However, the phenomenon of original antigenic sin results in the competition between preexisting and newly developed immunity and thereby attenuates the immune responses to current viral infection, and consequently may blunt the protection from current influenza infection.
To verify that mice developed immunity to the CVB4 vector, serum samples, collected 7 days after the pre-immunization, were assayed for anti-CVB4 antibodies by ELISA.
By mutating and trading genes, bacteria have developed immunity to countless drugs.
As with the mice, the inoculated monkeys developed immunity: all three vaccines protected completely against infection.
Unfortunately for the pufferfish, its natural predators have developed immunity to the poison; humans on the other hand have not.
"When I saw the doctor he explained that because I'd missed the drugs I'd developed immunity.
Mr. Hicham explained that very few people wear protective gear, as many hunters have developed immunity and can withstand 20 or 30 stings while harvesting.
The physician Edward Jenner tested this connection by transferring fluid from a milkmaid's pustule to the skin of a young boy, who then developed immunity to smallpox.
However, there is very good evidence that people who were exposed during the first wave developed immunity — much as people get protection from a modern vaccine.
Experts said this might be because birds in Queens had developed immunity to the virus, and as the disease spread, Staten Island birds, which were barely exposed last year, might be especially vulnerable.
"Chickens are apparently more cosmopolitan," Dr. Crans said, "and from stock bred in other parts of the world have developed immunity; they show antibodies when bitten by infected mosquitoes but do not get sick".
