As polio vaccine supplies decrease, the WHO is encouraging countries administering the vaccine to give increasingly smaller doses to make their supplies last until more can be produced. The declining supplies are fueled in part by a WHO desired switch from a live vaccine to an inactivated one, which suppliers are struggling to get “enough raw material of the polio virus” for. By encouraging smaller doses, supplies will be able to last twice as long (Reuters). Though considered to be an emergency response to a shortage, this is not the first time that doses have been cut to deal with polio outbreaks. One such time was earlier this year in India where doses were cut into fifths and the response proved successful (Bahl et al.).
Poliovirus, a member of the Picornaviridae family, has been a target of a worldwide eradication program since the late 1980s. During this time, there has been a focus on transitioning from the use of the live oral polio vaccine to an inactivated polio vaccine. This is largely due in part to a desire to reduce the risk of vaccine-associated paralytic polio that could be associated with the oral vaccine as it is “shed in stool” for weeks after administered (Wallace and Alexander).
Wallace & Alexander (CDC) - http://www.cdc.gov/vaccines/pubs/pinkbook/polio.html
Bahl et al. (MMWR) - http://www.cdc.gov/mmwr/volumes/65/wr/mm6533a5.htm
Reuters (NY Times) - http://www.nytimes.com/reuters/2016/10/21/world/europe/21reuters-health-polio.html?mtrref=query.nytimes.com&gwh=39A7E0E20C7C130321635F27490137D3&gwt=pay&_r=0
- Devon Zander