TABLE 2.
Stability studies of lipid- and non-lipid-formulated Mycobacterium bovis BCG under laboratory and field conditions at different temperatures
| Condition | Temperature (°C) | Formulation | Vaccine | Length of stability | Viability/potency | Reference no. |
|---|---|---|---|---|---|---|
| Ambient room temperature | 18–24 | Lipid | BCG Danish | 7 wk | 50 | |
| 10–25 | Lipid | BCG Pasteur | 8 wk | Few viable M. bovis BCG isolates detected | 51 | |
| Refrigerated | 5 | Nonlipid | 8 wk | Fell to level of 10–20% | 27 | |
| 4 | Lipid | BCG Pasteur | 8 wk | Minimal loss of viability | 51 | |
| Frozen | −20 | Lipid | BCG Danish | 8 mo | Predicted time to 1-log10 decline in bacterial viability of 17.3 mo | 50 |
| −20 | Nonlipid | 8 wk | Fell to level of 10–20%a | 27 | ||
| Field studies | Variable | Lipid | BCG Danish | 3–5 wk in forest/pasture margin habitat | 50 |
a
A higher potency of BCG vaccine is maintained at lower temperatures.