Since 2010, numerous new technologies have entered the immunization cold chain equipment market. The World Health Organization (WHO) Immunization Devices Programme-Performance, Quality and Safety (PQS)-has played a key role in bringing these to market. In this article, the authors explore the emergence of new cold chain equipment technologies from 2004 to 2016 and the role of PQS in this evolution. This review focuses on three major vaccine cold chain technology innovations-solar direct-drive refrigerators, long-term passive cold boxes, and equipment with user-independent freeze prevention. For the review, we used online data from WHO PQS, a literature search, and unpublished research reports. Timelines with key milestones in the emergence of the three focus technologies show delays of between one and three years between earliest field trials and publication of WHO specifications; procurement builds after the WHO prequalification of initial devices. The timelines show the role of PQS as both gatekeeper and enabler for cold chain equipment technologies. The use of target product profiles by PQS has increased its ability to signal preferred attributes and to engage with manufacturers during the product-development stage. Procurement data show how demand for solar direct-drive refrigerators increased over time. Gavi, the Vaccine Alliance, is employing demand-generation strategies to try to drive procurement of technologies with favorable technical attributes.

Vaccine cold chain equipment (CCE) in developing countries is often exposed to harsh environmental conditions, such as extreme temperatures and humidity, and is subject to many additional challenges, including intermittent power supply, insufficient maintenance capacity, and a scarcity of replacement parts. Together, these challenges lead to high failure rates for refrigerators, potentially damaging vaccines and adversely affecting immunization coverage. Providing a sustainable solution for improving CCE performance requires an understanding of the root causes of failure. Project teams conducted small-scale studies to determine the root causes of CCE failure in selected locations in Uganda and Mozambique. The evaluations covered 59 failed refrigerators and freezers in Uganda and 27 refrigerators in Mozambique. In Uganda, the vast majority of failures were due to a cooling unit fault in one widely used refrigerator model. In Mozambique, 11 of the 27 problems were attributable to solar refrigerators with batteries that were unable to hold a charge, and another eight problems were associated with a need to adjust thermostat settings. The studies showed that tracking and evaluation of equipment performance and failure can yield important, actionable information for a range of stakeholders, including local CCE technicians, the ministry of health, equipment manufacturers, and international partners such as the United Nations Children's Fund, World Health Organization, and Gavi, the Vaccine Alliance. Collaborative efforts to systematically collect and communicate data on CCE performance and causes of failure will help to improve the efficiency and reach of immunization programs in low- and middle-income countries.

Vaccine procurement costs comprise a significant share of immunization program costs in low- and middle-income countries, yet not all procured vaccines are administered. Vaccine wastage occurs due to vial breakage, excessive heat or freezing, expiration, or when not all doses in a multidose vial are used. Better estimates of vaccine wastage rates and their causes could support improved management of vaccine stocks and reduce procurement costs. This study examined aspects of wastage for four vaccines at service delivery points in Ghana (n = 48), Mozambique (n = 36), and Pakistan (n = 46). We used prospective data from daily and monthly vaccine usage data entry forms, along with cross-sectional surveys, and in-depth interviews. The analysis found that estimated monthly proportional open-vial wastage rates for vaccines in single-dose vials (SDV) or in multi-dose vials (MDV) that can be kept refrigerated up to four weeks after opening ranged from 0.08 % to 3 %. For MDV where remaining doses are discarded within six hours after opening, the mean wastage rates ranged from 5 % to 33 %, with rates being highest for measles containing vaccine. Despite national-level guidance to open a vaccine vial even when only one child is present, vaccines in MDV that are discarded within six hours of opening are sometimes offered less frequently than vaccines in SDV or in MDV where remaining doses can be used for up to 4 weeks. This practice can lead to missed opportunities for vaccination. While closed-vial wastage at service delivery points (SDPs) was relatively rare, individual instances can result in large losses, suggesting that monitoring closed-vial wastage should not be neglected. Health workers reported insufficient knowledge of vaccine wastage tracking and reporting methods. Improving reporting forms would facilitate more accurate reporting of all causes of wastage, as would additional training and supportive supervision. Globally, decreasing doses per vial could reduce open-vial wastage.

As part of the Vaccine Innovation Prioritisation Strategy (VIPS), three immunization-stakeholder consultations were conducted between September 2018 and February 2020 to ensure that countries' needs drove the prioritization of vaccine product innovations. All consultations targeted respondents with immunization program experience. They included: (1) an online survey to identify immunization implementation barriers and desired vaccine attributes in three use settings, (2) an online survey to identify and evaluate the most important immunization challenges for ten exemplar vaccines, and (3) in-depth interviews to better understand the perceived programmatic benefits and challenges that could be addressed by nine innovations and to rank the innovations that could best address current challenges. The first consultation included responses from 442 participants in 61 countries, representing 89% of the 496 respondents who correctly completed at least one section of the online survey. For facility-based settings, missed opportunities for vaccination due to reluctance to open multidose vaccine vials was the barrier most frequently selected by respondents. In community-based (outreach) and campaign settings, limited access to immunization services due to geographic barriers was most frequently selected. Multidose presentations with preservative or single-dose presentations were most frequently selected as desired vaccine attributes for facility-based settings while improved thermostability was most frequently selected for outreach and campaign settings. The second online survey was completed by 220 respondents in 54 countries. For the exemplar vaccines, vaccine ineffectiveness or wastage due to heat or freeze exposure and missed opportunities due to multidose vial presentations were identified as the greatest vaccine-specific challenges. In-depth interviews with 84 respondents in six countries ranked microarray patches, dual-chamber delivery devices, and heat-stable/controlled temperature chain qualified liquid vaccines as the three innovations that could have the greatest impact in helping address current immunization program challenges. These findings informed the VIPS prioritization and provided broader application to designing immunization interventions to better meet country needs.

SARS-CoV-2 vaccines will be deployed to countries with limited immunization systems. We assessed the effect of deploying SARS-Cov-2 vaccines on cold storage capacity and immunization workload in a simulated WHO African Region country using region-specific data on immunization, population, healthcare workers (HCWs), cold storage capacity (quartile values for national and subnational levels), and characteristics of an approved SARS-CoV-2 vaccine. We calculated monthly increases in vaccine doses, doses per vaccinator, and cold storage volumes for four-month SARS-CoV-2 vaccination campaigns targeting risk groups compared to routine immunization baselines. Administering SARS-CoV-2 vaccines to risk groups would increase total monthly doses by 27.0% for ≥ 65 years, 91.7% for chronic diseases patients, and 1.1% for HCWs. Assuming median nurse density estimates adjusted for absenteeism and proportion providing immunization services, SARS-CoV-2 vaccination campaigns would increase total monthly doses per vaccinator by 29.3% for ≥ 65 years, 99.6% for chronic diseases patients, and 1.2% for HCWs. When we applied quartiles of actual African Region country vaccine storage capacity, routine immunization vaccine volumes exceeded national-level storage capacity for at least 75% of countries, but subnational levels had sufficient storage capacity for SARS-CoV-2 vaccines for at least 75% of countries. In the WHO African Region, SARS-CoV-2 vaccination campaigns would substantially increase doses per vaccinator and cold storage capacity requirements over routine immunization baselines. Pandemic vaccination campaigns would increase storage requirements of national-level stores already at their limits, but sufficient capacity exists at subnational levels. Immediate attention to strengthening immunization systems is essential to support pandemic responses.

Background: Influenza vaccination is uncommon in low-resource settings. We evaluated aspects of operational feasibility of influenza vaccination programs targeting risk groups in the World Health Organization (WHO) African (AFR) and South-East Asian (SEAR) Regions. Methods: We estimated routine immunization and influenza vaccination campaign doses, doses per vaccinator, and cold storage requirements for 1 simulated country in each region using evidence-based population distribution, vaccination schedule, and vaccine volumes. Influenza vaccination targeted persons <5 years, pregnant women, persons with chronic diseases, persons ≥65 years, and healthcare workers (HCW). For the AFR country, we compared vaccine volumes to actual storage capacities. Results: Targeting HCW had a small operational impact, and subsequent findings exclude this group. During 3-month influenza vaccination campaigns, monthly doses delivered in the AFR country increased from 15.0% for ≥65 years to 93.1% for <5 years and in the SEAR country from 19.6% for pregnant women to 145.0% for persons with chronic diseases. National-level cold storage capacity requirements increased in the AFR country from 4.1% for ≥65 years to 20.3% for <5 years and in the SEAR country from 3.9% for pregnant women to 28.8% for persons with chronic diseases. Subnational-level cold storage capacity requirements increased in the AFR country from 5.9% for ≥65 years to 36.8% for <5 years and the SEAR country from 17.6% for pregnant women to 56.0% for persons with chronic diseases. Conclusions: Influenza vaccination of most risk groups will require substantial increases in doses, doses per vaccinator, and cold storage capacity in countries where infrastructure and resources are limited.