Switching from 10-dose to using 5-dose measles-containing vaccine vial presentation: lessons from 7 countries in the WHO African Region

¹World Health Organization, Regional office for Africa, Brazzaville, Republic of Congo, ²Linksbridge SPC, Seattle, Washington, United States of America, ³World Health Organization, Inter-country team for Western Africa, Ouagadougou, Burkina Faso, ⁴World Health Organization, Inter-country Team for Central Africa, Libreville, Gabon, ⁵World Health Organization, Inter-country Team for Eastern and Southern Africa, Harare, Zimbabwe

^&Corresponding author
Balcha Girma Masresha, World Health Organization, Regional office for Africa, Brazzaville, Republic of Congo

Introduction    

In 2023, nearly 35 million children worldwide missed at least one dose of the measles-containing vaccine (MCV), leaving them vulnerable to severe illness and death [1]. The World Health Organization (WHO) estimated over 107,000 measles-related deaths occurred globally that year, primarily among unvaccinated children under five years old [2]. Notably, just 10 countries, including five in Africa, accounted for 57% of all infants missing the first MCV dose (MCV1) [3]. The WHO African Region has set the goal of eliminating measles and rubella in over 80% of countries in the Region by 2030. This includes achieving MCV1 and MCV2 vaccination coverage rates of at least 95% [4]. Strengthening routine health systems through these targets will require collective effort, particularly addressing the operational and behavioral barriers that lead to missed opportunities for vaccination [3].

Routine immunization programs in low- and middle-income countries are often resource-constrained and supported by global partners for vaccine procurement. These countries rely on multidose MCV vials to vaccinate multiple children per session. Until recently, the majority of countries in Africa used 10-dose MCV vials (including measles-only and Measles-Rubella formulations) in routine immunization [5]. For safe handling, reconstituted lyophilized vaccine vials including MCV, the yellow fever (YF) vaccine, and the Bacillus Calmette-Guérin vaccine (BCG) must be discarded six hours after opening or at the end of an immunization session, whichever comes first [6]. This short window of utilization of reconstituted vaccines means that, when a health worker opens a 10-dose vial for only a few children, there is a high risk of wastage of vaccines doses, leading to stock imbalances and reduced availability for future sessions. As a result, health workers are often reluctant to open vials outside of high-attendance sessions, even when national policies permit it. This can lead to children being turned away, leading to missed opportunities for vaccination, delayed immunization, and persistent gaps in population immunity. Sustained coverage gaps undermine efforts to prevent outbreaks and eliminate measles, especially in underserved areas [5]. A modeling study found that opening 10-dose vials when at least 30% of doses would be used offers the most cost-effective balance between availability and efficiency [7]. However, implementing this threshold is challenging in practice. In many settings, 5-dose vials offer a more feasible and pragmatic alternative to reduce missed opportunities and improve the timeliness of vaccination. There is substantial qualitative evidence about health worker hesitancy to open 10-dose vials and related missed vaccination opportunities. A study in Zambia designed to measure the impact of a switch to a smaller vial size on MCV coverage and vaccine wastage showed that districts using 5-dose vials had 47% lower wastage, 4.9% higher first-dose coverage, and 3.5% higher second-dose coverage compared to those using 10-dose vials [8]. Subsequent findings from other countries have reinforced this evidence, linking 5-dose vials to more frequent vaccination sessions, improved timeliness, better MCV1 and MCV2 coverage, reduced wastage, and even lower procurement costs [9-11]. Despite this growing body of evidence, the adoption of fewer-dose vials in Africa remains limited, underscoring the need for stronger advocacy, clearer policy guidance, and targeted implementation support [12].

In 2020, the African Regional Immunization Technical Advisory Group (RITAG) recommended adopting fewer-dose MCV vials as part of a broader strategy to increase vaccination coverage, reduce wastage, and address health worker reluctance to open 10-dose vials [13]. WHO AFRO has set an operational target for 70% of countries in the Region to implement this switch by 2030. As of June 2025, the number of countries using MCV 5-dose or fewer-dose vials had increased from 8 (~17%) before 2020 to 17 (~36%), with Ethiopia and Nigeria planning to switch to 5 dose vials by early 2026. As more countries plan switches to fewer-dose vials, there is an urgent need to understand what drives successful implementation. This report presents qualitative and preliminary findings from several countries in the African Region that switched from 10-dose to 5-dose vials for routine measles and rubella immunization over the past decade. It examines the implementation processes, evaluates the observed outcomes of these transitions, and identifies the gaps and challenges encountered.

Methods     

This study used a mixed methods approach to explore the operational and programmatic experiences of seven countries that transitioned from 10-dose to 5-dose MCV vials. This included a review of available program documentation and data, as well as the interviews with program staff at national and subnational levels. The countries assessed Democratic Republic of Congo (DRC), Equatorial Guinea, Eswatini, Lesotho, Niger, Togo, and Zimbabwe, had each completed the switch as part of their national immunization strategies.

At the time of data collection, except for standardized guidelines and tools for the evaluation of new vaccine introduction, no specific standard guidelines existed to evaluate the switch from 10-dose to 5-dose vials. In response, the co-authors of this study developed a regionally tailored implementation review protocol to provide a structured framework for formal assessments. This protocol was applied in Eswatini and Lesotho, where desk reviews, site visits to districts and health facilities, and interviews with national and subnational immunization stakeholders were conducted. In addition, the review found no standardized global or national checklists for the switch, and it did not systematically assess the availability or use of country-developed tools.

Data collection occurred between 2023 and 2025 and consisted of desk research and review of official reported data through the WHO/UNICEF Joint Reporting Form on Immunization (JRF) , formal in-person assessments, virtual interviews, and email correspondence. At least one key informant interview was conducted per country, primarily with national immunisation program managers. A total of 12 national and provincial-level in-person interviews were completed in Lesotho, and 18 interviews were done in Eswatini. Five virtual interviews were conducted with focal persons in DR Congo, Equatorial Guinea, Niger, Togo, and Zimbabwe, and in all five of these countries, email correspondence was used to supplement and clarify the information obtained.

Two interview tools were used. For formal field assessments, WHO AFRO applied a structured interview guide from the protocol, which covered areas related to decision-making, preparation, roll-out, and service delivery. A shortened and semi-structured version of this guide was used for virtual interviews to accommodate time constraints while maintaining consistency in thematic focus. Both instruments were internally validated through pilot testing with WHO AFRO technical teams and refined based on feedback to ensure clarity and relevance. Virtual interviews, each lasting approximately one hour, were conducted via Microsoft Teams. With participant consent, they were recorded, transcribed verbatim, and summarized. Email responses were documented and coded thematically. All data were analyzed using a framework analysis approach aligned with the review protocol´s domains, and findings were synthesized to identify recurring themes, country-specific practices, and key insights related to the implementation of the 5-dose MCV switch.

Results     

Democratic Republic of the Congo (DRC)

Rationale, national policy and guidelines: the switch to 5-dose measles monovalent vaccine vials was necessitated to reduce the vaccine wastage rate, to reduce missed opportunities for vaccination and to increase measles vaccination coverage. A calculation of the cost and cold chain space needs was done before the decision to switch to 5-dose presentation. The national policy does not state a specific number of children required to open MCV 10-dose vials. However, it was common practice at health facility levels to wait for 6-8 children during vaccination sessions before opening vials. Health workers were concerned about high wastage rates, so measles vaccination was not provided in all sessions, but only on appointed days. The current policy of DRC is to increase the number of vaccination sessions and provide services using all antigens in all sessions, including measles vaccines.

Process of switching to 5-dose vials: DR Congo switched to using 5-dose measles vials in 2022 following the National Immunization Technical Advisory Group´s (NITAG) recommendation to switch. The country developed guidelines and started communicating with health workers in 2021. The switch was done in a short period as part of a scheduled MCV2 introduction. The health worker training was implemented at the time of the MCV2 introduction and the launch of the 5-dose vials. The country had benefited from a cold chain space expansion since 2018, and at the time of the switch, did not have any problem accommodating the 5-dose vials at all levels. The country received Gavi funding for the 5-dose vial switch and used it to orient health workers, to implement post-introduction supervision, and to update data tools for MCV2 introduction. Supervisory visits were done shortly after the switch.

Vaccination service delivery: The MCV 5-dose presentation is very well received by health workers. Health workers now open 5-dose vials with 1 or 2 children at vaccination sites, with reduced fear of incurring high wastage rates. Based on this experience, health workers request similar 5-dose presentations for other antigens like the YF vaccine. Administrative coverage data, as reported during the interviews, indicate that national MCV1 coverage increased from 84% in 2021 to 95% in 2024. For MCV2, administrative coverage rose sharply from 15% in 2023 to 65% in 2024. No challenge was noted with the cold chain space. However, the increased frequency of vaccine supply deliveries to health facilities due to the change in vial size was not factored into the operational costing of the switch, and is recommended for consideration by other countries.

Equatorial Guinea

Rationale, national policy and guidelines: The decision to switch was made to address persistent challenges associated with the use of 10-dose vials, including high vaccine wastage rates, low vaccination coverage, and a high number of missed opportunities for vaccination. Before the switch to 5-dose vials, measles vaccines were typically administered only on scheduled monthly immunization days at almost all health facilities. The adequacy of cold chain space was verified before the switch to 5-dose vials, based on the findings of a cold chain assessment conducted in 2017. There is no written policy regarding the frequency of vaccine delivery or the minimum number of children required to open vaccine vials.

Process of switching to 5-dose vials: The country transitioned from the 10-dose to 5-dose measles monovalent presentation beginning in 2018. The NITAG was not involved in the decision-making process. There was no targeted sensitization and training done for health workers, but they were informed about the change through supervisory visits. No operational or programmatic challenges were noted during the switch process or after the implementation. Initial reporting challenges following the switch were reportedly resolved within a few months. As a non-Gavi-eligible country, the national program pays for all vaccines and utilizes the UNICEF vaccine procurement mechanism. The higher cost associated with 5-dose vials was recognized, but there was no challenge in securing government resources for the switch.

Vaccination service delivery: Following the switch to 5-dose vials, health workers now offer measles vaccination once a week instead of once or twice monthly, despite national guidelines recommending daily availability, due to low client turnout at vaccination sites. Some districts insist that parents and caregivers know the fixed weekly vaccination schedule and do not conduct daily vaccination sessions. According to the EPI team, the shift to 5-dose vials led to a notable reduction in vaccine wastage and perceived improvements in MCV1 coverage. However, administrative data show no significant change in MCV1 coverage since the switch. The country provides MCV2 at 18 months of age, but is considering changing the schedule to provide MCV2 at 15 months to ensure better uptake.

Eswatini

Rationale, national policy, and guidelines: The switch to 5-dose MR vials was implemented when the country moved from private sector vaccine procurement to UNICEF procurement mechanisms. The national vaccination policy document states that health workers should prioritize and open vials of MR vaccine even if there is one eligible child. The national immunization guidelines include the 5-dose MR vial and use an average of 60% wastage rate as the basis for vaccine forecasting and supply planning.

Process of switching to 5-dose vials: The switch to 5-dose MR vials was implemented in 2019 over a short period of time, and was done with little official communication, guidance, or training. The NITAG was not involved in the decision, and there was no switch plan developed. No calculation or expansion of the cold chain space was done in preparation for the switch. MR 10-dose vials were used up in outreach sites before the distribution and use of 5-dose vials started. In at least one region, 10-dose vials were recalled to the central level before health facilities started using 5-dose vials. After the introduction, there was no major challenge with cold chain space to accommodate 5-dose MR vials. Beyond the usual supervisory visits, there was no post-switch assessment to review the process and address any issues.

Vaccination service delivery: Vaccination services (including for MR vaccines) were consistently provided 5 to 6 days per week at all health facilities in the sites visited and this practice continued following the switch to 5-dose MR vials. There is a broad consensus that the switch to 5-dose vials contributed to reduced vaccine wastage and that MR coverage remained high across all districts.

Lesotho

Rationale, national policy, and guidelines: The country decided to switch to 5-dose MR vials based on the observation that health workers were hesitating to readily open 10-dose vials during vaccination sessions and learning that 5-dose vials were available in the market. The additional costs, as well as the expected coverage improvement and reduction in vaccine wastage rates, were also considered in the decision-making process. The national immunisation policy and program plan documents, as well as recent program review reports, did not include any information on the switch from 10- to 5-dose MR vials. There is no written policy on the minimum number of children to open vaccine vials.

Process of switching to 5-dose vials: The 5-dose vial switch was implemented starting in July 2019 and was completed progressively over several months. The NITAG was not involved in the decision-making process, and no formal plan was drafted to guide the switch. No cold chain assessment was undertaken in preparation for the switch because the country was already in the process of upgrading the cold chain system at all levels of the health system. Health facilities were requested to deplete their 10-dose legacy vials before transitioning to 5-dose vials. An official communication about the switch was sent to subnational immunization program focal persons, but no formal training was conducted. However, on-the-job sensitization was done during the delivery of 5-dose vials to districts and health facilities and during supportive supervisory visits. There was no modification of the existing immunization program tools at the time of the switch. There was no post-switch assessment to review the process and address any issues. During the switch, national program funds were for vaccine procurement, distribution, and supportive supervision.

Vaccination service delivery: During the field assessment, including visits to 8 health facilities, it was noted that the MR vaccination service is provided once a week. Still, health workers expressed their willingness to open a 5-dose MR vial even for a single child presenting on any other day. This was also observed in the vaccination session tally sheet entries, which showed sessions when only one child was vaccinated. Both MCV1 and MCV2 administrative coverage have increased by at least 27 percentage points since the switch. Vaccine wastage is not monitored as part of vaccination sessions. Only quarterly reports of wastage are made by comparing the number of doses used and the number of children vaccinated.

Niger

Rationale, national policy and guidelines: Niger transitioned from 10-dose to 5-dose measles vaccine vials with the aim to reduce vaccine wastage and missed opportunities for vaccination. National policy and guideline documents related to the 5-dose switch in Niger were not available for review during the virtual data collection process.

Process of switching to 5-dose vials: The country´s 2018 switch to 5-dose measles vials was supported by expanded cold chain capacity, including the installation of solar-powered equipment through Gavi´s Cold Chain Equipment Optimization Platform (CCEOP). The implementation process was phased, prioritizing the depletion of existing 10-dose stocks before the full rollout of the 5-dose presentation. In preparation for the switch, logisticians at central and regional levels were engaged early to adapt supply chain planning and update national stock management tools, enabling more accurate forecasting and improved wastage tracking. UNICEF provided operational support for cascade training sessions, which emphasized adherence to the open vial policy, best practices for vaccine handling, and strategies to minimize wastage. Communication materials were also developed to explain the change in vial presentation to communities, helping to manage expectations and maintain public trust in the immunization program.

Vaccination service delivery: Health workers reported greater operational flexibility, particularly in rural settings, where the ability to open vials for smaller session sizes enabled more frequent immunization sessions. Preliminary observations suggest that this increase in session frequency may have helped improve coverage, as reflected in administrative data. According to the EPI team, early data also indicated a reduction in wastage rates between 2019 and 2021, which was attributed to the 5-dose switch. The country experienced occasional stockouts due to underestimation of needs, and challenges with continued health worker training and supportive supervision.

Togo

Rationale, national policy and guidelines: The decision to switch to 5-dose MCV vials was driven by the widespread reluctance among health workers to open 10-dose vials outside of scheduled vaccination days. However, when considering the switch to 5-dose vials, Togo did not revise its vaccination policy, but instead, developed written guidance and directives on the launch of 5-dose MCV vials that were sent to the subnational level and to health facilities. The country was supported by partners to calculate the additional costs, and the additional cold chain space required for the switch.

Process of switching to 5-dose vials: Togo implemented the switch to 5-dose MR vials in February 2025 using a staggered approach, with districts transitioning based on their consumption of existing 10-dose vial stocks. Prior to the switch, the Ministry of Health conducted an inventory of 10-dose MR vials and assessed cold chain capacity to determine the appropriate timing for rollout. Districts considered at high risk for measles outbreaks were encouraged to accelerate the use of 10-dose vials through periodic intensification of routine immunization activities. The assessment found that the existing cold chain infrastructure was sufficient to accommodate the 5-dose presentation, thanks in part to previous investments in cold chain expansion and vaccine transport capacity made during the COVID-19 vaccine introduction. In preparation for the transition, the Ministry of Health organized sensitization and training sessions for health workers. Field supervision was carried out shortly after the switch, with funding and technical support from immunization partners.

Vaccination service delivery: As the switch was implemented in 2025, its impact on coverage has yet to be assessed, however, there has reportedly been increased health worker readiness to open vaccine vials with two to three children. In addition, an increased frequency of vaccination sessions was noted, but there was no objective monitoring of session sizes. Other impacts observed by the EPI team include a perceived reduction in MCV wastage rates, and an increase in the number of vaccination sessions. There have been no major operational challenges observed. Health workers have requested for similar shifts to fewer-dose vials for other vaccines like BCG, YF, and Meningitis vaccines.

Zimbabwe

Rationale, national policy and guidelines: The key driver for the switch was the missed opportunities caused by health worker reluctance to open 10-dose vials in a few health facilities, despite national policy allowing vials to be opened for a single child. According to the national immunization program, the vaccine wastage rate was also high while using 10-dose vials. There was no change in the vaccination policy made at the time of the switch. Written communication was sent out and virtual meetings were held with provincial medical directors about the switch, who in turn sensitized their district teams. Zimbabwe reviewed its immunization policy document in 2024, reinforcing the “supermarket approach to health services.” This approach promotes delivering a range of health services in a single location to improve access and utilization of services, thus ensuring that any child presenting to a health facility would benefit on the spot from comprehensive services.

Process of switching to 5-dose vials: After the national EPI program considered the cost implications of the switch and confirmed that there was adequate cold chain space at all levels of the healthcare system, a decision to switch was made. The country rolled out 5-dose MR vials in the third quarter of 2023. Health workers were sensitized to the switch to 5-dose vials during scheduled training for other vaccine introductions, during monthly nurses´ meetings, and integrated supervision visits. The country had previously expanded its cold chain capacity during the introduction of the rotavirus vaccine, which facilitated the accommodation of the 5-dose MR vials. Reportedly, the overall cost of purchasing vaccines did not increase for the country.

Vaccination service delivery: Following the switch to 5-dose vials, vaccinators demonstrated greater willingness to open vials, reflecting improved confidence in using the new presentation. The EPI program has documented a decline in vaccine wastage alongside an approximate 3 percentage point increase in both MCV1 and MCV2 coverage since the switch, according to administrative coverage data. There were no challenges with cold chain space at all levels, except in a few health facilities with a high volume of clients, where the district vaccine stores were available to accommodate the needs through a “consumption-based supply” approach.

Discussion     

The findings presented in this report offer early insight into the operational feasibility and programmatic benefits of transitioning from 10-dose to 5-dose measles/MR vials across diverse country contexts in the WHO African Region. In at least six of the countries reviewed, the primary rationale for the switch was to minimize missed opportunities for vaccination while maintaining acceptable levels of vaccine wastage. Technical immunization partners have provided countries with a simple MS-Excel-based tool and provided technical support to help countries calculate the estimated changes in vaccine volume, cold chain requirements, and costs when switching to fewer-dose presentations [14]. Most countries (six of seven) conducted cold chain and cost analyses in advance, which helped guide decision-making and mitigate logistical risks.

Although data remain limited particularly with respect to standardized monitoring and quantitative post-switch evaluations initial outcomes from all seven countries indicate some improvements: greater flexibility in service delivery, increased frequency of immunization sessions, higher vaccination coverage, reduced vaccine wastage, and strengthened health worker confidence. Administrative data from multiple countries indicated improvements in MCV1 and MCV2 coverage following the switch, with notable gains reported in countries such as DRC and Lesotho. However, with the data quality problems associated with administrative coverage in many countries, it is important to do careful interpretation of coverage trends and to triangulate multiple data sources. In addition to coverage improvements, several countries reported perceived or observed reductions in vaccine wastage, though few had formal monitoring systems in place to quantify these changes reliably. The absence of standardized post-switch assessments and limited documentation of wastage data were common gaps, underscoring the need for improved monitoring tools and independent evaluations. Furthermore, approaches to planning and rollout varied significantly. While four countries followed a structured and coordinated process, others, including Equatorial Guinea, Eswatini, and Lesotho undertook the switch without clear communication, written guidance, or formal training. There was inconsistent involvement of NITAGs, limited development or dissemination of vial-opening policies, and, in many cases, no formal post-switch assessments. The absence of national guidance on vial-opening thresholds critical for health worker training and supervision was a recurring challenge. These gaps point to the need for stronger country-level planning, enhanced partner coordination, and dedicated platforms for cross-country learning and evaluation.

Logistical implications of switching to fewer-dose vials also merit consideration. A commonly effective implementation strategy was to deplete existing 10-dose vial stocks before rolling out 5-dose vials, reducing the potential for confusion or waste during the transition. Additionally, while 5-dose vials generally require more storage space and distribution effort, most countries reported that recent cold chain expansions including those linked to COVID-19 vaccine introduction helped accommodate the change. Nevertheless, as modeling by Tina-Marie Assi et al. has shown, reducing vial size can lead to complex downstream effects on vaccine availability, transportation, and storage across the supply chain [15]. In DRC, for example, switching to 5-dose vials increased the frequency of vaccine deliveries to health facilities, with implications for operational costs. Such changes must be factored into decision-making and budgeting, especially in countries with large birth cohorts or logistical constraints related to transport and storage.

Some modeling studies suggest that the optimal vial size may vary across subnational contexts depending on factors such as session size, supply chain capacity, and coverage goals [16]. WHO AFRO recommends uniform use of 5-dose vials for routine immunization, reserving higher-dose vials for campaigns. This standardization helps streamline logistics, simplifies health worker training and vaccination service delivery.

As additional countries consider the switch to 5-dose vials, the experiences of early adopters offer valuable lessons. One notable gap identified during this review is the absence of a standardized global or regional checklist to guide countries through the switch from 10-dose to 5-dose MCV vials. While some countries may have developed internal planning tools, our study did not systematically assess or document their use. To support more consistent, efficient, and well-coordinated implementation of future dose presentation changes, we strongly recommend the development of a formal global or regional planning checklist or framework. Such a tool would help ensure that all critical preparatory steps ranging from cold chain assessments to health worker training and data tool updates are addressed comprehensively. WHO AFRO and its partners are well-positioned to support countries through technical assistance, coordination platforms, and the dissemination of adaptable implementation tools. Continued documentation, shared learning, and regional collaboration will be essential to strengthen routine immunization systems and to accelerate progress toward measles and rubella elimination targets across the Region.

Limitations: this study has several limitations. Country responses varied in depth across thematic areas, with only a few providing information on key indicators such as vaccine wastage rates. Where such data was available, there were no official or peer-reviewed sources to verify the figures, limiting their reliability and inclusion in this study. In countries where assessments were conducted virtually, national policy and guideline documents related to the 5-dose switch were not reviewed due to limited access to country-level documentation. The number of interviews conducted per country was also limited, and while interviews with EPI managers offered valuable perspectives, these may not fully reflect the broader national or subnational context. Further in-depth, comprehensive assessments involving a wider range of stakeholders at national and local levels, including frontline health workers, are needed to further evaluate the impacts of the transition to 5-dose vials.

Conclusion     

As countries in the WHO African Region work to improve immunization outcomes and close equity gaps, the transition to 5-dose MCV vials presents a timely and practical opportunity to enhance service delivery and reduce missed opportunities. Structured assessments and country experiences suggest that this presentation can lower wastage, increase session frequency, improve access, and build health worker confidence. With deliberate planning, the switch to 5-dose vials can be a key lever for strengthening routine immunization and accelerating progress toward the Region´s 2030 measles and rubella elimination goals. As interest in this approach grows, there is a critical opportunity to move from isolated adoption to coordinated, well-supported implementation. Sustained investment in shared learning, adaptable tools, and structured guidance will be essential to scale impact. The next phase must also prioritize evidence generation and tailored technical support to ensure long-term, measurable gains in measles and rubella control.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

All authors approved the final version of the manuscript.

Acknowledgments     

We would like to sincerely thank the national EPI program managers and team members, as well as the local partners in the various countries, who have contributed to this qualitative study.

References