Freezing temperatures in the vaccine cold chain: A systematic literature review

Abstract

The dangers of accidental freezing of vaccines in the cold chain have prompted studies throughout the globe to better characterize the risk. To date, there has been no systematic review of these studies. This analysis highlights that accidental freezing is pervasive and occurs across all segments of the cold chain. Between 14% and 35% of refrigerators or transport shipments were found to have exposed vaccine to freezing temperatures, while in studies that examined all segments of distribution, between 75% and 100% of the vaccine shipments were exposed. More rigorous study designs were associated with higher levels of freeze exposure. As more expensive, freeze-sensitive vaccines are introduced into immunization schedules, freeze prevention will become increasingly critical for ensuring that the world's children are receiving fully potent vaccine.

Descripción del transporte y conservación de las vacunas de adquisición particular

“…Además, gran parte de las vacunas, cuya información procedía de la farmacia, se conservaron en la puerta de la nevera, lugar más termolábil 1 . Ninguna de las dosis fue conservada en el congelador, pero no sabemos si las vacunas se congelaron, tal y como sucede en algunos países industrializados 15 , lo que podría haber afectado a la capacidad inmunizadora de la vacuna 14 .…”

Evaluation of an outside-the-Cold-Chain Vaccine Delivery Strategy in Remote Regions of Western China

“…The data shown are those inside-the-cold-chain and outside-the-cold-chain vaccines that were exposed below 0ºC and above 8ºC. 21 The routine use of Freeze Watch monitors is helpful for preventing vaccines from freezing in the cold chain. In this study, time/ temperature indicators were used to monitor vaccine exposure to heat, which is useful, but the range of time and temperature indicated is too narrow to monitor the cold chain successfully.…”

Vaccine Presentation and Packaging Advisory Group: a forum for reaching consensus on vaccine product attributes

“…Exposure of vaccines to excessive heat or freezing temperatures, which often occurs in such settings, can compromise their potency. [1][2][3][4] Although developing countries have maintained cold chain infrastructure since the 1980s, they often find it difficult to power, repair and replace equipment and to transport and store vaccines at the appropriate temperature. 5 Suboptimal vaccine management practices lead to frequent stockouts of critical vaccines and supplies.…”