- A freeze watch indicator consists of asmall vial of red liquid attached to a white card and covered in plastic. The vial breaks if the temperature where the indicator is located drops below 0° C for more than one hour. These are very useful for cold sensitive vaccines like DTwP, DTaP, TT, DT, Td, TT,
hepatitis B
Dr. Jayaprakash
Superintendent, ICH.
Institute of Child Health.
Gov. Medical College Kottayam.
Kerala, India.