Why the controversy?
Some newspapers carried news items regarding the contamination of oral polio vaccine which is being administered to babies. These reports raised queries that this can result in polio infection in the community.
What is the status of polio vaccine that is currently used in India?
India has been declared free from polio by the World Health Organization WHO, the apex global body, on March 27, 2014.Since the last 4 ½ years, this polio free status has been maintained by India.
The oral polio vaccine had contained three strains of the polio virus, Type 1, 2 and 3 . These are present in the attenuated form in the vaccine, meaning that they are capable of providing protection in the body, but do NOT cause disease. This Oral polio vaccine OPV was used to protect the infants against the infection caused by the Wild Polio Virus (WPV), that resulted in paralytic poliomyelitis.
Once the country was found to be polio free, the Type 2 strain was declared as eradicated, as there had not been any case detected since 1999.In order to ensure that there was no future likelihood of the vaccine strain of the virus causing any infection in the future, it was decided to move it out of the OPV drops. Hence the OPV which earlier contained 3 strains of the virus( Trivalent OPV/ t OPV)was subsequently converted to a bivalent OPV(b OPV). This is the OPV that is currently administered to all infants.
What about the Injectible Polio Vaccine (IPV)?
After the country was declared polio free, it was decided that a further thrust was needed to ensure a robust protection against polio infection. It was thus decided that every infant gets 3 doses of IPV along with 2 doses of OPV at various times during the course of the infnat’s immunization schedule. This vaccine contains all three strains of the virus and offers immunity against all the 3types of virus.
Currently, there is shortage in the availability of the IPV vaccine due to the demand -supply mismatch. Hence the IPV is administered in the government hospitals as 2 doses at 6 weeks and 14 weeks. For the private sector practitioners, IPV is available in the combination of vaccines with DTP, HiB and HBV. Three doses are administered along with one booster at 18 months.
Is there for parents need to worry regarding this controversy?
Any child who has received 2 doses of IPV or at least one dose of IPV ( either as part of the combination vaccine or singly)will have immunity to all the three strains of the Polio virus. The virus that has been recently isolated is of the vaccine type only .
All those infants who have not received IPV must be given at least one dose of IPV from the nearest government facility.
There is no need to panic. Please continue all the remaining vaccines as per the schedule, including the pulse polio immunization programs. These are essential to maintain the zero Polio status of our country.