The World Health Organization has warned that the Zika virus is “spreading explosively” in the Americas and that as many as four million people could be infected by the end of the year. Even if the world’s largest drugmakers were to mobilize as fast as they could, and even if the science were straightforward, it’s unlikely a Zika vaccine could be developed quickly enough to address the expanding outbreak of the mosquito-borne virus.
U.S. and international governments are pushing forward with programs for Zika vaccines, and at least five pharmaceutical companies are either considering or actively pursuing programs, including: GlaxoSmithKline, Sanofi, Inovio Phamaceuticals, Bharat Biotech, and Takeda Pharmaceutical.
But while companies are actively working towards developing a vaccine, which could be years away, the likelihood of individuals receiving effective, non-compromised vaccines is alarmingly low. The WHO estimates that 50% of those living in affected areas will not actually receive the benefit of the vaccine because of cold chain management issues, including maintaining a consistent and safe temperature range from lab to patient. While there is still time, why not build out a stronger, more reliable delivery method to ensure the success of each vaccination once a Zika vaccine is available?
Some of the most important vaccines in the world are heat-sensitive, thus requiring custom transportation and storage to ensure their integrity and effectiveness. The process involving the transportation and storage of heat-sensitive products has been defined as the cold chain management. Cold chain management requires reliable refrigeration technologies to successfully move the vaccines from their manufacturers to the patient. Maintaining cold chain operations becomes a challenging quest for countries without reliable or limited access to electrical power.
The following infographic from msfaccess.org illustrates how the country of Chad struggles to keep vaccines at cold temperature since electricity available for refrigeration is limited:
Logistics are vital in determining the success of all cold chain management, which also relys heavily on successful transportation of temperature sensitive products through thermal and refrigerated packaging methods. These important and detailed coordination of operations from point of origin to point of consumption are vital to ensure the success of all vaccine storage and use.
Cold chain management aims to protect the integrity of products from the moment they leave the manufacturers until they reach the end users. The two major sectors concerned with cold chain logistics are the food & beverages and the bio-pharmaceutical industries. Several means of transportation are used in different stages of the cold chain, such as refrigerated trucks, refrigerated cargo ships, and air cargo. The following graphic illustrates some of the main components that are usually involved in any given cold chain:
For vaccines, the dynamic of the cold chain involves more links (different steps of transporting or storing that vaccines go through). Most heat-sensitive vaccines must be kept between a range of 2 to 8 degrees Celcius at any and every given point throughout the links of the cold chain. The following graphic outlines the steps involved in a typical cold chain for vaccines:
Source: World Health Organization. Vaccines, Immunization and Biologicals: The Cold Chain. November 26, 2002.
The preservation of an intact cold chain is imperative for the handling and transportation of temperature-sensitive drugs and vaccines, since temperature fluctuations are very likely to alter the effectiveness and outcomes of these drugs. One of the biggest challenges consists in preventing them from freezing, since freezing affects the quality of vaccines. The World Health Organization (WHO, 2006) reported that the impact on the potency of vaccines each time they’re exposed to ambient temperatures is cumulative; which highlights the importance of a successful cold chain from beginning to end.
The global expenditures on the cold chain market from the bio-pharmaceutical industry rose from $5.1 billion in 2010 to $6.6 billion in 2011. The market will continue to grow as many more of the top global pharmaceutical products and vaccines require cold-chain handling, such as influenza vaccines, Hepatitis A & B, and varicella among others. The market is expected to grow on average 8% per year.
Maintaining a cold chain that doesn’t break at any point can become a very challenging quest when power outages are common. When there’s a lack of adequate temperature monitoring there’s no way to predict when the potency of vaccines has been compromised by previous breaks in the cold chain, causing undesirable and sometimes harmful results. The Zika virus is doing enough damage as-is. Do we need to cause further harm by vaccinating those living in affected areas with a damaged vaccine and diminishing the chance of eliminating the epidemic? With time on our side for once, it’s imperative that all agencies and companies involved in the treatment and further spread of the Zika virus work together now to build a strong, reliable, and effective cold chain to ensure the effective distribution of the Zika vaccine.