The only problem with such a time period -- proposed by the Centers for Disease Control -- is that the six major interruptions, involving six of eight recommended childhood vaccines, between November 2000 and February 2004 ranged in duration from seven months to 20 months, the scientists report in the April 24 issue of the journal Vaccine.
Spending another $500 million up front would ensure sufficient quantities for a 12-month interruption, said operations researcher Sheldon H. Jacobson, professor of mechanical and industrial engineering at the University of Illinois at Urbana-Champaign.
The CDC's "choice of six months is unclear," given the actual timelines of recent production interruptions, Jacobson said.
"It appears that we are being overly concerned in the short-term over a few hundred million dollars, whereby the potential risk to the 4 million children born every year is so great," Jacobson said. "When you consider how strained the nation's health-care system is right now, a one-time expenditure of a few hundred million dollars of stockpiled vaccines goes such a long way to protecting the approximately 11,000 children born every day in the United States. This is something we can control. It is not clear why it is not being done."
The researchers used a stochastic inventory model in which they considered multiple variables, including differing vaccination coverage rates, getting vaccines on time, production downtime, the ramp-up process to replenish supplies and the number of children born each day. While described briefly in the Vaccine paper, the full technical description of data and the analyses will be published in a separate journal.