Frequent exposure to suboptimal temperatures in vaccine cold-chain system in India: results of temperature monitoring in 10 states

OBJECTIVE: To estimate the proportion of

time the vaccines in the cold-chain system in India are exposed to

temperatures of < 0 or > 8 °C. METHODS: In each of 10 states,

the largest district and the one most distant from the state

capital were selected for study. Four boxes, each containing an

electronic temperature recorder and two vials of diphtheria,

pertussis and tetanus vaccine, were placed in the state or regional

vaccine store for each study state. Two of these boxes were then

shipped - one per facility - towards the two most peripheral health

facilities where vaccine was stored in each study district. The

boxes were shipped, handled and stored as if they were routine

vaccine supplies. FINDINGS: In state, regional and district vaccine

stores and peripheral health facilities, respectively, the

temperatures in the boxes exceeded 8 °C for 14.3%, 13.2%, 8.3% and

14.7% of their combined storage times and fell below 0 °C for 1.5%,

0.2%, 0.6% and 10.5% of these times. The boxes also spent about 18%

and 7% of their combined times in transit at < 0 and > 8 °C,

respectively. In shake tests conducted at the end of the study, two

thirds of the vaccine vials in the boxes showed evidence of

freezing. CONCLUSION: While exposure to temperatures above 8 °C

occurred at every level of vaccine storage, exposure to subzero

temperatures was only frequent during vaccine storage at peripheral

facilities and vaccine transportation. Systematic efforts are

needed to improve temperature monitoring in the cold-chain system

in India.