You might not be aware of a massive bird flu epidemic ripping its way across the U.S.:

Iowa, where one in every five eggs consumed in the country is laid, has been the hardest hit: More than 40 percent of its egg-laying hens are dead or dying. Many are in this region, where barns house up to half a million birds in cages stacked to the rafters. The high density of these egg farms helps to explain why the flu, which can kill 90 percent or more of a flock within 48 hours, is decimating more birds in Iowa than in other states…

About 90 percent of the more than 25 million chickens that are being destroyed in Iowa produced liquid eggs, and already the wholesale price for those eggs nationwide has nearly doubled from late April. It hit $1.23 a dozen on Wednesday, up from 63 cents a dozen on April 22, according to Rick Brown, executive vice president and an egg specialist at Urner Barry, a market research publisher. The federal Department of Agriculture’s weekly report, however, was more cautious in its estimates of rising shell egg prices, but suggested that sharp increases for liquid eggs may be in the offing.

Major companies that use liquid eggs have started to warn that they may run short, which will impede sales and raise prices for products like cake mixes and ice cream. Nestlé, for instance, which makes Dreyer’s, Edy’s and Häagen-Dazs ice creams, as well as other products that incorporate eggs, said it had been discussing its options.

While the economic consequences are severe, there’s a public health issue as well. Both the MMR (measles-mumps-rubella) vaccines and the influenza vaccines are made with eggs (there are non-egg based versions of the flu vaccine, but the majority of the vaccine doses is derived from eggs). And not just any eggs can be used–there are regulations about potential exposure to pathogens*. You’re not getting the ‘vaccine eggs’ from the grocery store. We need about three eggs to make one dose of flu vaccine (I haven’t been able to find information about the MMR vaccine), but we’re looking at a total greater than a billion eggs per year (and remember, these eggs are special).

So does anyone know if our ‘vaccine egg’ supply is safe?

*The flocks are “specific-pathogen-free (SPF) closed flocks”, where “closed” means a genetically quantified (no new introduction of breeding stock) flock (pdf).