The other type is virulent (produces disease), is the cause of FIP, and is called feline infectious peritonitis virus (FIPV). It is believed that FIP occurs when FECV mutates to FIPV in the cat and starts to replicate in the cat's cells. What causes this mutation is unknown.he other type is virulent (produces disease), is the cause of FIP, and is called feline infectious peritonitis virus (FIPV). It is believed that FIP occurs when FECV mutates to FIPV in the cat and starts to replicate in the cat's cells. What causes this mutation is unknown.
How long does a typhoid shot last?   According to the CDC website, a booster dose is needed every 2 years for people who remain at risk.. The oral (live) vaccine lasts 5 years before another dose is neededâ¦.
1 According to a U.S. Centers for Disease Control and Prevention fact sheet, the oral vaccine provides immunity for five years, and the shot for two years. 2  Neither type of typhoid vaccine is 100 percent effective; both protect 50 to 80 percent of recipients. Side effects of the typhoid vaccine shot can include fever, headache or redness or swelling at the injection site; side effects of the oral vaccine can include fever, headache, abdominal discomfort, nausea, vomiting or, in rare cases, a rash.