THERMOSTABILITY OF RINDERPEST VACCINE VIRUS AFTER ADAPTATION TO VERO CELLS

Stability of Vero-cell-adapted rinderpest vaccine virus with 2 differe nt stabilizers, viz. 5% lactalbumin hydrolysate (LAH) plus 10% sucrose (LS stabilizer) and 5% LAH plus 10% lactose (LL stabilizer), was test ed at various temperatures. At 4 degrees C, no loss in infective titre s was found after 3 months of storage. At 25 degrees C on storage for 29 days, loss of infectivity was nonsignificant. A significant (P < 0. 05) linear decline in the titres was observed when stored at 37 degree s C for 21 days as well as at 45 degrees C for 8 days. Based on declin ing degradation curves observed at different temperatures, the vaccine is expected to reach the minimum W.H.O. requirement of 2.5 log(10) TC ID50 after storage for approximately 305 days (LS) and 123 days (LL) a t 25 degrees C; 28 days (LS) and 48 days (LL) at 37 degrees C; and 3 d ays (LS) and 7 days (LL) at 45 degrees C. Stabilizer LL was-found to b e marginally superior to LS at 37 degrees and 45 degrees C.