence details and packaging text.Indian Immunologicals Limited, which manufactures Abhayrab through its Human Biologicals Institute division, said the samples from batch KE25012 had been collected from an unlicensed residential premises in Delhi’s Mukherjee Nagar.“The same laboratory report records 17 differences between the vial examined and the retention samples of the same batch held at the laboratory, which were submitted by us for batch release. On that basis, the vials examined are not products manufactured by the Human Biologicals Institute,” the company said.IIL said the genuine batch KE25012 had been independently tested and cleared by the Central Drugs Laboratory, which issued a batch-release certificate on November 7, 2025. The company said 83,370 vials from the batch were distributed only through authorised channels and that it had received no market complaints regarding the batch.According to IIL, every batch of Abhayrab is released for sale only after independent testing and certification by the Central Drugs Laboratory. “Vaccines administered through hospitals, clinics, government facilities and licensed pharmacies reach patients through an authorised supply chain and are not affected by this matter,” it said.The company added that it had submitted manufacturing, quality-control, reconciliation and distribution records to the CDSCO and had urged the DCGI to trace the source of the suspect vials and take action against those responsible. It said it was fully cooperating with the investigation.The vaccine had previously come under scrutiny in December 2025, when health authorities in the UK, the US and Australia warned travellers about counterfeit rabies vaccines reportedly circulating in India since late 2023.Abhayrab, India’s first Vero cell rabies vaccine, has been manufactured by the government-owned IIL since 2000 and accounts for an estimated 40 per cent of the domestic market.According to estimates published in 2024 by the Indian Council of Medical Research-National Institute of Epidemiology (ICMR-NIE), India records about 9.1 million animal bites annually, more than three-quarters of them caused by dogs. The study estimated that rabies causes 5,726 human deaths in the country every year.The CDSCO said in a statement that none of the affected batch had been exported to any other country. Four persons have been arrested by the Delhi Police in connection with the case. Further investigations and appropriate legal action are being carried out.