Vaccine[JOURNAL]
Sun
200 papers
Systematic review and meta-analysis of digital seasonal influenza vaccination promotion in people aged ≥50 years.
Chen S, Fang Y, Yu FY … +3 more , Ding L, Mo PKH, Wang Z
Vaccine · 2026 Jun · PMID 42320382 · Publisher ↗
BACKGROUND: Digital educational interventions may provide scalable approaches to promote seasonal influenza vaccination (SIV). However, their effectiveness among adults aged ≥50 years remains uncertain. METHODS: We cond...
BACKGROUND: Digital educational interventions may provide scalable approaches to promote seasonal influenza vaccination (SIV). However, their effectiveness among adults aged ≥50 years remains uncertain. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials evaluating digital educational interventions to increase SIV uptake in adults aged ≥50 years. Nine databases (PubMed, MEDLINE, Embase, Web of Science, Global Health, CINAHL, Cochrane Library, APA PsycINFO, and APA PsycArticles) were searched from inception to January 20, 2026, without restrictions on country or setting. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were estimated using random-effects models. This review was registered in PROSPERO (CRD420261289379). RESULTS: Of 4365 records identified, 11 trials met the inclusion criteria, of which 10 were included in the meta-analysis. Digital educational interventions were associated with a significant increase in vaccination uptake (pooled RR = 1.21, 95% CI: 1.07-1.37; p = 0.002). Significant intervention effects were observed among adults aged 50-64 years (pooled RR = 1.02, 95% CI: 1.01-1.04; p = 0.004) and those aged 65 years or above (pooled RR = 1.15, 95% CI: 1.03-1.28; p = 0.01). Multi-session interventions and interventions combining educational information with vaccination reminders significantly improved uptake, whereas one-off interventions and education-only interventions showed no significant effects. Both manually delivered and fully automated interventions were associated with improved uptake, with no significant difference by delivery mode. CONCLUSIONS: Digital educational interventions were associated with increased SIV uptake among middle-aged and older adults. These approaches may complement existing population-level vaccination programs.
Cross-sectional analysis of chikungunya vaccine acceptability among residents of Ponce, Puerto Rico, 2024-2025.
Guagliardo SAJ, Major CG, Rodriguez DM … +4 more , Rivera-Amill V, Staples JE, Adams LE, Hills SL
Vaccine · 2026 Jun · PMID 42320381 · Publisher ↗
Chikungunya virus has previously caused outbreaks in U.S. territories. Recent chikungunya vaccine availability has expanded prevention options. We conducted a cross-sectional analysis of the acceptability of a hypothetic...
Chikungunya virus has previously caused outbreaks in U.S. territories. Recent chikungunya vaccine availability has expanded prevention options. We conducted a cross-sectional analysis of the acceptability of a hypothetical chikungunya vaccine provided at low or no cost among residents of Ponce, Puerto Rico. Among 2437 survey participants, 70.7% indicated they would get the vaccine, 22.6% would not, and 6.7% were unsure. Multivariable logistic regression showed that, after accounting for sex, vaccine acceptance was lower for participants aged 31-50 years (adjusted Odds Ratio [aOR]: 0.51, 95% confidence interval [CI]: 0.37-0.69) and > 50 years (aOR: 0.67, 95% CI: 0.47-0.95) compared with younger adults, and for people completing some higher education (aOR: 0.45, 95% CI: 0.26-0.78) compared with those with less than high school education. The most common reason for being uninterested or unsure was wanting to know about vaccine safety and side effects, emphasizing the importance of education and communication efforts to improve vaccine uptake.
Timing and frequency of antenatal care visits in relation to maternal respiratory syncytial virus vaccine opportunities in four Latin American countries.
Fleming JA, Colistro V, Knudson S … +1 more , Colomar M
Vaccine · 2026 Jun · PMID 42320380 · Publisher ↗
INTRODUCTION: The Latin American and Caribbean region (LAC) has historically been an early adopter of new vaccines, including the recently introduced maternal vaccine to protect infants against respiratory syncytial viru...
INTRODUCTION: The Latin American and Caribbean region (LAC) has historically been an early adopter of new vaccines, including the recently introduced maternal vaccine to protect infants against respiratory syncytial virus (RSV). Since maternal RSV vaccination requires gestational age (GA)-specific administration, antenatal care (ANC)-based delivery feasibility depends on ANC visit timing and frequency. We assessed ANC attendance relative to recommended vaccination windows in four LAC countries to inform planning for maternal RSV vaccine implementation and future maternal immunization programs. METHODS: We conducted a retrospective, cross-sectional analysis from Perinatal Information System data across eight tertiary facilities in Bolivia, Ecuador, Honduras, and Uruguay. Women 15-45 years old with ≥1 ANC visit in 2023 and a live, singleton birth at a study facility were included. GA per visit was extracted or derived from last menstrual period or birth data. We defined RSV vaccination eligibility according to Pan American Health Organization (PAHO) (32-36 weeks) and World Health Organization (WHO) (≥ 28 weeks) recommendations. Descriptive analyses summarized ANC initiation, visit timing, and the proportion of women attending visits within eligibility windows. RESULTS: We included 37,604 women. The median GA at ANC initiation was 12 weeks, ranging from 10 weeks (Uruguay) to 15 weeks (Ecuador). Overall, 63.5% of women attended at least one ANC visit during the PAHO window, with country-specific proportions from 53.6% (Honduras) to 82.3% (Uruguay). Attendance within the WHO window was higher (91.4%). Median ANC attendance was five visits, ranging from five (Honduras) to eight (Uruguay). Earlier ANC initiation was associated with higher visit counts. DISCUSSION: There is substantial potential for achieving high maternal RSV vaccine coverage in LAC, particularly per broader WHO vaccine recommendations. Where ANC begins later or visits are fewer, narrower vaccine-eligible windows may limit achievable coverage. Strengthening early ANC engagement and immunization counseling may increase vaccination opportunities.
Longitudinal evidence of differential pertussis antibody durability following natural infection among vaccinated children living in contrasting malaria transmission settings in coastal Kenya.
Safari MS, Gicheru ET, Mburu MW … +9 more , Makori TO, Nyawa O, Odoyo SO, Shee F, Ndungu F, Foley DJ, Nyagwange J, Chege T, Sande CJ
Vaccine · 2026 Jun · PMID 42314312 · Publisher ↗
BACKGROUND: Despite widespread pertussis vaccination, re-surgent infections have been reported globally, driven partly by waning immunity after primary vaccination. While antibody decay patterns following vaccination are...
BACKGROUND: Despite widespread pertussis vaccination, re-surgent infections have been reported globally, driven partly by waning immunity after primary vaccination. While antibody decay patterns following vaccination are well described, little is known about the influence of malaria endemicity on the maintenance of pertussis-specific antibodies. METHODS: We analysed longitudinal serum samples from 92 children from two neighbouring communities on the Kenyan Coast with contrasting malaria transmission intensities: Junju (high transmission, n = 44) and Ngerenya (low transmission, n = 48). Participants were followed from childhood for up to 14 years, with annual serum sampling and continuous active malaria surveillance. Vaccination histories were verified through immunisation records. Pertussis toxin (PT) -specific IgG was quantified using an in-house protein microarray platform, and antibody dynamics were compared by vaccination status and background malaria exposure. RESULTS: Vaccinated children exhibited patterns of gradual post-vaccination antibody decay, with titres stabilising at low levels by approximately 10 years of age. Among vaccinated children who later experienced natural infection, anti-PT titres rose sharply before diverging by malaria transmission setting. In Ngerenya, antibody levels remained stably elevated for several years post-infection, whereas in Junju, antibodies decayed rapidly, returning to pre-boost levels within a few years. CONCLUSION: Chronic malaria exposure in early life, may be associated with accelerated waning of infection-induced pertussis antibodies. These findings may suggest that persistent malaria transmission may erode long-term humoral immunity, with implications for pertussis control and booster scheduling in endemic regions.
In silico comparison of the differential proteome produced by the tuberculosis vaccine candidate BCGΔBCG1419c and its parental BCG strain cultured as biofilms or planktonic cells.
Flores-Valdez MA, Velázquez-Fernández JB, Vallejo-Cardona AA … +2 more , Aceves-Sánchez MJ, Rodríguez-Campos J
Vaccine · 2026 Jun · PMID 42314311 · Publisher ↗
Bacillus Calmette-Guérin (BCG) is employed to prevent tuberculosis (TB) during childhood. We reported the proteome of our vaccine candidate BCGΔBCG1419c and its parental BCG Pasteur ATCC 35734 strains, when cultured eith...
Bacillus Calmette-Guérin (BCG) is employed to prevent tuberculosis (TB) during childhood. We reported the proteome of our vaccine candidate BCGΔBCG1419c and its parental BCG Pasteur ATCC 35734 strains, when cultured either as mature biofilms in Sauton medium or as planktonic cells in 7H9 OADC Tween 80 medium. Here, we perform in silico analyses aiming to determine: (1) proteins differentially produced in biofilm compared with planktonic cultures, either in BCGΔBCG1419c or its parental strain, and (2) proteins differentially produced in BCGΔBCG1419c compared with its parental regardless of growth condition, namely mature biofilms in Sauton medium or as planktonic cells in 7H9 OADC Tween 80 medium. Proteomes produced were affected not only by the mutation of the BCG1419c gene, but also by growth condition (planktonic or biofilm). Then, changes deteced might reflect a combined culture system difference encompassing growth architecture, nutrient formulation, detergent presence, and growth physiology, which impact proteome and possibly immune-relevant responses.
Willingness to pay for influenza vaccination among the elderly in Vietnam: A triple-bounded dichotomous choice analysis of economic and behavioral determinants.
Le MH, Tran ND, Nguyen TTT … +3 more , Phan TTN, Pham TT, Tran ND
Vaccine · 2026 Jun · PMID 42314310 · Publisher ↗
BACKGROUND: Seasonal influenza causes significant morbidity among the elderly, yet vaccination remains an out-of-pocket expense in Vietnam. This study evaluated the willingness to pay (WTP) for influenza vaccination and...
BACKGROUND: Seasonal influenza causes significant morbidity among the elderly, yet vaccination remains an out-of-pocket expense in Vietnam. This study evaluated the willingness to pay (WTP) for influenza vaccination and its determinants among the elderly in Vietnam. METHODS: A community-based cross-sectional study was conducted in Can Tho City, Vietnam (N = 1486). We employed the Contingent Valuation Method with a Triple-Bounded Dichotomous Choice framework. Data were analyzed using multivariable logistic regression to identify predictors of WTP and interval regression to estimate the mean WTP and its monetary determinants. RESULTS: Overall, 54.9% of participants expressed a WTP, but only 28.9% were willing to cover the full market cost. The estimated mean WTP was 12.08 USD (95% CI: 11.66-12.50). Logistic regression revealed that vaccine hesitancy was the strongest predictor; non-hesitant individuals were 13.71 times more likely to express WTP (p < 0.001). Other significant predictors included high income (aOR = 2.22), medical recommendations (aOR = 1.80),and diabetes mellitus (aOR = 1.41). Interval regression showed that vaccine hesitancy "devalued" the vaccine by approximately 30%, with highly hesitant individuals willing to pay 4.12 USD less than those with low hesitancy. Conversely, media exposure increased the WTP amount by 1.10 USD. Most respondents (66.1%) identified the state budget as the preferred financial support source. CONCLUSIONS: A significant affordability gap exists for influenza vaccination among the Vietnamese elderly. While financial subsidies are necessary to support low-income groups, they must be paired with communication strategies to reduce vaccine hesitancy. We recommend a subsidized co-payment model (minimum 4-5 USD subsidy per dose) and leveraging healthcare provider recommendations to enhance vaccine valuation and uptake.
Recombinant subunit vaccines against invasive fungal infections: mechanisms, development progress, and therapeutic potential.
Xu X, Jiang B, Xiong J … +2 more , Jiang Y, Lu H
Vaccine · 2026 Jun · PMID 42314309 · Publisher ↗
Invasive fungal infections are an escalating global public health threat, especially among immunocompromised populations, with high morbidity and mortality. Traditional antifungal drugs are limited by reduced efficacy, i...
Invasive fungal infections are an escalating global public health threat, especially among immunocompromised populations, with high morbidity and mortality. Traditional antifungal drugs are limited by reduced efficacy, inherent toxicity, and rising drug resistance, creating an urgent need for innovative therapeutic strategies. Recombinant subunit vaccines, as safe, specific, and scalable immunotherapeutics, hold great promise for addressing this unmet medical need. This review systematically summarizes the research advancements of recombinant subunit vaccines against invasive fungal infections. It first elaborates on the immunological mechanisms of fungal infections (innate and adaptive immunity) and the action mechanisms of recombinant subunit vaccines (specific and non-specific immune responses). Then, it categorizes and analyzes vaccines targeting secreted virulence factors, cell wall components, membrane proteins, and post-lysis effector cytoplasmic proteins, detailing their preclinical and clinical development progress. Finally, it discusses core challenges hindering clinical translation, including weak immunogenicity, population heterogeneity, and rapid antigenic evolution, as well as future research directions. Recombinant subunit vaccines have made significant strides from proof-of-concept to late-stage clinical development. Future efforts should focus on optimizing antigen targets, developing novel adjuvants, and addressing population-specific immune disparities to advance the clinical translation of safe, effective, and broad-spectrum antifungal recombinant subunit vaccines.
Australian adults' views on influenza vaccination: Implications for communication and service quality from a qualitative study.
Christou-Ergos M, Sabahelzain MM, Bolsewicz KT … +4 more , Kaufman J, Steffens M, Danchin M, Leask J
Vaccine · 2026 Jun · PMID 42314308 · Publisher ↗
Despite ongoing federal and state initiatives, influenza vaccination coverage in Australia remains suboptimal, with reported uptake declining across all age groups and priority populations since 2020. In 2025, The Nation...
Despite ongoing federal and state initiatives, influenza vaccination coverage in Australia remains suboptimal, with reported uptake declining across all age groups and priority populations since 2020. In 2025, The National Vaccination Insights Project conducted in-depth interviews with Australian adults to explore their views on influenza vaccination and understand their decision-making and access support needs to receive an influenza vaccine. Fifteen participants were recruited through an agency to participate in in-depth interviews between May and June 2025, guided by the World Health Organization's Behavioural and Social Drivers of Influenza Vaccination toolkit. A maximum variation purposive sampling strategy was used to capture diverse perspectives. Transcripts were analysed in NVivo 14 using the Framework method, focusing on what people need to feel informed, supported, and comfortable when making vaccination decisions. Two major themes emerged: (i) communication and (ii) service delivery needs, which together formed a supportive vaccination environment. Participants emphasised the need for timely, context-specific information, opportunities for dialogue with health professionals, peers, and communities, and prompts to encourage vaccination. They also highlighted the importance of consistent, patient-centred services that are convenient and affordable. Efforts to improve influenza vaccine uptake should prioritise creating opportunities for dialogue about vaccination and equity in vaccination service access and quality. In health settings, providers should elicit conversations about adult vaccines. In community settings, experts can provide opportunities for engagement and information and ensure convenient, affordable vaccination with service locations and hours integrated into people's routines. To ensure consistent service delivery, staff training may be needed with an emphasis on patient-centred communication and technical competence. This study provides important findings to inform policy and practice, highlighting the need to simultaneously address both communication and service needs to support sustained improvements in adult influenza vaccination coverage.
Booster vaccine reduces BCG-primed mice's protection against primary Mycobacterium tuberculosis infection by raising IL-10 levels.
Lei Q, Lin X, Yao Z … +8 more , Fu H, Wang Y, Yuan Y, Ouyang Q, Xu X, Cao J, Gan M, Fan X
Vaccine · 2026 Jun · PMID 42308982 · Publisher ↗
BACKGROUND: Around 90% of global tuberculosis (TB) new cases occur in adolescents and adults. The BCG vaccine, which is widely administered to infants, is inadequate for adult protection, underscoring the necessity for d...
BACKGROUND: Around 90% of global tuberculosis (TB) new cases occur in adolescents and adults. The BCG vaccine, which is widely administered to infants, is inadequate for adult protection, underscoring the necessity for developing an effective booster vaccine for adult TB prevention. However, the effectiveness of these booster vaccines, especially against primary Mycobacterium tuberculosis (M.tb) infection, remains contentious, and their underlying mechanisms are not fully understood. Emerging evidence, including our previous findings, suggests that interleukin-10 (IL-10)-mediated immune regulation may influence T cell responses following booster immunization and potentially contribute to the limited efficacy observed in preventing primary M.tb infection, although this remains to be further clarified. METHODS: This study evaluated subunit vaccines incorporating different M.tb antigens (A1D4 or CMFO) and adjuvants (DMT or DT) as booster interventions in mice previously primed with BCG. qRT-PCR was employed to assess IL-10 mRNA levels, FACS and ICS were used to detect IL-10 positive cell populations in lymph nodes, spleen, and lungs one to three weeks following the booster administration. Additionally, the effects of inhibiting IL-10 receptor signaling using a monoclonal antibody (mAb) on T cell responses and the protective efficacy against aerosolized M.tb infection were further explored. RESULTS: The administration of the same adjuvant DMT in combination with different recombinant antigens A1D4 and CMFO, or with a different adjuvant, DT, to formulate CMFO/DT as booster vaccines in BCG-primed mice, led to an increase in IL-10 levels in the lymph nodes, spleen, and lungs within three weeks. This occurred despite variations in expression levels, expression sites, and expression timings. Specifically, only modest increases in IL-10 levels were observed in the DMT-adjuvanted groups, whereas a more pronounced elevation was detected in the DT-adjuvanted group. This increase in IL-10 was primarily attributed to its expression by T and Th cells in the lungs. Blocking IL-10 signaling using mAb enhanced the resistance of mice, which had received the BCG prime-CMFO/DT boost, against aerosol infection with 300 CFU of M.tb. This enhancement was achieved by increasing the presence of antigen-specific and memory CD4 T cells in the lungs. CONCLUSION: The adjuvant and antigen composition of the booster vaccine influenced IL-10 expression following BCG priming. While IL-10 induction was relatively modest in the DMT-adjuvanted groups and was not associated with a marked change in protective efficacy, elevated IL-10 levels in the DT-adjuvanted group were accompanied by improved protection upon IL-10 blockade. These results indicate that IL-10 may contribute to the modulation of vaccine-induced immunity in a context-dependent manner. Thus, IL-10 has the potential to serve as an auxiliary biomarker for the preliminary assessment of booster vaccine performance, although its utility requires further validation.
Engineered OMVs of Salmonella displaying PlpE antigen provide effective protection against Pasteurella multocida infection in mice.
Luo Z, Gu L, Du Z … +6 more , Cao Z, Zhu B, Zhang Z, Cao S, Li Y, Zhou G
Vaccine · 2026 Jun · PMID 42308981 · Publisher ↗
Pasteurella multocida is a major zoonotic pathogen that contributes to progressive atrophic rhinitis and the porcine respiratory disease complex in pigs, leading to significant economic losses in the swine industry. Curr...
Pasteurella multocida is a major zoonotic pathogen that contributes to progressive atrophic rhinitis and the porcine respiratory disease complex in pigs, leading to significant economic losses in the swine industry. Current vaccines show limited efficacy and safety concerns. Here, we developed an OMV-based antigen display system using the signal peptide of OmpD derived from Salmonella Typhimurium to present the protective antigen PlpE. The engineered OMVs enabled surface localization of PlpE and were evaluated via intranasal immunization in mice. Immunization induced strong antigen-specific IgA and IgG responses, along with a Th1/Th17-biased cellular response. The resulting serum exhibited complement-dependent bactericidal activity against P. multocida. Upon challenge with a 10× LD dose, vaccinated mice showed significantly improved survival (80%) and reduced tissue damage. These findings demonstrate that engineered OMVs represent an effective antigen delivery platform for the control of porcine pasteurellosis.
Effectiveness of recombinant zoster vaccine against herpes zoster and postherpetic neuralgia: a systematic review and meta-analysis of post-licensure observational studies.
Mbinta JF, Awuni PMA, Muhammed Basheer ST … +7 more , Generao HK, Su'a-Tavila A, Bowe S, Harrison A, Sporle A, French N, Simpson CR
Vaccine · 2026 Jun · PMID 42308980 · Publisher ↗
BACKGROUND: Herpes zoster causes substantial morbidity in older and immunocompromised adults. The recombinant zoster vaccine is preferentially recommended, but policy decisions increasingly require real-world evidence on...
BACKGROUND: Herpes zoster causes substantial morbidity in older and immunocompromised adults. The recombinant zoster vaccine is preferentially recommended, but policy decisions increasingly require real-world evidence on effectiveness across diverse populations, dosing patterns, and potential waning of protection over time. METHODS: We conducted a systematic review and meta-analysis of observational studies (cohort and case-control) assessing recombinant zoster vaccine effectiveness among adults (≥18 years). Analytical observational studies published in any language between Jan 1, 2017, and Oct 31, 2025, were eligible. Methodological quality was assessed using the Joanna Briggs Institute standardised critical appraisal instruments. This study is registered on PROSPERO (CRD420251266323). FINDINGS: A vaccine effectiveness of 80·0% (95% Confidence Intervals [CI]: 74·1-84·5) was found for immunocompetent adults and 64·3% (95 CI: 61·4-67·0) for immunocompromised adults. Vaccine effectiveness after four years was 73·0% (68·0-76·0). For people with autoimmune diseases, vaccine effectiveness was 66·2%, 95% CI 62·7-69·5). Similar vaccine effectiveness was found for adults with diabetes (66·6%, 41·8-80·9), liver disease (62·7%, 50·4-72·0), and older adults (75·1% among ≥80 years). Pooled vaccine effectiveness for postherpetic neuralgia for the immunocompetent population was 84·7% (95% CI 60·9-94·0) and for immunocompromised populations was 38·7% (95% CI 19·1-53·5). Subgroup and complication estimates were based on fewer studies and, where evidence was sparse or outcome definitions varied across datasets, should be interpreted as exploratory. Substantial heterogeneity (I ≥ 75%) was observed in 59% of the meta-analyses. CONCLUSION: For all at-risk groups, the recombinant zoster vaccine provides sustained clinically meaningful real-world benefit in preventing herpes zoster. Evidence for protection against complications and in some subgroups is supportive but limited, particularly where estimates are based on few studies or variable outcome definitions.
Global misinformation, local consequences: conspiracy theory endorsement and a graded association with COVID-19 vaccine refusal across Nigeria.
Asaga PM, Kroeger A, Yako A … +1 more , Makpo J
Vaccine · 2026 Jun · PMID 42308979 · Publisher ↗
BACKGROUND: Conspiracy theories about COVID-19 vaccines circulated widely during the pandemic, yet their prevalence and association with vaccine refusal in sub-Saharan Africa remain poorly quantified. Understanding how g...
BACKGROUND: Conspiracy theories about COVID-19 vaccines circulated widely during the pandemic, yet their prevalence and association with vaccine refusal in sub-Saharan Africa remain poorly quantified. Understanding how global misinformation narratives shape vaccination acceptance in low- and middle-income settings is relevant to future pandemic preparedness. METHODS: We conducted a cross-sectional survey between October 2023 and April 2024, recruiting 870 adults through convenience sampling across Nigeria's six geopolitical regions. COVID-19 vaccines had been available in the country since 2021, but national uptake remained low throughout this period. Structured face-to-face interviews assessed vaccine intentions, endorsement of specific conspiracy beliefs, information sources, and trust networks. Multivariable logistic regression identified factors independently associated with conspiracy endorsement and vaccine refusal. RESULTS: Of 870 participants, 742 (85.3%) were vaccine-hesitant, and 89.4% of these endorsed at least one conspiracy theory. Microchip or tracking device theories were the most frequently cited concern (32.1%). Overall vaccine acceptance was 14.7%. A graded inverse association was observed: each additional conspiracy theory endorsed was associated with an average 69% lower odds of vaccine acceptance (aOR 0.31, 95% CI 0.25-0.39; p for trend <0.001). In multivariable analysis, conspiracy endorsement was the factor most strongly associated with refusal (aOR 0.11, 95% CI 0.06-0.21). Its inclusion in the model substantially attenuated the coefficients for education and region, which suggests that these sociodemographic associations with refusal may be partly accounted for by differential conspiracy endorsement. CONCLUSIONS: COVID-19 vaccine conspiracy theories were widespread in Nigerian communities well into the national vaccination campaign, at a time of persistently low uptake, and represented the factor most strongly associated with refusal. The graded association between conspiracy endorsement and refusal, and the attenuation of sociodemographic predictors after adjustment for conspiracy beliefs, suggest that counter-misinformation strategies could be a high-yield component of future pandemic vaccine campaigns.
Behavioural and social drivers of HPV vaccine uptake in Tonga: a mixed-methods study using the WHO BeSD framework and Talanoa in a Pacific Island setting.
Alamgir M, Randimbivololona J, Patelisio PN … +4 more , Tukia O, Fifita ST, Kafoa ST, Manoncourt E
Vaccine · 2026 Jun · PMID 42308978 · Publisher ↗
BACKGROUND: Small Pacific Island nations sustain a disproportionate cervical cancer burden. Despite an excellent routine immunization program, HPV vaccine coverage in Tonga remains consistently low after a decade of prog...
BACKGROUND: Small Pacific Island nations sustain a disproportionate cervical cancer burden. Despite an excellent routine immunization program, HPV vaccine coverage in Tonga remains consistently low after a decade of programming. We used the WHO Behavioural and Social Drivers (BeSD) framework to identify drivers of HPV vaccine uptake among caregivers and to examine the underlying contextual mechanisms shaping vaccination decisions in this Pacific Island setting. METHODS: A mixed-methods cross-sectional study was conducted in August 2025 across all five main island groups of Tonga. We enrolled 398 caregivers of girls aged 9-14 years through stratified multistage cluster sampling. Multivariable logistic regression identified independent predictors of HPV vaccination uptake, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI). We conducted 25 Talanoa sessions, a traditional Pacific approach for inclusive dialogue, with purposively sampled key informants. Findings were analyzed thematically using an inductive-deductive approach. RESULTS: Six BeSD-aligned predictors independently predicted vaccine uptake. Knowing the vaccine was free made the biggest difference (aOR 3.21, 95% CI 2.05-5.02; p < 0.001), indicating a communication gap regarding cost. Other significant drivers were HPV awareness (aOR 2.85, p < 0.001), trust in health workers (aOR 2.41, p < 0.001), concern about cervical cancer (aOR 2.17), social responsibility (aOR 1.94), and ease of access (aOR 1.76). Talanoa sessions revealed three themes: 1) gendered household decision-making requiring approval from husbands or elders; 2) school-based consent procedures that felt rushed or semi-coercive; and 3) the decisive gatekeeping role of religious and community leaders. INTERPRETATION: With substantial contextual adaptation, the BeSD framework is useful in Pacific Island settings. Greater coverage gains require improving provider recommendation practices, clarifying vaccine cost and purpose, institutionalizing school-based consent processes, and strategic engagement of community and faith leaders. Despite high trust in health workers (87.9%), only 41.5% of caregivers reported receiving a provider recommendation, a gap that targeted training could address.
Caregiver COVID-19 vaccine status and its influence on pediatric vaccination decisions in a US cohort.
Ricke IJ, Ward C, Spaulding AB … +2 more , Sherwood NE, Nguyen RHN
Vaccine · 2026 Jun · PMID 42308977 · Publisher ↗
BACKGROUND/OBJECTIVES: Despite availability of safe and effective COVID-19 vaccines for children, uptake of this vaccine remains low in the United States. Caregiver attitudes and behaviors play a key role in child vaccin...
BACKGROUND/OBJECTIVES: Despite availability of safe and effective COVID-19 vaccines for children, uptake of this vaccine remains low in the United States. Caregiver attitudes and behaviors play a key role in child vaccine decisions, yet little is known about the reasons for vaccine refusal within families or the relationship between COVID-19 vaccine and routine childhood immunization refusal. This study examined 1) associations between caregiver and child COVID-19 vaccination status, 2) alignment of reasons for vaccine non-acceptance between the caregiver themselves and for their child, and 3) associations between COVID-19 vaccine non-acceptance and refusal or delay of routine childhood vaccinations. METHODS: We analyzed data from 6395 families in the NIH ECHO Cohort with self-reported caregiver and child COVID-19 vaccination status between December 2021 and August 2023. Generalized estimating equations were used to assess associations while accounting for cohort clustering. RESULTS: Of the 6395 families, 25% of caregivers had not accepted the COVID-19 vaccine for themselves, and 59% had not accepted the vaccine for any of their children. Children were more likely to be unvaccinated when their caregivers were unvaccinated (OR: 13.2, 95% CI: 10.3-16.9). Among unvaccinated caregiver-child pairs, reasons for vaccine refusal showed strong concordance. The predominant concern among vaccinated caregivers with unvaccinated children was a belief that the COVID-19 vaccine had not been well tested in children (OR: 3.7, 95% CI: 2.3-6.0). Caregivers who refused the COVID-19 vaccination for themselves were more likely to have delayed or refused routine vaccines for their child (child unvaccinated for COVID-19: OR: 1.8, 95% CI: 1.4-2.1); caregiver unvaccinated for COVID-19: OR 2.8, 95% CI: 2.2-3.4). CONCLUSIONS: COVID-19 vaccine status among caregivers was strongly associated with child COVID-19 vaccine uptake and broader vaccine behaviors. Addressing shared safety concerns and building caregiver trust in vaccines is essential for improving pediatric vaccination coverage.
From community mobilisation to school vaccination: experiences from Cameroon's first Expanded Programme on Immunisation-led school-based HPV campaign.
Haddison E, Nebongo D, Amponsah-Dacosta E
Vaccine · 2026 Jun · PMID 42308976 · Publisher ↗
BACKGROUND: The HPV vaccine was introduced into Cameroon's Expanded Programme on Immunisation in 2020 targeting 9 year-old girls and later boys in 2023, however, implementation has relied mainly on community-and facility...
BACKGROUND: The HPV vaccine was introduced into Cameroon's Expanded Programme on Immunisation in 2020 targeting 9 year-old girls and later boys in 2023, however, implementation has relied mainly on community-and facility-based strategies, resulting in low coverage rates. School-based vaccination is an effective strategy for reaching adolescents; however, it had not previously been implemented nationally. This study describes the implementation and outcomes of the first EPI-led school-based HPV vaccination campaign in Cameroon. METHODS: The campaign was conducted in nine districts across the Centre, Littoral, South and West regions. A multisectoral coordination committee oversaw planning and implementation. Community engagement activities, school-based health talks and door-to-door sensitisation, were conducted prior to vaccination. Vaccination teams administered either quadrivalent or nonavalent HPV vaccines in schools. School participation and vaccination coverage among eligible adolescents were documented. RESULTS: A total of 300 schools participated, including 245 primary schools (79%) and 55 secondary schools (63%). Community sensitisation activities reached 44,118 people, while 816 individuals attended community engagement meetings. Among adolescents identified by social mobilisers, 13,189 girls aged 9-14 years and 10,300 boys aged 9-11 years were identified. Of these, 9392 girls (48.3%) and 4963 boys (48.2%) received the HPV vaccine. Misclassifying previous vaccinees as part of the denominator contributed to underestimation of coverage. CONCLUSION: This campaign demonstrates the feasibility of implementing a school-based HPV vaccination programme in Cameroon supported by strong community engagement and multisectoral collaboration. Integrating schools into HPV vaccination strategies could significantly improve adolescent vaccine uptake and contribute to cervical cancer prevention efforts.
Infectious disease hospitalization rates before and after introduction of vaccine against human papillomavirus in Denmark, Norway, and Sweden: controlled interrupted time series analyses.
Laake I, Feiring B, Sørup S … +5 more , Englund H, Nieminen H, Cardél LG, Benn CS, Trogstad L
Vaccine · 2026 Jun · PMID 42308975 · Publisher ↗
BACKGROUND: It has been suggested that non-live vaccines may increase the risk of non-targeted infections, especially in girls. We examined whether the introduction of non-live human papillomavirus (HPV) vaccine was asso...
BACKGROUND: It has been suggested that non-live vaccines may increase the risk of non-targeted infections, especially in girls. We examined whether the introduction of non-live human papillomavirus (HPV) vaccine was associated with an increased rate of infectious disease hospitalization among girls in Denmark, Norway, and Sweden. METHODS: Using data from national patient registries, we performed controlled interrupted time series analyses including an intervention group (13-year-old girls in Denmark, 8th-grade girls in Norway, 7th grade girls in Sweden) and a control group not offered HPV vaccine (boys of the same age/grade). Infectious disease hospitalization rates were modelled using negative binomial regression, and the level change, i.e. the incidence rate ratio corresponding to the relative change to the rate's underlying trend following introduction of HPV vaccine, was estimated. RESULTS: For infectious disease hospitalizations of any duration, the level change among girls and boys, respectively, was 1.21 (95% confidence interval (CI) 0.94-1.57) and 0.73 (95% CI 0.56-0.96) in Denmark; 1.21 (95% CI 0.94-1.56) and 1.14 (95% CI 0.88-1.49) in Norway; and 0.83 (95% CI 0.65-1.07) and 0.72 (95% CI 0.56-0.92) in Sweden. For hospitalizations with ≥2 overnight stays, the level change was 1.05 (95% CI 0.71-1.56) and 0.81 (95% CI 0.54-1.20) among Danish girls and boys, respectively, whereas the results in Norway and Sweden were similar to the results for hospitalizations of any duration. CONCLUSION: Changes to the rate following introduction of HPV vaccine were similar among girls and boys in Norway and Sweden, in line with there being no association between HPV vaccination and infectious disease hospitalizations. The difference between Danish girls and boys seems unlikely to be attributable to HPV vaccine, given the Norwegian and Swedish results. Overall, our study does not support that HPV vaccination increases risk of infectious disease hospitalization.
Breakthrough varicella infection: a retrospective cohort study based on large-scale real-world data in Guangxi, China, 2014-2025.
Wang J, Li S, Zhou W … +7 more , Huang J, Huang Y, He W, Nong X, Ning C, Lan G, Zeng X
Vaccine · 2026 Jun · PMID 42308974 · Publisher ↗
BACKGROUND: Although varicella is a vaccine-preventable disease, the number of breakthrough infection cases has been increasing in recent years. However, data remain limited regarding the dynamics of breakthrough infecti...
BACKGROUND: Although varicella is a vaccine-preventable disease, the number of breakthrough infection cases has been increasing in recent years. However, data remain limited regarding the dynamics of breakthrough infections, especially in relation to vaccine dosage and dosing schedules. METHODS: This retrospective study analyzed surveillance data from Guangxi, China, from 2014 to 2025. Varicella cases were derived from the China Information System for Disease Control and Prevention (CISDCP), while varicella vaccination records were extracted from the Guangxi Immunization Information System (IIS). Cumulative incidence of breakthrough varicella was estimated using the Kaplan-Meier method, and cox proportional hazards models with time-varying variables were used to evaluate factors associated with breakthrough varicella. RESULTS: Of 5,755,799 varicella vaccine recipients, 70,013 (1.22%) had breakthrough infections: 63,619 (1.71%) among one-dose, 6382 (0.31%) among two-dose, and 12 (0.15%) among three-dose recipients. The cumulative breakthrough varicella rate was 0.09% at 12 months, exceeding 1.00% at 72 months, and 2.15% at 132 months. Compared with an interval of 42 days to <1 year since the last dose, the adjusted hazard ratios (aHRs) for breakthrough varicella increased progressively with longer intervals: 1.31 (95% CI: 1.22-1.40) for 12-<24 months, 1.94 (95% CI: 1.82-2.07) for 24-<36 months, and 5.01 (95% CI: 4.71-5.32) for ≥36 months (all P < 0.001). Receipt of a second dose was associated with a lower hazard than one dose (aHR = 0.29; 95% CI: 0.27-0.30; P < 0.001), after adjustment for age, sex, and calendar year. CONCLUSION: Our study confirms waning immunity after varicella vaccination. Increasing two-dose coverage, optimizing the vaccination interval, and including the vaccine in national programs are key to reducing breakthrough infections. Prospective studies with immune monitoring are needed to assess long-term protection and the optimal dosing interval.
Behavioural and social drivers of childhood immunisation uptake in sub-Saharan Africa: A rapid qualitative review.
Christian E, Tinessia A, Zhu J … +4 more , Chutiyami M, Mahimbo A, King C, Abdi I
Vaccine · 2026 Jun · PMID 42302354 · Publisher ↗
BACKGROUND: Immunisation is one of the most successful public health interventions, yet many people in sub-Saharan Africa continue to face significant barriers to accessing vaccination. The WHO's Behavioural and Social D...
BACKGROUND: Immunisation is one of the most successful public health interventions, yet many people in sub-Saharan Africa continue to face significant barriers to accessing vaccination. The WHO's Behavioural and Social Drivers Framework conceptualises factors influencing vaccination decision-making and provides a structured approach for synthesising evidence. This rapid review examines the factors shaping childhood vaccination decisions in sub-Saharan African contexts using the WHO Behavioural and Social Drivers (BeSD) framework. METHODS: We conducted a rapid review, searching three databases: Ovid Medline, Ovid Global Health and African Index Medicus for qualitative and mixed methods with a qualitative component examining childhood immunisation in sub-Saharan Africa. A total of 2441 records were identified, and 617 full texts were assessed for eligibility. Findings were first inductively coded using thematic analysis and then, deductively mapped against the BeSD framework. RESULTS: A total of forty-eight studies were included in this review. Vaccine confidence and perceived benefits were influenced by previous experiences, trust in health systems and government. Practical issues surrounding vaccination delivery remain a significant limitation to the provision of childhood vaccinations. Frequently cited barriers included the indirect costs of vaccination, unclear scheduling and imperfect relationships with healthcare providers. Motivation to get vaccinations was generally reported as high, but supply side barriers often overrode this intent to take up recommended vaccinations. CONCLUSIONS: This review reflects evidence that improving childhood vaccination coverage in Sub-Saharan African contexts requires moving beyond vaccine hesitancy as an individual-level problem. Trusted community intermediaries, particularly community health workers, religious leaders, and traditional authorities, were described as important in bridging informational and relational gaps. Effective immunisation programming most successfully received by caregivers integrated approaches that address health system gaps, engage entire households, leverage existing community trust networks and address gender dynamics.
Incidence of outcomes relevant to vaccine safety monitoring in the general population, after influenza vaccination, and after respiratory infections: a descriptive analysis of four US claims databases, 2022-2023.
Bush C, Desai S, Wang H … +9 more , Hsu WC, Newbern EC, Toyip A, Grace S, Mues KE, Arakaki B, Khamamkar V, Esposito DB, Zhou CK
Vaccine · 2026 Jun · PMID 42296834 · Publisher ↗
BACKGROUND: Background incidence rates (IRs) of safety outcomes in the absence of vaccination of interest and IRs following the infection targeted by the vaccine, are integral for contextualizing vaccine benefit-risk. As...
BACKGROUND: Background incidence rates (IRs) of safety outcomes in the absence of vaccination of interest and IRs following the infection targeted by the vaccine, are integral for contextualizing vaccine benefit-risk. As new respiratory vaccines are developed, contemporaneous IR estimates for outcomes commonly assessed in vaccine safety surveillance are needed in the COVID-19 endemic era. METHODS: This retrospective cohort study used four administrative claims data sources in the United States (HealthVerity Closed Claims, Optum's de-identified Clinformatics® Data Mart, Humana and Medicare Fee-For-Service) to estimate IRs for 30 safety outcomes across five organ systems between 1 August 2022 and 31 July 2023. Analyses were conducted overall and stratified by age and sex in five cohorts: the general population, influenza vaccine recipients, and those with medically attended SARS-CoV-2, respiratory syncytial virus, or influenza infection. RESULTS: IRs following influenza vaccination were generally similar to or lower than those in the general population, whereas rates after respiratory infections were generally higher and confounded by marked baseline differences. Among adults ≥65 years, heart failure, atrial fibrillation, ischemic coronary artery disease, and venous thromboembolism had the highest IRs across cohorts. Among adults aged 18-64 years, seizure, anaphylaxis and cardiovascular outcomes were most frequent after respiratory infections. The highest IRs in children were febrile seizures in those ≤5 years and seizures in <18 years; most other outcomes were rare. IRs were similar to or higher in males than females, except for autoimmune disorders. CONCLUSION: This study estimated IRs for 30 safety outcomes relevant to vaccine safety monitoring in a COVID-19 endemic period. Variation across demographic groups and cohorts underscores the importance of accounting for confounders including age and sex when estimating expected rates. Elevated IRs after respiratory infections provide context for future benefit-risk assessments for vaccines targeting these viruses before more rigorous adjusted analyses become available.
Adverse events following immunization with human papillomavirus vaccine: post-marketing surveillance in China, 2021-2024.
Zhang L, Li K, Li Y … +6 more , Fan C, Li Y, Ren M, Cao L, Yu W, Yin Z
Vaccine · 2026 Jun · PMID 42296833 · Publisher ↗
BACKGROUND: Human papillomavirus (HPV) vaccine has been authorized by the National Medical Products Administration for marketing in China since 2016. This study analyzed the adverse events following immunization (AEFI) w...
BACKGROUND: Human papillomavirus (HPV) vaccine has been authorized by the National Medical Products Administration for marketing in China since 2016. This study analyzed the adverse events following immunization (AEFI) with all HPV vaccines available in China during 2021-2024: three imported and two domestic HPV vaccines, which were all non-program vaccines approved for females only during the study period. METHODS: We obtained all AEFI reports and numbers of HPV vaccine doses administered during 2021-2024 from the Chinese National Immunization Information System (CNIIS). We used descriptive epidemiological methods to analyze characteristics and reporting incidence (RI) of HPV vaccine AEFI reports. RESULTS: During the study period, 163.57 million doses of HPV vaccine were administered and 23,890 HPV vaccine AEFI were reported, for an overall RI of 14.61 AEFI reports per 100,000 doses. Respective AEFI RIs for 9-12-years-old, 13-17-years-olds, 18-30-years-olds, and 31-46-years-olds were 15.01, 16.37, 14.00, and 14.77 per 100,000 doses administered. For bivalent, quadrivalent and 9-valent HPV vaccines, respective RIs were 8.49, 12.65, and 20.50 per 100,000 doses. Most AEFI reports were for common vaccine reactions - injection site reactions (redness/swelling, 6.31 reports per 100,000 doses) and systematic reactions (fever, 3.71 reports per 100,000 doses). The reporting incidence of rare vaccine reactions was 0.49 per 100,000 doses administered, with allergic rash most frequently reported. RIs of serious AEFI and serious rare vaccine reactions were 0.13 and 0.05 per 100,000 doses administered, respectively. CONCLUSIONS: The immunization safety profile of HPV vaccines available in China during 2021-2024 was acceptable based on this national AEFI data analysis. Serious adverse vaccine reactions were extremely rare; no new or clinically meaningful safety concerns were found.
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