Inactivated polio vaccine (IPV)
IPV is produced from wild-type poliovirus strains of each serotype that have been inactivated (killed) with formalin. As an injectable vaccine, it can be administered alone or in combination with other vaccines (e.g., diphtheria, tetanus, pertussis, hepatitis B, and haemophilus influenza). Generally three spaced doses are administered to generate adequate levels of seroconversion, and most countries, a booster dose is added during late childhood. IPV has been used successfully in the polio eradication programs in a few countries, notably in Scandinavia and the Netherlands, but until recently most countries have used the oral polio vaccine. IPV provides serum immunity to all three types of poliovirus, resulting in protection against paralytic poliomyelitis. Most studies indicate that the degree of mucosal immunity in the intestine is significantly less than that provided by OPV, although this difference may be less pronounced in the pharyngeal mucosal lining. Adverse events following administration of IPV are very mild and transient. Due to the risks associated with the large quantities of poliovirus needed for IPV production, following the global cessation of poliovirus transmission high level (BSL-3/polio) containment of all manufacturing and quality control areas where live virus is handled must be implemented.