However, enforcing a more focused vaccination strategy can be extremely difficult if interventions are needed immediately and under extreme public pressure and fear.
"I believe it's going to be extremely difficult, if not impossible".
Consequently it may be extremely difficult if not impossible to model, analyze and predict the failure behavior of system.
Authority officials have made clear that issuing more debt, paid for by riders, would be extremely difficult, if not impossible.
Such genetic manipulation would be extremely difficult, if not virtually impossible, to detect using current methods, scientists said.
However, cutting welfare state provisions in Europe to fund defense expenditures is going to be extremely difficult, if not counterproductive.
"It's going to be extremely difficult, if not impossible, to achieve the goals without increasing money spent on health," Chopra said.
What is clear, he said, is that it will be extremely difficult, if not impossible, to remove the snakes from southern Florida.
Maintaining that route would be extremely difficult if the city were significantly infiltrated by the very militants who want to defeat the NATO war effort across the border.
Environmentalists and several experts have warned that any oil spill would be extremely difficult, if not impossible, to clean up due to the fragile yet inhospitable Arctic environment.
He said it would be "extremely difficult, if not impossible" for Scotland to secure the agreement of the 28 other countries to join the EU.
