Almost 50% of the US's egg-laying hens have not been given vaccines that could have prevented the recent recall of more than half-billion eggs due to salmonella, it was reported on CNBC.
The news channel reported that Gary Baxter, spokesman French pharmaceutical company CEVA, said that about 125 million of the 218 million egg-laying hens in the US have been vaccinated.
British farmers use a vaccine that goes into the hens’ drinking water. The British government began encouraging, but not requiring, vaccination after a salmonella scare in the late 1980s. According to Amanda Cryer, spokeswoman for the British Egg Information Service, egg sales dropped by 60% overnight.
Currently, about 90% of eggs in the Britain come from vaccinated hens. The remaining 10% come from very small farmers who may have vaccinated chickens but don't sell to major retailers.
Since Britain's vaccinations began, the only salmonella outbreaks in eggs have been linked to those imported from elsewhere in the European Union, Cryer said. Overall salmonella cases in the country dropped by half within three years.
Both of the farms involved in the recent recall vaccinated some of their chickens:
Julie DeYoung, a spokeswoman for Hillandale Farms, said the company began purchasing vaccinated laying hens in September 2009. The company didn't vaccinate older hens but replaced them with vaccinated ones as they went out of production, she said.
"So about 80% of the hens have been vaccinated," DeYoung said.
Wright County Egg has vaccinated some hens since 2009, investing more than $570,000 in the effort, spokeswoman Hinda Mitchell said. She declined to offer details due to an FDA investigation but said young hens were vaccinated "when they are in our care."
Dr. George Boggan, a veterinarian with CEVA, said they aren't always effective. If egg farms are dirty, and there's a lot of contamination, the bacteria can "overwhelm" the protection from the vaccine.
The FDA (US Food & Drug Administration) said last month it doesn't believe mandatory vaccination is necessary, but it supports farmers doing it voluntarily.
Data on the vaccine's effectiveness in field trials conducted in real world conditions "was insufficient to support a mandatory vaccination requirement," the agency said in the text of new rules requiring increased inspections and testing of eggs.