The Indian drug regulator has ordered a probe in response to traces of polio type 2 virus reportedly being found in several batches of an oral polio vaccine. The tainted vaccine has put the country's polio-free status at risk.
The Central Drugs Standard Control Organization (CDSCO) formed a three-member committee to find out how and why a Ghaziabad-based pharmaceutical company, Bio-Med Pvt Ltd, released three batches containing 150,000 vials of polio vaccines with traces of type 2 strain.
The Drugs Controller General of India has directed the company to stop the "manufacture, sale or distribution of the vaccine till further orders,” the Press Trust of India reported.
"The company has five directors. While the managing director has been arrested, we have asked the police to trace the rest directors as they also need to be questioned," a government official was quoted as saying in the report.
Why might polio type 2 in the vaccine cause up a polio infection
There are three serotypes of wild poliovirus: Type 1, type 2, and type 3. Earlier, a trivalent vaccine was administered to children to control all three virus types.
In September 2015, type 2 virus was eradicated from the world; the last virus was detected in India in 1999 and the type 3 poliovirus has not been detected anywhere in the world since 2012.
However, continued use of trivalent oral polio vaccine (OPV) has caused outbreaks of vaccine-derived polio virus (VDPV), as the type 2 virus mutated in the vials.
Medical fraternities and the World Health Organization (WHO), along with the Indian government, advocated for the removal of type 2 polio strains. They introduced a bivalent polio vaccine to eliminate the possibility of VDPV outbreaks. The switch from trivalent to bivalent polio vaccine was also made globally.
‘Low probability, high impact'
T. Jacob John, emeritus professor at the Christian Medical College of Vellore, who had been demanding the removal of trivalent OPV since the year 2004, told CGTN, “The presence of type 2 virus in the tainted vaccine makes babies born after April 2016 susceptible to polio.”
“It has led to a low probability, high impact situation for the spread of the polio virus in the country.” The tainted vaccine was distributed in large parts of Uttar Pradesh, Maharashtra, and Telangana. State governments and the WHO have increased surveillance in these areas.
Authorities fear a strain of type 2 OPV that contains weak but live polio viruses that are shed by vaccinated children in their stools might result in a flare-up of the disease.
Health workers are trying to trace children who were administered the tainted vaccine. India was declared polio-free in March 2014.
(Cover Image: An Indian health official administers oral polio vaccine drops to new born babies at a government hospital in Agartala on January 28, 2018. /VCG Photo)