Vaccine Vial Monitor Systems Critical in Polio Eradication Effort

Monitors alert health workers when a vaccine has potentially been compromised by cold chain failures.

Monitors alert health workers when a vaccine has potentially been compromised by cold chain failures.

As of May 21, 2015, only 2 dozen cases of polio have been reported worldwide this year.

Of these cases, all but 1 occurred in Pakistan. With the push to eradicate polio entirely nearing the finish line, it is vital for all vaccines administered at this critical time to have full protective activity. Given that the polio vaccine is heat-sensitive, cold chain monitoring is important in ensuring vaccine potency.

According to the US Centers for Disease Control (CDC), polio is still a public health concern in certain countries, such as Afghanistan, Nigeria, and Pakistan. The Global Polio Eradication Initiative (GPEI) is an ongoing initiative funded by several national governments, as well as private organizations such as the CDC, Rotary International, UNICEF, the Bill & Melinda Gates Foundation, and the World Health Organization (WHO).

The WHO uses a technology called a vaccine vial monitor (VVM) system to help ensure the potency of vaccines. WHO representatives noted at the 2008 meeting that only one company in the world—TempTime Corporation—manufactures these VVMs, and has production capacity that is sufficient to manufacture more than 7 billion VVM systems each year. As a result of this substantial production capacity, TempTime is able to provide the VVM system at the extremely low cost of approximately 5-cents per monitored vial.

Vaccine vial monitors are small heat-sensitive stickers with thermochromic properties, which means it changes color when vaccines are exposed to heat. In this way, the stickers alert health workers when a vaccine has potentially been compromised by cold chain failures. Because the color change is irreversible, thermochromic stickers continue to report out-of-range temperatures even if the temperature returns to normal. VMMs are instrumental in immunization efforts, especially in remote areas, and have been a key technology in facilitating the global campaign toward polio eradication.

The VVM system is already used around the world, from Africa to the Eastern Mediterranean. However, surprisingly, many middle-income countries and world regions do not use VMMs under the assumption that infrastructure such as refrigerators and constant electrical supply will protect vaccines from cold chain errors.

These assumptions have proved inaccurate in many cases. Even in middle-income and high-income countries, vaccines may be exposed to out-of-range temperatures, potentially compromising their efficacy. In one study, researchers linked out-of-range temperatures at freezers in certain population areas of Houston, Texas with higher rates of vaccine-preventable illness, which suggests that inadequate cold chain procedures may be harming public health.

Around the world, VMMs are projected to reduce the costs and improve the efficacy of immunization programs. Over the coming decade, the WHO estimates that VMMs will help health care workers detect 368 million doses of inactive vaccines that would otherwise have been administered to patients, enabling delivery of 1.5 billion doses of vaccines to remote areas, and saving an estimated 140,000 lives. Due to these many benefits, the WHO will not purchase vaccines that are not equipped with VMMs.

In the United States, use of VMMs is growing, as many manufacturers and specialty pharmacies are using these systems to safeguard product quality and public health. Across specialties, physicians are concerned about the risks of heat-damaged pharmaceutical products. Sixty percent of physicians rate their level of concern regarding heat stability as “very concerned,” and most physicians—up to 70% in some surveys—have experienced breaks in the cold chain first hand. These inexpensive safeguards help protect the US supply chain, prevent cold chain failures that may lead to outbreaks of vaccine-preventable illness, and aid health care workers as a mission-critical technology in the campaign to eradicate polio from the planet.


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