Bivalent Oral Polio Vaccine Research Articles

Paralytic Poliomyelitis Associated With Sabin Monovalent and Bivalent Oral Polio Vaccines in Hungary

Historical records of patients with vaccine-associated paralytic poliomyelitis (VAPP) in Hungary during 1961-1981 were reviewed to assess the risk of VAPP after oral polio vaccine (OPV) administration. A confirmed VAPP case was defined as a diagnosis of paralytic poliomyelitis and residual paralysis at 60 days in a patient with an epidemiologic link to the vaccine. Archived poliovirus isolates were retested using polymerase chain reaction and sequencing of the viral protein 1 capsid region. This review confirmed 46 of 47 cases previously reported as VAPP. Three cases originally linked to monovalent OPV (mOPV) 3 and one case linked to mOPV1 presented after administration of bivalent OPV 1 + 3 (bOPV). The adjusted VAPP risk per million doses administered was 0.18 for mOPV1 (2 cases/11.13 million doses), 2.96 for mOPV3 (32 cases/10.81 million doses), and 12.82 for bOPV (5 cases/390,000 doses). Absence of protection from immunization with inactivated poliovirus vaccine or exposure to OPV virus from routine immunization and recent injections could explain the higher relative risk of VAPP in Hungarian children. In polio-endemic areas in which mOPV3 and bOPV are needed to achieve eradication, the higher risk of VAPP would be offset by the high risk of paralysis due to wild poliovirus and higher per-dose efficacy of mOPV3 and bOPV compared with trivalent OPV.

世界ポリオ根絶の失われた10年とポリオ根絶計画のこれから

The Global Polio Eradication Initiative was aimed to eradicate poliomyelitis by the year 2000, however, polio eradication is still not in sight even in 2010, over 10 years after the initial target date. In 2010, indigenous transmission of wild polioviruses has been interrupted throughout the world except four countries, Afghanistan, Pakistan, India, and Nigeria. Despite the intense use of monovalent oral polio vaccines, type 1 and type 3 wild polioviruses still circulate in the four remaining polio-endemic countries, and multiple importations of wild polioviruses have also occurred extensively from Nigeria and India to a number of previously polio-free countries in Africa, Asia, and Europe. Furthermore, the emergence of type 2 vaccine-derived polioviruses has raised concerns about low level of immunity against type 2 poliovirus in some polio-endemic areas like Nigeria and India. On the other hand, operational improvements in 2009 were reported in high-risk states in northern Nigeria and transmission of type 1 and type 3 polioviruses in Nigeria is markedly declining from 2009 to 2010. Moreover, bivalent oral polio vaccine containing Sabin 1 and Sabin 3 strains has been introduced in 2010 as a promising tool to improve and simplify the supplemental immunization activities in high-risk areas. Although there was no apparent decline in the annual number of polio cases in 2000-2009 globally, it would be critical to review our experience during "the lost decade of global polio eradication" to move forward into the final stage of global polio eradication.