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¦.
4 Some people should not get typhoid vaccine or should wait. Anyone who has had a severe reaction to a previous dose of this vaccine should not get another dose. Live Typhoid Vaccine (Oral). 1  Anyone who has had a severe reaction to a previous dose of this vaccine should not get another dose.yphoid vaccine can prevent typhoid. 2 Typhoid 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).