OPV vs IPV

Comparative Profile

Feature	Oral Poliovirus Vaccine	Inactivated Poliovirus Vaccine
Preparation	Live-attenuated Sabin strains grown in monkey kidney or Vero cell cultures.	Formaldehyde-killed Salk strains grown in Vero cells, monkey kidney, or human diploid cells.
Administration Route	Oral administration consisting of two drops.	Intramuscular injection or intradermal fractional dose.
Immune Response	Induces both systemic and excellent intestinal mucosal immunity via secretory immunoglobulin A.	Induces strong systemic humoral immunity via immunoglobulin G. Weak induction of intestinal mucosal immunity.
Herd Effect	Confers contact immunity due to fecal shedding of vaccine virus, protecting unimmunized contacts.	Lacks contact immunity transmission. Does not significantly reduce wild virus circulation in poor sanitation settings.
Safety Profile	Risk of vaccine-associated paralytic poliomyelitis and circulating vaccine-derived polioviruses.	Extremely safe. Zero risk of vaccine-associated paralytic poliomyelitis or vaccine-derived polioviruses.
Contraindications	Contraindicated in immunodeficiency and household contacts of immunocompromised individuals.	Safe for administration in immunocompromised patients.
Temperature Sensitivity	Highly heat-sensitive. Potency monitored via vaccine vial monitor.	Relatively heat-stable but damaged by freezing.

Wild poliovirus type 2 eradicated globally in 1999.
Continued emergence of circulating vaccine-derived poliovirus outbreaks noted primarily in high-risk areas.
Approximately 90 percent of all vaccine-derived poliovirus outbreaks attributed to Sabin type 2 strain.
Vaccine-associated paralytic poliomyelitis burden necessitated shifting toward safer inactivated alternatives.

Global coordinated withdrawal of trivalent oral poliovirus vaccine executed in April 2016.
Trivalent formulation replaced with bivalent oral poliovirus vaccine containing exclusively serotypes 1 and 3.
Discontinuation of type 2 oral vaccine aimed at halting emergence of type 2 vaccine-derived polioviruses.

World Health Organization mandated inclusion of at least one inactivated poliovirus vaccine dose in routine schedules globally.
Primary objective entails inducing baseline immunity against type 2 poliovirus following bivalent vaccine transition.
Sequential schedules utilizing inactivated vaccine prior to oral vaccine minimize vaccine-associated paralytic poliomyelitis risk while maintaining essential mucosal immunity.
Indian national schedule incorporates fractional intradermal inactivated doses at 6 weeks, 14 weeks, and 9 to 12 months alongside oral vaccine doses.
Ultimate endgame strategy involves complete withdrawal of all oral poliovirus vaccines and exclusive utilization of inactivated vaccines post-eradication.

Novel oral poliomyelitis vaccine type 2 developed through genetic stabilization of monovalent type 2 vaccine.
Significantly reduced genetic reversion to neurovirulent forms compared to conventional Sabin strains.
Deployed exclusively for targeted outbreak responses in regions experiencing circulating vaccine-derived poliovirus type 2 transmission.