Before being applied to vaccines, MVVs should be stored at temperatures <-24°C and kept away from light and other sources of radiation. After application to vaccines, storage conditions are based on vaccine storage requirements. This specification describes the general performance requirements for the vaccine vial monitor (VVM). The Joint Policy Statement calls on all WHO countries and Member States with access to self-purchased vaccines to use VMVs and minimum requirements for vaccine purchase contracts. The Declaration recommends that all Member States adopt vaccine management practices that include: "The Joint WHO-UNICEF Policy Statement stresses the need for a steady supply and calls on all Member States to include VVM in the minimum requirements for all vaccines procured. It also urges donors to adopt a policy that specifically requires MVVs to be included as a minimum standard in every vaccine donation," Kartoglu said. – by Pam Rothman The Vaccine Fial Monitor is not affected by freezing temperatures, as it only reacts to heat surges. The study showed that exposure of the vaccine to abnormal temperatures was associated with the absence of an alternative power supply. To solve this problem, every vaccination facility in the Northwest region must have at least two sources of energy. The VVM is represented by a circle with a small square inside, printed on a product label attached to the cap of the vaccine tube or around the neck of a blister. It contains a light-sensitive heat-sensitive material in the form of an inner square, which becomes darker when exposed to heat. A vaccine vial monitor (VVM) is a thermochromic label that is affixed to vaccine vials and provides a visual indication of whether the vaccine has been stored at a temperature that preserves its effectiveness.
The labels were developed in response to the problem of vaccine supply in developing countries where the cold chain is difficult to maintain and where vaccines were previously rendered inactive and ineffective because they were denatured by exposure to ambient temperature. In the 1970s, PATH began working with WHO to develop a system for identifying vaccines that had expired due to improper storage. In 1996, the vaccine vial monitor was first used in a vaccine project, and the following year it was widely accepted for use in many vaccine projects. [ref. necessary] [WHO_PQS_E006_IN05-VP.4] Vaccine Vial Monitor Independent Testing Protocol There are four different types of MVV for some vaccines, which are: It is important to note that vaccine vial monitors do not alter the heat tolerance of the vaccine, but only indicate heat exposure. The study concluded that exposure to vaccines at suboptimal temperatures is a global problem and is well documented in many parts of the world. Vaccine vial monitors contribute to the effective management of the pharmaceutical cold chain, especially in the field. Health care workers may choose vials with minimal exposure for use. The study showed that 24% of vaccine refrigerators exposed vaccines to suboptimal temperatures within two months. The problem of overheating was documented in all refrigerators exposed to suboptimal temperatures, while only 67% of them were exposed to temperatures below freezing. The absence of an alternative energy source was associated with exposure of the vaccine to suboptimal temperatures.
• Know if health workers are correctly interpreting VVM readings The concept of MVV was conceived by WHO in 1979. The first vaccine to be tested with VVM was the measles vaccine the same year with a p-toluenesulfonate chemical, for which development of the product began under the Appropriate Health Technologies Program (PATH). At that time, the target price for FMVs was 5 cents. [WHO_PQS_E006_IN06.1] Performance specification for combined VVM threshold indicators To measure VVMs, place the VVMs with the release liner always mounted on white cardboard, and then measure the optical density (OD) of the active indicator (I) and reference ring (R) using an X-Rite 500 series spectral densitometer or equivalent. Measure the reference ring by taking one measurement from the bottom of the ring and a second measurement from another point 90° away. Measure the active indicator by taking two measurements from different points in the active square. To determine the difference in optical density, also known as R-I, subtract the mean value I from the average value R. VMMs also allow managers to track locations with unstable cooling systems based on meter density. They can check the effectiveness of thermal systems if they detect the change in density during transport or storage. Researchers conducted a study in Cameroon to document the effects of vaccine exposure on adverse temperatures.
As a resource-limited tropical country, Cameroon`s pharmaceutical cold chain is exposed to fluctuating storage temperatures. A total of 65 health facilities from eight health districts were visited for the study. Of the health facilities, 48 (73.8%) were public institutions. About 50 (76.0%) of the facilities had a functional thermometer. Of the 50 health facilities equipped with a functional thermometer, unusual temperatures were recorded in 10 (20%) health facilities during data collection and 12 (24%) in the 2 months prior to the survey. Another factor significantly associated with abnormal temperature records was the lack of an alternative energy source. Originally, WHO and UNICEF issued a joint policy statement in 1999 on the use of VVM with all vaccines. At a meeting the same year, UNICEF announced that MVVs would be included in all vaccines from the year 2000. However, in 2001, only three UNICEF vaccine providers used violence protection devices with vaccines. In 2005, 12 other UNICEF vaccine suppliers were using VVM accessories. Vaccine Vial Surveillance Protocols and Evaluation Vaccine vial monitors (VVMs) are used to alert health workers when a vaccine has been heat damaged.
The monitor is made of a heat-sensitive material that is shiny but darkens when exposed to heat over time, indicating that the vaccine is no longer effective. Studies have shown that without proper training, health workers sometimes do not understand what VVM is or how it works. A 2007 study in the urban areas of Valsad, India, showed that vaccine managers were unaware of the monitors` purpose. [5] The Vaccine Fials Monitor is intended for use with vaccines that may migrate outside the cold chain, but its use on some vaccines has had particularly notable effects. [ref. needed] Since 1997, nearly 2 billion units of MVV with vaccines have been used, celebrating 10 years of implementation. In addition, the price of MVVs is still around 5 cents, according to WHO scientist Ãmit Kartoglu, MD, DPH. Health workers test each batch of vaccine vial monitors twice to ensure they respond correctly to heat exposure.
They do the first test before shipping from the factory. Manufacturers perform the second before shipment. Medical technicians use color-reflecting densitometers to test vaccine vial monitors. The following graph shows the changing appearance of MVV when exposed to heat over time: MVV is an essential part of vaccine manufacturers` ability to provide life-saving vaccines to support global immunization programs. Through simple, predictable, reliable and visual color changes, healthcare workers know at a glance if a vaccine has been exposed to potentially harmful heat. Irreversible time-temperature indicators can play a crucial role in the success of immunization programs worldwide. A vaccine vial monitor (VVM) is defined as “a label containing heat-sensitive material placed on a vaccine vial to record cumulative heat exposure over time.” The VVM is placed on a vaccine vial by the vaccine manufacturer to allow for lifetime thermal monitoring. It allows health care professionals to administer vaccines knowing that the vaccine has not been exposed to potentially harmful heat. Even if a vaccine has been subjected to an accidental heat excursion, the VVM provides a visual clue as to whether the vaccine can still be used and its use can help reduce waste and increase coverage. At the very least, MVVs can prevent the use of exposed vaccines, thereby protecting recipients from health risks. The simple technology applied to VVM fills a big gap in the pharmaceutical cold chain, especially in countries where refrigeration and power supply are problematic. Vaccine vial monitors are additional costs that affect the price of vaccines.
However, the increase in costs is offset by the reduction of waste, health risks and inefficiencies in cold chain management. To read a VVM, compare the color of the inner square with the color of the outer circle: the vaccine should be discarded when the inner square becomes as dark as the outer circle. This means that the vial has been exposed to unacceptable heat. Once the darkness of the inner square is equal to or darker than the outer circle, health workers should discard the vaccine. When international standards for vaccine supply were written in the 1970s, manuals generally generalized the care needs for oral polio vaccine, as it was the most sensitive vaccine widely available. [1] The use of impotent vaccines is life-threatening because they can have health effects on their recipients.
