How Gavi is reaching ‘zero-dose’ children in conflict areas

When the town crier announced that strangers would shortly be arriving in Bopo this March to vaccinate the village children, Shangceline Atia was elated. “This is the first time they are being vaccinated,” she said of her children, aged 7, 5, and 2. With conflict ongoing in southwestern Cameroon and armed insurgents occupying the surrounding forest, the village rarely received visitors, and health workers had been unable to access the area for almost a decade. Atia’s children are among the around 14.5 million globally who have not received their first routine vaccine, DTP1. Known as “zero-dose” children, around 55% live in conflict-affected regions, which are often inaccessible to national immunization programs. The vaccine campaign in Bopo is part of a new initiative from Gavi, the Vaccine Alliance and partners which aims to change that. Known as the Zero-Dose Immunization Programme, or ZIP, the model blends humanitarian and routine immunization practices to reach previously inaccessible areas and address equity gaps in immunization coverage. Humanitarian players such as Médecins Sans Frontières, or MSF, have long included immunization as part of their emergency response to disease outbreaks, conflict, or mass displacement, gaining temporary access to areas where government programs have broken down or cannot access. But ZIP aims to combine that responsiveness with the systems-change approach usually taken by Gavi, focusing on sustainable access to missed communities and full immunization as the main priority. “What we're doing differently here is that we're bringing that full vaccine schedule,” said Amy Ratcliffe, an epidemiologist by training and the acting head of ZIP humanitarian programming at Gavi. The ZIP approach is “very different from the campaign-like strategies that often are what are thought of when we think of humanitarian immunization,” she said. “This is truly new. This is what excites me about ZIP.” Gavi was founded with the goal of boosting equitable and sustainable access to vaccines, procuring vaccines in bulk to guarantee a market for manufacturers and lower prices for countries that otherwise would not be able to afford them. Co-financing by recipient countries is a requirement, with support historically flowing through national governments. That, however, means that areas which are not under government control — such as separatist regions or areas where there is ongoing conflict between the government and nonstate groups — are often excluded from national immunization programs co-financed by Gavi. ZIP was created in 2021 after the Gavi board recognized that one of its core founding principles, its “value of equity, leave no child behind without immunization, was really held back by the channel that our support flows [through],” said Ratcliffe. After selecting implementing partners to award grants to and a short inception phase, immunization began at the end of 2022. In the period from December 2022 through June 2024, ZIP administered 845,000 first doses and 479,000 last doses to infants and children in areas excluded from national immunization programs. Humanitarian access to conflict-affected regions The number of zero-dose children has increased dramatically since the COVID-19 pandemic, while immunization coverage remains lower than in 2019. “We haven't seen the bounce back that we anticipated,” said William Moss, a professor of epidemiology at Johns Hopkins Bloomberg School of Public Health and the executive director of the International Access Vaccine Center, or IVAC. He sees “an opportunity for solutions,” however, in “the fact that in many fragile and conflict affected settings, there are often a number of different humanitarian aid groups working,” he said. Humanitarian organizations operate under the principle of neutrality and are often able to access regions that national programs cannot. This enables them to provide health services in communities facing conflict or displacement, or negotiate pauses in conflict to respond to disease outbreaks. In Gaza, for example, UNICEF and the World Health Organization led negotiations for a humanitarian pause after the region’s first polio case in 25 years, allowing organizations such as MSF to conduct vaccination campaigns. But while humanitarian campaigns may have access to conflict-affected areas that others do not, they often face structural barriers to vaccination. MSF has faced restrictions on importing vaccines and delays in permission to use national supplies. An MSF vaccination campaign in response to a measles outbreak in South Sudan last year, for example, was delayed by four months because of bureaucratic and vaccine supply hurdles. Negotiations to access vaccines can often take months or even years, said Victorine de Milliano, advocacy adviser at MSF. “But if there's an outbreak, you don't have months, and you definitely don't have a year,” she said. Reaching children in conflict-affected settings is often also more expensive, she acknowledged. But “making sure that we reach these populations, even though you might reach a bit less for the same amount of money,” is an important investment because “otherwise we will just see outbreaks happening over and over again,” she said. Focusing on equity rather than overall coverage makes sense from an epidemiological perspective, agreed Moss. “It's not necessary to reach every zero-dose child” to prevent outbreaks, he said. “What you want to do is ensure that there's enough population immunity by identifying and reaching missed communities.” Blending a humanitarian and immunization approach ZIP aims to combine these humanitarian approaches with Gavi’s ability to program “with an oversight function, due diligence and all of the accountability that’s needed,” said Ratcliffe. While the vaccines almost always still come from the national government’s supply, implementation is instead overseen by local humanitarian partners such as the International Rescue Committee, or IRC, facilitating access to areas previously off limits. In countries where IRC runs ZIP campaigns, such as Ethiopia and South Sudan, access has increased from 16% of the districts to 96%. The focus on both equity and sustainability is an acknowledgement that for many zero-dose children, such as Atia’s children in Cameroon, crisis is a chronic condition. In the southwestern region where her village is located, health workers are unable to reach communities because of the risk of kidnapping, said Atia. “People are afraid to come here, because when they come, [the armed groups] will hold them hostage,” she said. Cameroon’s “Anglophone crisis,” a conflict between armed Anglophone separatist groups and the Francophone-majority government, has been ongoing since 2016. It has left over 900,000 people internally displaced, and an estimated 350,000 children unvaccinated or undervaccinated. “Most of the health facilities were burned, and the routine health system is not able to effectively deliver vaccination services because government health workers are not accepted,” said Eugène Foyeth, a vaccination program manager at the nonprofit Cameroon Baptist Convention Health Services, or CBCHS — a Gavi implementing partner in the region. In areas where local armed groups are in conflict with the national government, there is often “a lot of distrust that has been built over time, and that is making people despise government services,” said Delphine Fri, gender equality and social inclusion lead at CBCHS. The faith-based organization, which led the vaccination drive in Bopo, was able to access the community because it is seen as a neutral party by both the nonstate armed group and the government. Neutrality is a core humanitarian principle that is new to Gavi. Its integration into the blended ZIP approach “is really what allows the ZIP partners to navigate with stakeholders, especially when they're engaged in conflict,” said Ratcliffe. A mistrust of government services, often perpetuated by separatist propaganda, can stifle demand for vaccines as well as access. Mothers often tell the CBCHS team that “it is difficult for us to trust the same people that are killing us,” said Fri. CBCHS often uses its network of pastors and community health workers to build trust within the community. Before working in a new area, the team “start by mapping all the stakeholders that are there,” said Fri. “Who is influencing decisions in these communities, be it the community leaders, be it the religious leaders.” They then work with these community leaders to co-create messages, said Foyeth, building demand. In Bopo, the vaccination team coordinated with the local community health worker — a person whom Atia said the community “trusts very much,” because he helps them when their children are sick. If the vaccination team had arrived unannounced, “we would have refused, because there are rumors that some of these vaccines are dangerous to our health,” she added. As well as concerns about the vaccine and mistrust of government health workers, community members also fear that cooperating with outsiders may result in them being labeled a “black leg” — a pejorative term for people who collaborate with the oppressor. “People may like or want what you're bringing, but because the people governing that place have not approved it, they will not go for it,” said Fri. Data gaps hide coverage gaps While access to zero-dose children can be difficult, often, the biggest hurdle is finding them in the first place. “Quantifying the problem can be very challenging,” said IVAC’s Moss. Displacement means that population estimates are often inaccurate, and many countries lack comprehensive demographic survey data. Where data is available, it tends to be clustered in more accessible areas, he added. “So you just don't have any coverage data that's representative in that way.” Studies conducted by IVAC have attempted to use geospatial modeling to quantify immunization coverage gaps. The most recent study mapping survey data in conflict settings was discontinued midway after U.S. funding cuts, said Moss. Similarly, modeling by the WHO/UNICEF estimates of national immunization coverage relies partially on data from Demographic and Health Surveys, a program which has been suspended as part of the freeze on U.S. foreign aid. While modeling can help to direct ZIP toward immunization coverage gaps, however, accurately quantifying them is more difficult — particularly in areas with high levels of displacement. But up-to-date numbers are important in ensuring steady vaccine supply and the correct allocation of resources. “The numbers really matter to us,” said Ratcliffe. To help quantify need, ZIP also incorporates humanitarian data sources from its local partner organizations such as CBCHS. The CBCHS team “visit the records of the community, and we also visit the traditional birth attendant,” said Foyeth. Once they have pinpointed the location of the zero-dose children, he said, they send vaccinators door to door, updating records as they go. Often, the government “uses our actual data to update their population baseline,” he said. Quantifying need and tracking actual doses administered is also important for accountability, “to ensure the return on investment for Gavi on a set of awards that were really so new and so innovative,” said Ratcliffe. “We needed to really demonstrate that we were reaching children and moving them along the full vaccine schedule.” Gavi has set targets this year using the latest estimates of need from grantees, with the goal of meeting 70% of that need, said Ratcliffe. But while she is optimistic that they are on track to reach those targets, she cautioned that a dynamic security environment requires flexibility and constant monitoring. Whereas normally “you'd be able to make an investment, set targets, and you would just expect your grantees to meet those targets,” she said, Gavi often needs to work with grantees to navigate emerging risks or structural barriers. “We’re more engaged than a typical donor might be,” she said. An evolving model While it was initially thought that Gavi partners could negotiate access and then revert to a standard routine immunization approach, it quickly became apparent that flexibility in the ways that partners operate locally is important too. In Cameroon, the approach needs to be “tailored” based on the “granular community characteristics, to ensure that we effectively reach every child where they are,” said CBCHS’ Foyeth. In some places, the team needs to embed for several days to build trust and educate the community on the importance of vaccines, whereas in others, they need to conduct quiet, door-to-door vaccine drives as quickly as possible so as not to attract attention, he said. Those approaches need to be constantly reviewed as local insurgencies gain and lose control of areas, and access has to be renegotiated. “We may have access now, and then at some point, we do not have access again in that same community,” said CBCHS’ Fri. CBCHS relies on building relationships with local community leaders who can give them up-to-date information on emerging security situations. “We connect with them to ask if the roads are clear, they give us a green light before we go,” said Fri. Ensuring sustained access is about building resilience, said Ratcliffe, and can sometimes even necessitate handing over operational control to another partner entirely. “We really want to develop programming that can respond and meet the needs of communities, no matter who does it, and finding that right partner is critical,” she said. The model is still evolving, said Ratcliffe, with an increasing focus on prioritizing local partners who “can respond faster in times of crisis to meet the needs of communities that are either newly missed or at risk of losing immunization services.” The balance of oversight and adaptivity is still something that Gavi is working to get right, she said. Other problems remain unresolved. Under the “Big Catch-Up,” a global immunization initiative to catch up with children who missed vaccines during the COVID-19 pandemic, routine immunization for children up to the age of 5 is co-financed by Gavi and partners. But older children are not covered, even in areas that have been cut off because of conflict for years at a time. Of Atia’s three children in Bopo village, only the youngest two were able to receive doses. And when the Big Catch-Up ends later this year, the age limit will revert to 2 years old. But “there's more than just the infant cohorts that have missed their basic childhood vaccines,” said MSF’s de Milliano, calling for Gavi to ensure that funding remains in place to support older children too. But funding for Gavi as a whole is increasingly at risk. Earlier this year, it delayed its replenishment summit until June, faced with a precarious funding environment. With donors such as the U.S. and the U.K. expected to terminate or significantly reduce their support, meeting the targeted $9 billion looks increasingly uncertain. If funding falls short, ZIP’s future remains unclear. But advocates of the program hope that the lessons learned will have a long-term impact on immunization practices and vaccine equity regardless, offering a blueprint for how to reach those excluded from national systems. “I've never seen a project create feedback loops and get change at an institutional, global level as quickly as ZIP has,” said Ratcliffe. “This is the coolest project I've worked on in my entire career.”