Reports from a surveillance mechanism of the Health and Family Welfare Department of the Government of India as well as World Health Organisation surveillance reports from Uttar Pradesh showed signs of the type-2 polio virus in stool samples of some children, following which the samples of Oral Polio Vaccines administered to children were sent for testing. This has set off a chain reaction of events, triggering a heated controversy in the realm of public health in India.

The test reports confirmed that some batches were contaminated with type 2 polio virus, the manufacturing, distribution and use of which was stopped after global eradication of the virus in 2016.

“In what can pose a serious threat to public health, some batches of oral polio vaccine manufactured by a Ghaziabad-based Biomed have been found to be contaminated with polio type 2 virus — a strain which has been eradicated worldwide, including in India,” reported The Times of India on September 30, 2018.

Three batches of polio vaccines containing 1.5 lakh vials were found contaminated with type 2 polio virus, which put India’s “polio free” status at huge risk, as children born after April 2016 — when the type 2 virus was withdrawn worldwide including in India — do not have immunity to this particular virus, while the virus was still alive in the system.

The Drugs Controller General of India (DCGI) filed an FIR against Biomed and the company’s managing director was arrested. The DCGI has asked the company to “stop manufacture, sale or distribution till further orders.” The government has ordered a probe to find out why the type 2 strain was retained by Biomed even after the central drug regulator had ordered all manufacturers in the country to take necessary measures for complete destruction of all traces of Polio Virus Type 2 by 25 April, 2016.

The contamination seems to have the potential to bring polio back to India. The health ministry and the Drug Controller General of India (DCGI) have initiated preventive measures to contain the impact. A senior official told The Times of India that they had alerted UP and Maharashtra where contaminated vaccines may have been used.

The spurious batch has been recalled from usage with immediate effect by the Uttar Pradesh government. The health ministry and the World Health Organisation (WHO) stepped up surveillance in Uttar Pradesh, Maharashtra and Telangana where the contaminated vaccines were administered to children.

The Central Drugs Standard Control Organization (CDSCO) constituted a three-member team to investigate the case. Not only this, the DCGI asked the Central Drug Laboratory (CDL) at Kasauli to check all batches of vaccines manufactured by all companies, for the type 2 virus strains.

The central health ministry assured that there was no need to panic and steps have been taken to deal with the aftermath of vaccine contamination. The ministry has asked states to step up efforts to increase the immunisation coverage in districts where contaminated vaccine has been used. The ministry also asked the states to administer injectable polio vaccine (IPV) to those children who have not received it yet, instead of Oral Polio Vaccines.

In India, the type 2 wild polio virus case was detected last in 1999, and type 1 polio in 2011. Type-2 component from polio vaccine was removed in order to minimise the risk of vaccine-derived poliovirus type-2, after the world was declared free from type-2 polio in 2014.

Do you need to worry if you’re a parent?

Meanwhile, a message went viral on WhatsApp and other social media, leading a lot of parents to worry about the Oral Polio Vaccine they administered to their children. Fact checks on the message were also circulated, quoting Dr Jyoti Joshi from the Center of Disease Dynamics, Economics and Policy (CDEP) who said that the OPV would continue to remain safe for administration. There are other manufacturers who didn’t have contaminated samples, and contaminated samples have been withdrawn, therefore children can be safely vaccinated with Oral Polio Drops, she said.

Another fact check article by The Better India advised people against vaccinating children when they suffer from fever cold or other health issues.

The Ministry of Health and Family Welfare, through Press Information Bureau, Government of India, issued a detailed clarification. “India was certified polio-free in March 2014 and continues to be so. India continues to  remain vigilant against all three types of polioviruses. The last polio case due to wild poliovirus in the country was detected on 13 January 2011,” clarifies the notification.

“The decision to switch to inactivated poliovirus vaccine (IPV) and bivalent Oral Polio Vaccine (bOPV) from trivalent Oral Polio Vaccine (tOPV) in all polio campaigns and routine immunization in India and elsewhere from April 2016 was taken  following certification of global eradication of type 2 wild poliovirus. In India, the last Type 2 wild polio virus case was detected in the year 1999. The tOPV that was used till April 2016  contained three types of poliovirus vaccines (P1, P2 and P3) and protected against all three types of wild polioviruses – type 1, type 2 and type 3, while bOPV contains two types of poliovirus vaccines (P1  and P3) and protects against type 1 and type 3 wild polioviruses. Type 2 component from oral polio vaccine was removed as a part of global polio endgame strategy.

As a part of efforts to maintain high immunity against all polioviruses, India provides inactivated poliovirus vaccine (IPV) and bOPV to all infants across the country under routine immunization… Recently, type 2 polio vaccine virus was found in some sewage and stool samples. The detection of type 2 vaccine virus indicates that a very robust polio surveillance jointly managed by MoHFW and WHO is still maintained even after 7 years have elapsed since last wild poliovirus case in the country was reported. This detection indicated the use of a type 2 poliovirus containing vaccine, despite the fact that tOPV that contained type 2 poliovirus vaccine had been phased out globally, and in India, in April 2016, as a part of the Polio Endgame strategy.

“On investigation, it was found that in a few vials of bOPV supplied by one manufacturer, there were traces of P2 vaccine. The Ministry of Health and Family Welfare taking WHO on board took immediate and comprehensive action,” says the clarification, explaining all the steps taken to recall the vaccine and take corrective actions.

“Type 2 polio vaccine virus traces which have been found in bOPV vials is the attenuated (weakened) poliovirus and does not cause paralysis and was also earlier used in tOPV till  April 2016. The recipients of such vaccine will usually shed the vaccine virus through fecal route for about 4-6 weeks after which it will die down,” assures the clarification.

“In light of all the above facts and measures taken, the risk of any child getting vaccine derived polio disease is practically nil. Sufficient polio vaccine from alternate sources is available in the programme to  implement Routine Immunization (RI) and Pulse Polio Immunization (PPI) and maintain the immunity against polio-viruses,” assures the note.

Implications

Why is there so much importance given to this event? Is there a cause for concern?

This article by Bengaluru-based doctor-activist Dr Sylvia Karpagam on The NewsMinute explains why India needs to worry about the event. ‘Firstly, the vaccine virus could mutate into a form that we are not prepared for and this could either be mild or fatal. Secondly, the vaccine virus could spread and cause a vaccine-related poliomyelitis outbreak or epidemic, depending on the vulnerability of the exposed population,’ she writes.

The whole incident brings to light the need to have better control over vaccine manufacturing, as there have been vaccine-derived polio incidents reported in the past. The concerns over vaccine-associated paralytic polio and non-polio acute flaccid paralysis make it all the more important to take steps to rule out any public health emergency.