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¦.
The last dose should be given at least. 1 week before travel to allow the vaccine time to. work. â¢A booster dose is needed every 5 years for people. who remain at risk. Either vaccine may be given at the same time as. other vaccines. There are two vaccines to prevent typhoid. One is. an inactivated (killed) vaccine gotten as a shot, and. the other is live, attenuated (weakened) vaccine. which is taken orally (by mouth). 2 Typhoid vaccines. 4 Some people should not get. typhoid vaccine or should wait.