AHMEDABAD: The city is among the two places in the country which had triggered a World Health Organization (WHO) alert about the return of the Vaccine-Derived Type 2 Polio Virus (VDPV2). The WHO had warned the Gujarat government a few months back about the virus. But on January 7, three days ahead of the Vibrant Summit, the Centres for Disease Control (CDC) of the US put out a worldwide alert in the public interest. Hyderabad in Telangana was the other Indian city where the virus was said to be making a comeback.Gujarat has been silent and unmoved, but the Telangana government had declared a “global emergency” back in June after detecting the wild type 2 polio virus. Telangana also had 2 lakh vaccines flown in from Geneva to inoculate more than 3 lakh children in Hyderabad and Ranga Reddy districts as a preventive measure. According to Gujarat health commissioner J P Gupta, more than 500 samples were taken from sewerage lines in Ahmedabad and a few samples had tested positive for the virus.Some of the samples collected on August 30 in Ahmedabad city tested positive for Sabin-like type 2 polio virus. The virus was detected approximately four months after the state health department was told to ensure a switch from the Trivalent Oral Polio Virus Vaccine (tOPV — consisting of types 1, 2, 3 polio viruses) to the Bivalent Oral Polio Virus Vaccine (bOPV — consisting of type 1 and 3 viruses). But despite the instruction, the detection of the vaccine-derived type 2 virus in sewerage clearly indicates that tOPV was still being used by medical practitioners and hospitals. In a test search in Ahmedabad, two tOPV vials were found at a private vaccine retailer and another 11 tOPV vials were found at eight private clinics. All tOPV vials had expiry dates ranging from December 2016 to November 2017.“There may have been some old stock of tOPV. The government, for its part, had destroyed all of those vaccines,” said Gupta. The samples were tested by a dedicated WHO team, including Dr Disha Patel of BJ Medical College. N P Jani from the Gujarat government had been coordinating the vaccine withdrawal.