The percentage of Oregon children who received fewer than two vaccines between birth and 9 months increased threefold from 2007 to 2009, suggesting the media attention given to “alternative” immunization schedules may be having an effect, according to study findings published online.
Steve G. Robison, BS, and colleagues from the Oregon Health Authority conducted a retrospective analysis of children in their system born in the Portland area between 2003 and 2009. The researchers said about 5% of children in the cohort of 97,711 children met their definition of “short-limiters,” or children who had been on alternative vaccination schedules, and the rate of children meeting this definition tripled from 2006 to 2009.
Robison and colleagues noted increased media coverage of “shot-limiting” in 2007, which may have contributed to the rise in alternative immunization schedule adopters.
“Although the identified pool of consistent shot-limiters is small, this group has translated their worries about vaccines into action and may represent the concerns of a larger proportion that may only episodically limit or delay, and who may have trouble finding accommodating providers,” the researchers wrote.
The researchers said their findings indicate a need for further data on the effect of delaying vaccine on individual disease incidence, as well as the population as a whole.
Disclosure: Mr. Robison reports no relevant financial disclosures.