Catherine R. McGowan

Background: A large and increasing number of people are forcibly displaced worldwide because of war, food insecurity, and other crises. Streptococcus pneumoniae likely causes a substantial health burden in crisis-affected populations. Pneumococcal conjugate vaccines (PCVs) are widely used in routine immunisation programmes, including through the Essential Programme on Immunization (EPI) to protect against pneumococcal disease. They are typically administered as a three-dose schedule, either as three doses in early infancy or two doses in infancy followed by a booster at 9–18 months of age. However, PCVs are rarely used in humanitarian responses. We evaluated the potential impact of logistically feasible PCV campaigns in such settings. Methods and findings: We conducted a pneumococcal carriage, malnutrition, and social contact survey in a camp for displaced people near Hargeisa, Somaliland, to parameterise a transmission model accounting for migration. We projected the effect of PCV mass-vaccination campaigns using one or two doses and vaccinating children <1, 2, 5, 10, or 15 years (y) of age in the Somaliland camp and three different crisis settings. We found that a single-dose PCV campaign with high vaccine coverage in children <5 y or older can partially control vaccine-serotypes for up to 3 y, preventing 27% (95% CrI: 20, 34) of severe pneumococcal disease, defined as a composite of invasive pneumococcal disease and nonbacteraemic pneumonia, when vaccinating <5 y olds and 38% (95% CrI: 29, 46) when vaccinating <15 y olds. Expanded age eligibility is needed for comparable protection in settings with increased migration or more interaction with unvaccinated host populations. A campaign vaccinating <5 y olds is the most efficient use of PCV with 108 (95% CrI 77–162) vaccines needed to prevent one case of severe pneumococcal disease. Implementing such campaigns in displaced populations worldwide would require about 30 million doses in the next 5 y. Key limitations included sparse empirical data on PCV effectiveness and pneumococcal disease in humanitarian settings, and extrapolation of Somaliland carriage and contact patterns to other crisis settings. Conclusions: Single-dose mass-vaccination campaigns offer crisis-affected populations an effective, pragmatic immunisation strategy to deliver PCVs if routine EPI services have been disrupted.

Introduction: Mortality patterns in humanitarian crises are shaped by intersecting factors including violence, displacement, health system disruption and environmental shocks. While crude and under-five mortality rates are often tracked, less is known about specific causes of death across diverse crisis contexts. Existing guidance informing humanitarian response is largely informed by outdated evidence and does not account for demographic, epidemiological and geopolitical shifts over the past two decades. This review aims to synthesise available data on cause-specific mortality in humanitarian settings to inform improved monitoring, policy and response. Methods and analysis: We will conduct a scoping review of peer-reviewed and grey literature reporting on causes of death in humanitarian crises between 2015 and 2025. Eligible studies will include crisis-affected populations in locations with an active Humanitarian Response Plan during analysis. We will search Medline, Embase and Global Health, and screen organisational datasets from key humanitarian agencies. A large language model will be used to assist with title and abstract screening. Full-text screening and data extraction will be conducted manually by two reviewers. Methodological quality will be assessed using study-type-specific appraisal tools. Data will be extracted using a standardised plan and synthesised narratively. Ethics and dissemination: Ethics approval is not required as this study uses publicly available data. Findings will be submitted to a peer-reviewed journal and disseminated via policy briefs, academic presentations and targeted stakeholder engagement.

Background: Recent evidence suggests that just over a third of children aged 12–23 months in Nigeria have received basic antigens as recommended by the expanded programme on immunisation schedule; just over a quarter have received all first year antigens. Approximately 18% of children in Nigeria are classified as ‘zero-dose’. We assessed the status of immunisation services in Kano and Lagos States of Nigeria to inform the design of interventions to address high numbers of zero-dose and under-immunised children in these states. Methods: We used a mixed-methods study design. We collected information from caregivers (including female and male caregivers; and caregivers of zero-dose, under-immunised, and immunised children), and healthcare workers. We conducted focus groups and key informant interviews amongst caregivers of zero-dose and non-zero-dose children. We interviewed caregivers and observed vaccination sessions. We carried out facility observation of vaccination sessions. Data collection tools were adapted from the WHO expanded programme on immunisation review guidelines. Results: Whilst we identified many positive practices - and exit interviews suggested high satisfaction with vaccination services - we identified important areas for improving services. Specific challenges related to the: 1) staff (including insufficient staff to operate vaccination activities, poor information exchange with caregivers, low planning capacity, sub-optimal health and safety practices, and abrasive healthcare worker attitudes); 2) facility (including unwelcoming and uncomfortable facility environments and occasional vaccine shortages), and 3) programme design/delivery (including poor planning/service integration, and insufficient resources for transportation/outreach services). Conclusion: We suspect that many of the identified challenges are interrelated (e.g. insufficient staff numbers, and an uncomfortable facility environment, may contribute to poor interaction between healthcare workers and caregivers) and that addressing some of these challenges may have cascading effect on vaccination coverage. A better understanding of improving service design and delivery to incentivise visits to vaccination services is needed.

Ethiopia has the fourth-highest number of zero-dose children globally. Negative experiences and perceptions of immunization are recognized barriers to vaccination uptake but warrant context-specific investigation. We explored barriers and enablers to immunization uptake in selected regions of Ethiopia. We conducted a formative qualitative study involving 18 focus group discussions with men and women, in-depth interviews with 23 mothers of children with varying immunization statuses, and 42 key informant interviews with religious and community leaders and health workers in eight districts in Amhara, Oromia, and Somali regions. We identified shared and regionally distinct barriers. Common barriers included limited access to services in hard-to-reach areas, low awareness of immunization, competing household responsibilities for mothers, fear of side effects, and a lack of compassionate and respectful care from health workers. Forgetting vaccination appointments was frequently reported in Amhara and Oromia. In Amhara and Somali, mistrust of vaccinators and infrequent vaccination sessions were salient challenges. In Amhara, some believed that envy or praise by vaccinators could bring harm or misfortune to children, and that vaccination should be delayed until after baptism. In Oromia, beliefs that vaccines aggravate illness and that infants should not leave home before six months of age were reported. In Somali, perceived parental negligence and beliefs that vaccines are unnecessary were described. Engaging community, traditional, and religious leaders and fathers in immunization activities in Oromia, and aligning vaccination sessions with local holidays in Amhara, emerged as promising practices. Our findings show that knowledge and perceptions of vaccines, cultural norms, service accessibility, and experiences with vaccine-preventable diseases (VPDs) and vaccination can either encourage or discourage uptake. We recommend enhancing service delivery, improving caregiver interactions, and implementing two-way community engagement involving religious and community leaders, and caregivers of fully vaccinated children, with a focus on highlighting reductions in VPD burden.

Globally, an estimated 22.7 million children are unimmunized or ‘zero-dose’ (ZD), with 3.1 million in Nigeria. The political and economic environment plays a critical role in influencing the number of ZD and under-immunized children. We explored stakeholder perceptions of the political and economic context of vaccination services in Kano and Lagos States, two Nigerian States with a high number of ZD children. We conducted stakeholder mapping, followed by key informant interviews with 84 State, local, and community informants responsible for or influential in immunization. Transcripts were analyzed using a reflective thematic framework approach. We describe the multi-level network of domestic and international actors characterizing Nigeria's immunization policymaking and implementation landscape. Respondents perceived a strong and mutual political commitment by all actors involved in routine immunization. The pivotal role of local influencers further reinforced this commitment, from traditional to religious leaders, to improving uptake in challenging settings. Knowledge of national policies, and thus, perception of their adequacy in addressing under-immunization, was weakest among participants working at the local and community levels. Other reported barriers to policy implementation included bureaucratic delays in fund disbursement, outdated policies, slow dissemination of policies to local levels, and inadequate policy provisions for funding and staffing at the local level. To enhance equitable immunization coverage in Kano and Lagos, our findings suggest a need for meaningful engagement of community actors in policy development, timely policy revisions, and the establishment of mechanisms for expediting fund disbursements and addressing funding shortfalls at the local levels.

Armed conflict causes pervasive harm to children, and humanitarian responses to support them face significant challenges. This review aims to summarise the evidence on the effectiveness of interventions to treat, protect, and promote child public health in conflict-affected populations. A systematic review was performed, with searches of major databases and the grey literature from 1 January 2012 – 20 February 2025. Included studies provided data on child or caregiver outcomes associated with interventions to support children affected by armed conflict. Studies on nutrition and perinatal interventions were excluded. Data were extracted on the setting, population, intervention design, study type, and findings. The searches yielded 3,601 records. 51 intervention studies met inclusion criteria, 39% of which were trials. Studies were mainly from Africa (51%), the Middle East (25%) and Asia (18%). The majority of studies focused on mental health and psychosocial support (MHPSS) (N = 29, 57%). MHPSS, child protection, and/or parenting interventions were the focus of trials as well as intersectoral interventions. Somatic child health interventions (N = 19, 37%) focused on immunisation, adolescent sexual and reproductive health, toxic stress, and telemedicine services. Five studies measured development outcomes and one intervention targeted children with disabilities. Over half of the studies were carried out amongst displaced populations. Intervention design varied widely within and between sectors. Studies showed promising results, particularly for non-specialist MHPSS interventions. Only 20% of studies assessed intervention safety. The evidence for child public health interventions to support conflict-affected populations is increasing, with increased numbers of studies over time, and improved study design, execution, and reporting. However, the evidence remains poor, limited to a few topic areas and with continued geographical disparities. There are notable gaps in evidence on the safety of interventions, their medium- and long-term impacts, sustainability, and interventions for child development and children living with disabilities.

Background: Armed conflict causes pervasive harm to children, and humanitarian responses to support them face significant challenges. This review aims to summarise the evidence on the effectiveness of interventions to treat, protect, and promote child public health in conflict-affected populations. Methods: A systematic review was performed, with searches of major databases and the grey literature from 1 January 2012 – 20 February 2025. Included studies provided data on child or caregiver outcomes associated with interventions to support children affected by armed conflict. Studies on nutrition and perinatal interventions were excluded. Data were extracted on the setting, population, intervention design, study type, and findings. Results: The searches yielded 3,601 records. 51 intervention studies met inclusion criteria, 39% of which were trials. Studies were mainly from Africa (51%), the Middle East (25%) and Asia (18%). The majority of studies focused on mental health and psychosocial support (MHPSS) (N=29, 57%). MHPSS, child protection, and/or parenting interventions were the focus of trials as well as intersectoral interventions. Somatic child health interventions (N=19, 37%) focused on immunisation, adolescent sexual and reproductive health, toxic stress, and telemedicine services. Five studies measured development outcomes and one intervention targeted children with disabilities. Over half of the studies were carried out amongst displaced populations. Intervention design varied widely within and between sectors. Studies showed promising results, particularly for non-specialist MHPSS interventions. Only 20% of studies assessed intervention safety. Conclusion: The evidence for child public health interventions to support conflict-affected populations is increasing, with increased numbers of studies over time, and improved study design, execution, and reporting. However, the evidence remains poor, limited to a few topic areas and with continued geographical disparities. There is a lack of studies from Central and South America, the Caribbean, North Africa, West Africa, Southeast Asia, and the Pacific. There are notable gaps in evidence on the safety of interventions, their medium- and long-term impacts, sustainability, and interventions for child development and children living with disabilities.

Summary: Background: A large and increasing number of people are forcibly displaced worldwide because of war, food insecurity, and other crises. Streptococcus pneumoniae (the pneumococcus) likely causes a substantial health burden in crisis-affected populations, but pneumococcal vaccines (PCVs) are rarely used in humanitarian responses. We evaluated the potential impact of logistically feasible PCV campaigns in such settings. Methods: We conducted a pneumococcal carriage, malnutrition and social contact survey in a camp for displaced people near Hargeisa, Somaliland, to parameterise a transmission model accounting for migration. We projected the effect of PCV mass-vaccination campaigns using one or two doses and vaccinating children <1, 2, 5, 10 or 15 years (y) of age in the Somaliland camp and three different crisis settings. Findings: A single-dose PCV campaign with high vaccine coverage in children <5y or older can partially control vaccine-serotypes for up to three years, preventing 27% (95%CrI 20-34) of severe pneumococcal disease when vaccinating <5y olds and 38% (95%CrI 29-46) when vaccinating <15y olds. Expanded age eligibility is needed for comparable protection in settings with increased migration or more interaction with unvaccinated host populations. A campaign vaccinating <5y olds is the most efficient use of PCV with 108 (95%CrI 77-162) vaccines needed to prevent one case of severe pneumococcal disease. Implementing such campaigns in displaced populations worldwide would require about 40 million doses in the next five years. Interpretation: Single-dose PCV mass-vaccination campaigns offer crisis-affected populations an effective, pragmatic immunisation strategy. Funding: This study was funded by Elrha’s Research for Health in Humanitarian Crises (R2HC) Programme. Research in context: Evidence before this study: Acute respiratory infections are a leading cause of morbidity and mortality in crisis-affected populations, but pneumococcal conjugate vaccines are rarely used in humanitarian responses. Routine vaccination is often not feasible in these settings due to a lack of access or security, and there is little guidance on alternative delivery options for these vaccines. A literature search on Apr 10, 2025, using the terms (“pneumococcal conjugate vaccine*” OR “PCV”) AND (“humanitarian” AND (“cris*” OR “emergenc*”)) returned 9 results on Embase and 8 results on PubMed. PCV mass vaccination strategies have previously been shown to be cost-effective in crisis settings, but no study has directly compared the effect and efficiency of different age eligibility and dosing regimens in crisis-affected populations. Added value of this study: We collected key primary data that would allow us to parameterise a model to project the effect of different PCV campaigns on the transmission of vaccine-type pneumococci. To our knowledge, this is the first analysis that has assessed the combined direct and indirect effect of PCV campaigns in crisis-settings. We show the importance of achieving high levels of indirect protection for a substantial and sustained impact, which can be realized by vaccinating the main transmitters in addition to the children at highest risk of severe disease. We show that this can likely be achieved using a single-dose strategy, which greatly improves the feasibility of a campaign. Implications of all the available evidence.: Single-dose mass-vaccination PCV campaigns that achieve high coverage in children up to 14 years (y) of age can provide substantial health benefits in crisis-affected populations. Vaccinating <5y olds may be most efficient. Temporarily disrupting transmission of vaccine-type pneumococci is crucial to protect unvaccinated children born or in-migrated after the campaign.

Background: The war in Tigray Region, Ethiopia (November 2020 to November 2022) ended with formal commitments to accountability, but these have yet to produce publicly available accounts of the harms caused by the conflict. Methods: We carried out an online survey of the Tigrayan diaspora to estimate mortality amongst children, adults, and older adults during, and prior to, the war-period. We collected retrospective demographic information on respondents’, and their spouses’, extended family inside Tigray. To mitigate selection bias, we standardised mortality estimates by rural-urban residence and wealth index. Results: Of 1011 participant-reported decedents, 810 died within Tigray, and 310 of these individuals died during the war-period. Of the 310 deaths in Tigray during the war-period, 224 (72.3%) died from intentional injuries. The standardised mortality rate for adults (15–49 years) was 21.3 per 1000 person-years (29.4 for men, 14.8 for women) during the war, and 1.0 in the preceding period (2010–2020). The mortality rate amongst older adults (≥ 60 years) was 45.1 per 1000 person-years during the war-period, compared to 22.8 in 2010–2020, and is higher than the period encompassing the Ethiopian Civil War (1974–1991) and Tigray/Wollo Famine (1984–1985). The mortality ratio (men to women) was approximately 2:1 in both adults, and older adults. The mortality rate amongst adults and older adults had been declining across the pre-war periods. Few deaths were reported amongst children. We estimate that the conflict has resulted in more than 102,000 deaths amongst those aged ≥ 15 years. Conclusions: Our study suggests a significant elevation in all-cause mortality, largely driven by intentional injuries. Although our pre-war-period data are likely under-reported, comparisons with other pre-war estimates corroborate these plausible elevations, particularly amongst adults. The mortality ratio, when compared to those from other settings, does not support assertions that the military strategy primarily involved the targeting of adult males, and instead suggests widespread killing of women and older adults who would not have posed a combat threat.