Monday, 22 February 2016

Understanding roadblocks to delivering heat stable vaccines in developing nations

The vaccination industry in developing countries is challenged by a plenty of roadblocks and the one major factor that contributes to all the others is ‘vaccine delivery’. These nations are faced with a daunting question of how to ensure receiving and transferring vaccines to the country’s population in order to protect the human lives and thus reduce mortality rate.

Maximum number of vaccines that are supplied to developing nations are done by multi-national level players and therefore are not commissioned according to the ecological and geographical needs of the developing world population. In addition, the challenge of transporting and storing vaccines at refrigerated temperatures needs to be addressed on many fronts since more and more new and expensive vaccines are introduced and are at a risk of damage from heat and/or freeze exposure in these countries.

In 2012, World Health Organization (WHO) proposed new programmatic suitability requirements for vaccines purchased by United Nations agencies that set mandatory minimum stability standards and signalled a preference for vaccines that are temperature stable and can be stored for extended periods of time above 8˚C.[1] It also resulted in successful development of MenAfriVac® which was labelled for controlled-temperature chain (CTC) use, however, there is still a gaping need for vaccines with improved stability and mitigation of supply chain challenges.

A recent review of published cold chain studies in developing nations found that freezing temperatures were encountered during transport (35.3%) or storage (21.9%) of all vaccine shipments monitored in these countries.[1]

According to another study conducted on select developing countries, 46% of all participants from these nations believed that exposure to heat was a greater concern, 32% believed that heat and freezing were equal concerns. On the other hand, only 35% of participants agreed to freezing temperatures being a problem in their respective country’s immunization program. In case of India, 71% participants agreed to the same.[1] Further, poor refrigerator performance and improper icepack conditioning was reported by 53% and 28% of these participants, respectively. In terms of solutions, 59% of respondents were willing to pay extra for liquid rotavirus vaccine, however, 59% were unwilling to switch to lyophilized vaccines (for hepatitis B vaccine).

Although vaccines are recognised as a cost-effective method of prevention in most countries and an only chance at survival, the benefits of immunization are not far-reaching and it has a less-than-optimal vaccine delivery system.

The cold chain has been a critical component in successful delivery of vaccines worldwide, but it is still a vulnerable part of the overall immunization programmes in developing nations. Better transportation, equipment can address the problem of unplanned vaccine freeze exposure and maintaining optimal quality at the time of delivery. In addition, creation of thermostable vaccine or the next generation vaccines, can also provide answers to the complexity of having different rules for different vaccines and the accompanying need for additional training and tools (label modifications, better instructions etc.) to appropriately implement vaccine use. It will significantly contribute to reduction of vaccine wastage and ensure less dependence on CTC, facilitating wider outreach and thus, improving immunization.

[2] Matthias DM, Robertson J, Garrison MM, Newland S, Nelson C. Vaccine 25(20), 3980-3986 (2007)
[3] By Debra D. Kristensen, Tina Lorenson1, Kate Bartholomew, Shirley Villadiego
   Can thermostable vaccines help address cold-chain challenges? Results from stakeholder interviews in six low- and middle-income countries| PATH| Volume 34, Issue 7, 10 February 2016, Pages 899–904

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