What are the challenges and solutions to the cold chain last-mile delivery?Last-mile delivery is the most crucial part of the cold chain, yet it’s also the most difficult. Delivering vaccines to far-flung, resource-poor health centers requires more than just the ability to transport products. Most of the time, delivery locations are remote, without internet or cellular connections. Even after the vaccines are delivered, unreliable and unstable electricity may spoil their potency. The “last mile” is where district health centers deliver vaccines to rural health centers across the country. This is typically the weakest link in the supply chain due to lack of infrastructure, insufficient technical capability, and overburdened personnel. Through the help of organizations, such as Village Reach, these problems are slowly being addressed with new ideas, innovations, and solutions.

Challenges to the Last-Mile

Insufficient equipment and infrastructure

The inability to connect to stable electricity is one barricade to a successful cold chain. While the use of passive cooling devices will temporarily do their job, refrigerators and freezers for cooling the coolant packs used in the devices will always be needed. Without them, passive containers will only maintain their temperatures for a short time. In additions to that, data management may also be inefficient. Without electricity, there’s no chance of accessing the central data system for storing temperature and tracking data.

Even if there is electricity, some remote areas experience sporadic and frequent power outages, which are damaging to the refrigeration systems housing the vaccines. As a result, vaccines may become less effective.

Moreover, cold chain infrastructure has attracted less investment than the vaccines. The World Health Organization (WHO) estimates that about 200 million dollars are needed per year to address cold chain problems in developing countries.

Source: vilagereach.org

While solar refrigerators can compensate for the loss of electricity connection, they are marred with problems. Batteries need to be replaced every five years, thus requiring robust maintenance and extra budget allocations. Staff in remote areas also lack technical knowledge in installation and maintenance of the solar devices.

Although vaccine vial monitors (VVM) help indicate heat exposure, they are less useful in reporting freezing events, an occurrence that is more common and more damaging to vaccines.

Adherence to appropriate vaccine stock management practices

Overstocking of the available refrigerators is a common problem in management practices. It violates the earliest-expiry-first-out (EEFO) principle and runs the risk of vaccine wastage due to improper observation of the expiration date. Additionally, overstocking can elevate the temperature above 8°C (46°F) or cause dips below 2°C (35°F).

Having high-staff turnover impedes knowledge of adherence to stock management and cold chain maintenance. Frequently, new personnel do not receive proper training. In turn, they are insufficiently informed to be able to follow guidelines or take action on some problems.

Health personnel may also neglect the protocol of monitoring vaccine temperature twice-a-day. They may only do so during supervisor visits, defeating the purpose of regular temperature monitoring.

Insufficient technical personnel

In Mozambique, for instance, in 2020 there is only one technician employed by the Provincial Directorate of Health (Direcção Provincial de Saúde – DPS) who is responsible to maintain and repair cold chain technical problems for more than 100 health centers, 10-15 district-level refrigerators, and all of the provincial-level cold storage facilities. With the introduction of the new vaccines Rotarix and HPV, the Mozambique health center will receive yet another overwhelming volume of vaccines. Those vaccines will require another set of equipment and storage systems to maintain and monitor them. With only limited human resources, the situation may produce new problems to overcome.

Solutions to the Last Mile Challenges

Village Reach provides solutions to these last-mile problems by employing the Dedicated Logistics System (DLS)

approach. This approach is a simple way of integrating maintenance activities with cold chain activities. This approach goes beyond normal maintenance when the problem arises, but provides preventive maintenance. Field coordinators, normally tasked in distributing vaccines across levels of the cold chain, will also be trained in the skills of preventive measures and maintenance.

Field coordinators will tour health centers more frequently than the main technicians. They will be the extended arms and eyes of the main technicians, whose work will then deal with tougher maintenance problems. This is different from traditional cold chain set ups where responsibility for data management and maintenance rests at the district and national levels. The DLS approach extends these scarce skills to the last mile.

These are the tasks of the field coordinators for basic preventive maintenance in their distribution visits:

  • Monitor the temperature of the vaccines by checking the refrigerator thermometer to ensure it is working in the optimal range.
  • Ensure that the refrigerator not being used for personal storage by the staff.
  • Verify that the distance between the refrigerators and the walls should be safe and allow for air circulation to prevent overheating of the engine and breakdown of the machine.
  • Check that the temperature monitoring form is updated every day, and not just during visits.
  • Ensure adequate power supply to all machines and devices used for vaccine storage.
  • Consider the ambient temperature (seasons and weather) and then regulate the refrigerators’ temperature to prevent temperature anomalies.
  • Prevent overstocking of vaccines to ensure better airflow and to easily dispose of vaccines nearing expiration dates. 
  • Provide technical assistance to health workers and educate them on basic preventive measures.

In addition to preventive measures, corrective measures need to be considered in case all prevention fails. Corrective action is the responsibility of the field coordinators and the main technicians. Health center staff must call them immediately when there are technical problems that should be addressed only by a technician.  Problems may include changing a fuse or replacing a battery for solar refrigerators, or the replacement of the whole device. Field coordinators work and collaborate with the cold-chain maintenance team who work on more than 100 health care across the country. In the case of poor-resource locations, the field coordinator may be a one-man team.

Global innovations for the last mile

Supply-chain manufacturers have been developing devices to cope with problems of electricity reliability, high-maintenance requirements, and storage capacity. Passive cooling technologies have become more common for vaccine storage because of their ability to function via alternate power sources such as gas, kerosene, or solar panels where reliable electricity sources are scarce.

In our previous articles, we discussed new technologies currently being studied and demonstrated by manufacturers with the help of NGOs such as PATH and WHO. By becoming WHO prequalified, the technologies are some of the most innovative ways to deliver vaccines to places where electricity access is a problem.

Improved data management is one aspect that will greatly improve the cold chain industry. Using telematics and telemetry will enhance the lines of communication from the national centers to remote health centers of the region.

In many developed countries, telemetry is a mature commercial marketplace, constituting a 40-billion-dollar industry. Several sectors include telemetry in the monitoring of their cold chain equipment, inventory management, asset tracking, and infrastructure assessment

In Mozambique, Village Reach will be implementing the Cold Trace, developed by Nexleaf. This software system remotely monitors the temperature of cold chain equipment and transfers the data gathered, via telemetry, to the national health centers for analysis.

The cold chain has seen many developments in past decades. There are numerous passive cooling technologies currently manufactured with more being developed to tackle electricity problems with storage. Sophisticated data systems are being incorporated into the cold chain from several industries, to monitor the equipment of far-flung parts of any country.

As immunization programs widen their reach and more people are being free from deadly diseases, the cold chain is becoming increasingly sophisticated. With that increased sophistication are new sets of problems, from technical aspects to general information on handling vaccines. The goal, however, stays the same, immunize as many people as possible. The development of vaccines has led to the eradication of several deadly diseases. In delivering quality vaccines, the cold chain plays a vital part.




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