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PubMed2026

Adherence and efficacy of the 0 - 7 - 21-day versus the 0 - 1 - 6-month hepatitis B vaccination schedules among people who use drugs: a two-year randomized controlled trial.

BACKGROUND: To compare the adherence and efficacy between the 0 - 7 - 21-day and the 0 - 1 - 6-month hepatitis B virus (HBV) vaccination schedules among people who use drugs (PWUD) in China. RESEARCH DESIGN AND METHODS: A randomized controlled trial was conducted in 1261 HBV-susceptible PWUD from compulsory isolated detoxification centers (CIDCs) and methadone maintenance treatment (MMT) clinics in Xi'an. A 20 µg per-dose vaccine was used. HBV surface antibody (anti-HBs), surface antigen, and core antibody were tested at months 7, 15, and 22 after the first dose. RESULTS: Third-dose coverage was significantly higher in the 0 - 7 - 21-day group (74.40%) than in the 0 - 1 - 6-month group (51.58%, p < 0.001), mainly driven by participants from CIDCs (77.75% vs. 45.69%). Anti-HBs positive rates at months 7, 15, and 22 among participants who completed all three doses were significantly higher for the 0 - 1 - 6-month schedule (90.71%, 76.82%, and 67.35%) than for the 0 - 7 - 21-day schedule (74.23%, 49.40%, and 40.95%; all p < 0.001). HBV infection incidence was similar between schedules, but significantly different between vaccinees and non-vaccinees (p = 0.018). CONCLUSIONS: The 0 - 7 - 21-day schedule substantially enhances three-dose completion in PWUD, but induces a notably weaker anti-HBs response and persistence. Schedules should be selected based on the management models for PWUD and their individual characteristics. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR1900022403).

Humans↗

PubMed2026

Immunogenicity and safety of inactivated TZ84- vs. HM175-based hepatitis A vaccines in pediatric populations: A systematic review and meta-analysis.

Individual studies indicate stronger and persistent long-term immunogenicity with TZ84-based than HM175-based hepatitis A vaccines. This systematic review and meta-analysis compared immunogenicity and safety of inactivated TZ84- and HM175-based hepatitis A vaccines in children and adolescents. Studies involving adults, immunocompromised populations, non-comparative designs, non-English publications, and studies with non-extractable outcomes were excluded. MEDLINE/PubMed, Google Scholar, other electronic databases, and grey literature were searched (September-October 2025). Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, and meta-analyses were performed where appropriate. Seven publications arising from four randomized cohorts (total participants: 3,282) reporting seroconversion rates (SCRs), geometric mean concentrations (GMCs), long-term seroprotection, and adverse events (AEs) were identified. Pooled analyses demonstrated higher SCRs and GMCs with TZ84 than HM175-based vaccines following both one and two doses. SCRs at 1 month [odds ratio (OR): 3.05; 95% confidence interval (CI): 1.88-4.96] and GMCs at 7 months [standardized mean difference (SMD): 0.88; 95% CI: 0.18-1.58; p = .01] both favored TZ84-based vaccines. Long-term follow-up (up to 186 months/15.5 y) showed higher reported anti-HAV antibody concentrations for TZ84-based vaccines. The AEs were comparable between vaccine types (RR: 0.95; 95% CI: 0.76-1.20; p = .69). Evidence was limited by the small number of unique randomized cohorts, geographic concentration in China, heterogeneity across studies, and reliance on surrogate immunogenicity outcomes. Overall, available evidence suggests that TZ84-based hepatitis A vaccines (HAPIBEV™/HEALIVE®) are associated with higher reported antibody responses and greater reported antibody persistence than the HM175-based vaccine (HAVRIX®) in children and adolescents, with comparable safety profiles.Registration: PROSPERO CRD420251154480.

Humans↗

PubMed2026

Safety of a quadrivalent meningococcal conjugate vaccine (MenACYW-TT) administered concomitantly with routine pediatric vaccines in healthy infants and toddlers in USA and Puerto Rico: Results from a Phase III, randomized, active-controlled study.

MenACYW-TT, a quadrivalent meningococcal tetanus toxoid-conjugate vaccine, is approved for prevention of invasive meningococcal disease in infants ≥ 6 weeks of age in the USA. This Phase III study (NCT03673462; September 17, 2018 - March 16, 2023) evaluated the safety of MenACYW-TT compared with a licensed quadrivalent meningococcal oligosaccharide diphtheria CRM197-conjugate vaccine (MenACWY-CRM) when administered concomitantly with routine pediatric vaccines in healthy infants and toddlers in a four-dose series (3+1 schedule). Participants were randomized 3:1 to receive MenACYW-TT (Group 1; n = 2080) or MenACWY-CRM (Group 2; n = 697) at 2, 4, 6, and 12 months of age, with concomitant administration of routine pediatric vaccines (DTaP5-IPV/Hib, PCV13, rotavirus, hepatitis B, MMR, and varicella vaccines). Safety assessments included immediate unsolicited adverse events within 30 minutes post-vaccination, solicited injection site and systemic reactions within 7d, unsolicited AEs within 30d, serious adverse events (SAEs) including adverse events of special interest (AESIs), and medically attended adverse events (MAAEs) throughout the study. MenACYW-TT and MenACWY-CRM were overall well tolerated, and safety profiles were comparable. Solicited injection site reactions occurred in 84.9% and 84.6% of participants in Groups 1 and 2, respectively; solicited systemic reactions in 87.1% and 88.2%, respectively. During the entire study, 5.2% in Group 1 and 3.0% in Group 2 experienced at least one SAE; 0.9% and 0.1%, respectively, reported at least one AESI. Three deaths occurred in Group 1. All SAEs, AESIs, and deaths were unrelated to study vaccines. This study supports the safety profile of MenACYW-TT in infants and toddlers aged ≥ 6 weeks.Study registration: Clinicaltrials.gov: NCT03673462; EudraCT: 2019-004459-35.

Child, Preschool↗

PubMed2026

Vaccine preferences and their role for vaccine confidence and uptake: a meta-ethnography.

Vaccine confidence and uptake are influenced by individuals' preferences regarding vaccine composition, quality, or administration pathways. However, literature synthesizing available qualitative insights into individuals' vaccine preferences remains limited. We therefore conducted a meta-ethnographic systematic review of the qualitative literature on vaccine preferences to identify opportunities for enhancing vaccine confidence and uptake. We implemented a comprehensive search strategy and screened 5,528 studies across seven research databases published between 2001 and 2023. We identified and synthesized 97 qualitative articles to delineate factors influencing consumers' vaccine preferences. Our findings revealed four primary domains shaping individuals' vaccine preferences: Product, Place, Price, and Promotion. First, individuals' preferences for vaccines often hinge on perceived quality and safety of the product itself, which can, for example, be associated with vaccine brand or origin, especially in the case of novel vaccines. Second, people prioritize convenience in terms of vaccination sites and delivery methods (wanting vaccinations offered at their doorstep or in local peripheral clinics); evidence regarding preferred groups to administer the vaccines was mixed. Third, the price of vaccines and the secondary costs associated with vaccination played a role in uptake considerations. Finally, both the sources of information (such as healthcare workers, community volunteers, and religious authorities) and the methods of promoting vaccine information (including face-to-face consultations during clinic visits and the distribution of leaflets or banners), emerged as crucial factors shaping decision-making processes. Overall findings highlight the importance of addressing multifaceted preferences to enhance vaccine confidence and uptake. By understanding individuals' vaccine preferences, strategic recommendations can be developed to optimize vaccination programs and ensure acceptability and utilization.

Humans↗

PubMed2026

Efficacy of NAs in combination with Peg-IFN for functional cure in patients with CHB: a meta-analysis of RCTs.

BACKGROUND: The goal of treating chronic hepatitis B (CHB) is to achieve functional cure. We aimed to evaluate the efficacy of the combination of nucleoside (acid) analogues (NAs) and pegylated interferon (Peg-IFN) on the functional cure of CHB patients at the EOT and at the EOF. METHOD: PubMed, Embase, and Web of Science were searched systematically up to March 15, 2025. Sixteen RCTs on CHB patients receiving combination or monotherapy were included. RESULT: Compared with NAs treatment, the NAs combined with Peg-IFN treatment group significantly improved HBsAg clearance rate (RR: 14.05, 95% CI 6.13-32.20) and HBsAg seroconversion rate (RR: 12.82, 95% CI 5.08-32.33) at the EOT. Moreover, compared with NAs treatment, the NAs combined with Peg-IFN treatment group significantly improved HBsAg clearance rate (RR: 7.70, 95% CI 4.24-13.98), HBsAg seroconversion rate (RR: 11.93, 95% CI 5.14-27.67) at the EOF. However, compared with Peg-IFN monotherapy, the combination therapy group did not show any improvement in HBsAg clearance rate, HBsAg seroconversion rate, and the rate of qHBsAg decrease > 1 log10 IU/mL at the EOT and the EOF. Moreover, in terms of safety, the Peg-IFN monotherapy group showed more ALT flares (ALT > 5 × ULN) during the treatment process. CONCLUSION: Compared with NAs therapy, Peg-IFN combined with NAs therapy significantly improves functional cure rate. However, combination therapy shows no additional advantage over Peg-IFN monotherapy in achieving functional cure. The Peg-IFN monotherapy group has a higher incidence of ALT flares than the combination therapy group.

Humans↗

PubMed2026

Transcriptomic responses of gill and intestinal tissues in Nile tilapia (Oreochromis niloticus) to bacterial infection following sequential nanoimmersion and hydrogel-based multivalent vaccination.

Bacterial pathogens, including Flavobacterium oreochromis, Aeromonas veronii, Streptococcus agalactiae, and Edwardsiella tarda, represent major infectious threats to Nile tilapia (Oreochromis niloticus). A multivalent vaccination strategy integrating cationic nanoemulsion immersion with oral hydrogel boosters was developed to investigate tissue-specific immune responses at the transcriptomic level. Gill tissues were collected following immersion challenge and intestinal tissues following intraperitoneal injection challenge, reflecting the physiologically relevant infection biology of each pathogen and the mechanistic rationale of each delivery platform. RNA sequencing (RNA-seq) generated high-quality datasets (mapping rate > 81.64%) with strong concordance to quantitative real-time PCR (qRT-PCR) validation (r = 0.83). Comparative transcriptomic analysis revealed distinct yet complementary immune signatures between tissues. Gill transcriptomes were enriched in phagosome, focal adhesion, extracellular matrix-receptor interaction (ECM-receptor interaction), and cytokine-cytokine receptor interaction pathways, accompanied by increased expression of major histocompatibility complex class I/II (MHC class I/II), mannose receptor, αVβ3 integrin, and calnexin, indicating innate activation, enhanced phagocytic capacity, epithelial barrier reinforcement, and adaptive immune coordination. Intestinal transcriptomes showed predominant enrichment of adaptive immune pathways, including the intestinal immune network for immunoglobulin (Ig) production, Forkhead box O (FoxO) signaling, and mitogen-activated protein kinase (MAPK) signaling, with increased expression of T-cell receptor (TCR), inducible T-cell co-stimulator ligand (ICOS-L), C-X-C chemokine receptor type 4 (CXCR4), and polymeric immunoglobulin receptor (pIgR), reflecting T and B cell coordination, lymphocyte trafficking, and mucosal immunoglobulin transport, alongside innate engagement through phagosome pathway enrichment. Shared upregulation of MHC class II, B-cell receptor (BCR) signaling, integrin alpha M (ITGAM), and immunoglobulin-associated components across both tissues suggests coordinated mucosal immune activation through a conserved immune module, warranting direct experimental validation. Collectively, these findings provide transcriptomic evidence that this vaccination strategy elicits an integrated, tissue-specialized immune response, advancing mechanistic understanding of gill and intestinal immunity in vaccine-induced protection of teleost fish.

Animals↗

PubMed2026

Bacteroides cellulosilyticus-derived 2-hydroxyphenylacetic acid rectifies hepatic lipid homeostasis in MASLD by targeting the PPARγ-CD36 axis.

The gut microbiota plays an important role in the occurrence and development of metabolic dysfunction-associated steatotic liver disease (MASLD), but the specific molecular mechanisms involved have not been fully elucidated. In this study, human cohort studies were performed to identify that the relative abundance of Bacteroides cellulosilyticus (B. cellulosilyticus) was significantly decreased in patients with MASLD. Through the integration of metagenomic and metabolomic analyses, it was confirmed that B. cellulosilyticus and its metabolite 2-hydroxyphenylacetic acid (2HPAA) are key factors regulating the occurrence and development of MASLD. Single-cell sequencing and lipidomic analyses revealed that 2HPAA can enter the liver through the enterohepatic circulation to exert regulatory effects. Specifically, 2HPAA inhibits the peroxisome proliferator-activated receptor γ (PPARγ) signaling pathway, thereby suppressing the expression of the fatty acid transporter CD36. Meanwhile, 2HPAA regulates lipid metabolism in hepatocytes by significantly enhancing palmitate conversion efficiency and inhibiting CD36 palmitoylation. This dual regulatory effect on CD36 expression and palmitoylation can reduce lipid accumulation in hepatocytes and ultimately alleviate MASLD progression. These findings reveal the mechanism by which B. cellulosilyticus and 2HPAA alleviate MASLD by targeting the PPARγ-CD36 pathway. This work provides a new perspective for the study of gut microbiota-host interactions in regulating liver diseases.

PPAR gamma↗

PubMed2026

A 7-mm Covered TIPS Reduces Hepatic Encephalopathy Without Increasing Rebleeding in Cirrhotic Patients With Small Liver: A Randomized Study.

BACKGROUND/AIMS: International guidelines recommend initiating transjugular intrahepatic portosystemic shunt (TIPS) placement with an 8-mm stent. However, there is an evident lack of randomized controlled trials evaluating TIPS diameters < 8 mm in cirrhotic patients with a relatively small liver. The aim of this study was to determine whether 7 mm-covered TIPS, compared with 8-mm stents, could achieve comparable shunt function with a lower incidence of hepatic encephalopathy (HE). METHODS: In this multicenter randomized controlled trial, patients with cirrhosis and relatively small liver were randomized 1:1 to receive TIPS with a 7-mm (n = 92) or 8-mm (n = 92) covered stent to prevent variceal rebleeding. The primary endpoint was the incidence of overt HE after randomization. All-cause rebleeding, orthotopic liver transplantation (OLT)-free survival and a composite of these outcomes, were designated as secondary endpoints. RESULTS: Among the 184 enrolled patients, the predominant etiologies of liver cirrhosis were hepatitis B virus infection (56.0%) and alcohol-related liver disease (20.7%). Over a median follow-up of 26.5 months, overt HE occurred in 19 patients (20.7%) in the 7-mm group and 33 patients (35.9%) in the 8-mm group. The 2-year cumulative incidence of overt HE was significantly lower in the 7-mm group than in the 8-mm group (21.4% vs. 37.2%, p = 0.02). Stent diameter, post-TIPS portosystemic pressure gradient, pre-covert HE and MELD-Na score were identified as independent risk factors for overt HE. The rates of shunt dysfunction were statistically similar between groups (8.7% vs. 8.7%, p = 1.0), as were 2-year rebleeding rates (10.9% vs. 9.8%, p = 0.81) and OLT-free survival rates (91.3% vs. 88.0%, p = 0.82). CONCLUSIONS: A 7-mm covered TIPS demonstrated comparable shunt function to an 8-mm covered stents, with a significantly lower risk of overt HE. These findings support consideration of 7-mm TIPS stents for preventing variceal rebleeding in cirrhotic patients with a small liver who are undergoing TIPS. TRAIL REGISTRATION: ClinicalTrials.gov, NCT02541825.

Humans↗

PubMed2026

Population-level impact of HPV vaccination: a global systematic review of ecological, cross-sectional, and cohort studies.

BACKGROUND: Human papillomavirus (HPV) causes approximately 4.5% of cancers globally, with the highest burden in low- and middle-income countries (LMICs). Since their introduction in 2006, HPV vaccination programs have led to substantial declines in HPV-related outcomes, although impact varies across settings. RESEARCH DESIGN AND METHODS: We conducted a systematic review to evaluate the population-level impact of HPV vaccination on HPV infection, cervical intraepithelial neoplasia grade 2 or higher (CIN2+), genital warts, invasive cervical cancer (ICC), and oropharyngeal cancer (OPC), and examined the influence of coverage, age at initiation, and vaccine type. The review followed PRISMA 2020. RESULTS: Of 13,549 records screened, 63 were included: 9 assessed HPV infection, 24 on CIN2+, 25 on genital warts, and 7 on ICC. Greatest reductions were observed in settings with at least 70% coverage and early vaccination prior to sexual debut, typically achieved through school-based programs. Reported declines ranged from 58-100% for HPV infection, 30-88% for CIN2+, 60-90% for genital warts, and 70-88% for ICC. CONCLUSIONS: HPV vaccination offers strong protection, especially when delivered early and at high coverage within schools. Expanding access and prioritizing underserved populations are essential to achieving global cancer prevention goals. Limitations include heterogeneity across designs, outcome definitions, and follow-up.

Humans↗

PubMed2026

Safety and immunogenicity of an mRNA COVID-19 vaccine administered to adults: A phase 2, randomized, active-controlled trial.

We conducted a phase 2, randomized, active-controlled, observer-blind study (NCT05960097) among healthy adults ≥18 y of age who completed a primary COVID-19 mRNA vaccination series, with or without a booster, ≥3 months earlier. Participants were randomized (1:1:1:1:1) to either receive an investigational bivalent mRNA COVID-19 vaccine encoding ancestral D614G and Omicron BA.4-5 spike proteins (CV0701 mRNA vaccine) at one of three dose levels, an investigational monovalent mRNA COVID-19 vaccine encoding the Omicron BA.4-5 spike protein (CV0601 mRNA vaccine), or a licensed Original Wuhan/Omicron BA.4-5 bivalent mRNA COVID-19 vaccine. The primary objectives were to evaluate reactogenicity, safety and immunogenicity post-vaccination. Secondary and tertiary objectives were to further evaluate humoral and cell-mediated immunity post-vaccination. In total, 425 participants were vaccinated and 381 were included in the Day 29 per-protocol immunogenicity analysis. Most solicited events were mild to moderate. No vaccine-related serious adverse events or myocarditis/pericarditis cases were reported. For the CV0701 mRNA vaccine, a dose-dependent increase in Day 29 neutralizing titers against ancestral D614G and Omicron BA.4-5 was observed. Neutralizing titers against ancestral D614G and Omicron BA.4-5 declined by Days 91 and 181, but remained above baseline. Similar immune responses were observed for the CV0601 mRNA vaccine. At Day 8, CD4+ T cells (Th1 profile) increased in all study groups and CD8+ T cells increased in all study groups, except the lowest CV0701 dose group. The CV0701 and CV0601 mRNA vaccines elicited robust humoral and cellular immunity with an acceptable safety profile, comparable to a licensed, bivalent mRNA vaccine. Clinical Trial Registration EU CT number: 2023-504596-25-00 ClinicalTrials.gov: NCT05960097.

Humans↗

PubMed2026

Ethiopia missed opportunities for vaccination study: Cluster-randomized evaluation of 5-dose measles vaccine vials and a flexible open-vial policy, 2021-2022.

INTRODUCTION: In 2024, an estimated 95,000 people died from measles globally, largely from suboptimal coverage with the measles-containing vaccine (MCV). Health workers may defer vaccinating eligible children to avoid wasting doses from 10-dose MCV vials, which must be discarded six hours after opening. These missed opportunities for vaccination (MOV) reduce coverage and timeliness. Ethiopia, which provides MCV at 9 and 15 months, considered switching to 5-dose vials. METHODS: We conducted a 15-month, randomized controlled trial with a nested cross-sectional design in Ethiopia. Sixty woredas were randomized to: (1) policy-only, instructing health workers to open 10-dose vials for any number of eligible children, with additional stock for increased wastage; (2) 5-dose switch, combining this policy with replacement of 10-dose by 5-dose vials; or (3) control (routine 10-dose practice). Household and health-facility surveys at baseline and endline assessed effects on first-dose (MCV1) and second-dose (MCV2) coverage, MCV1 timeliness, and wastage. Generalized estimating equation models estimated net intervention effects versus control. We also estimated the government cost of a nationwide 5-dose switch. RESULTS: MCV1 coverage was similar between policy-only and control (adjusted risk difference [ARD] = -1%, 95%CI: -17%, 15%), with no significant differences in MCV1 timeliness or MCV2 coverage. In the 5-dose switch group, MCV1 coverage changed little (ARD = 1%, 95%CI: -17%, 18%), but timely MCV1 at 9 months (ARD = 18%, 95%CI: 7%, 28%) and MCV2 coverage (ARD = 17%, 95%CI: 1%, 34%) rose significantly, and wastage fell (ARD = -7%, 95%CI: -14%, -1%). By endline, 29% of 5-dose health workers opened vials ≥10 times monthly (none in control); caregivers in both intervention groups reported 11% fewer measles-related MOVs. A nationwide 5-dose switch was estimated to save 17% in procurement cost per fully vaccinated (two-dose) child. CONCLUSIONS: The combined 5-dose intervention improved MCV1 timeliness and MCV2 coverage and reduced wastage, addressing a key operational barrier and potentially supporting measles elimination in Ethiopia.

Humans↗

PubMed2026

Stroke risk following BNT162b2 vaccination: a systematic review and meta-analysis of self-controlled case series studies.

INTRODUCTION: Whether BNT162b2 (Pfizer-BioNTech) vaccination increases stroke risk remains a public health concern. This is the first meta-analysis to synthesize self-controlled case series (SCCS)-derived stroke risk estimates specifically for BNT162b2 vaccination. METHODS: PubMed and Embase were searched from inception through 9 May 2026, following PRISMA 2020 guidelines. Eight eligible SCCS studies were pooled using a random-effects model with restricted maximum likelihood (REML) estimation and the Knapp-Hartung adjustment. RESULTS: Eight studies across six countries encompassing several million vaccinated individuals were included. The pooled incidence rate ratio (IRR) was 0.967 (95% CI 0.892-1.049; I2 = 69.2%), indicating no statistically significant increase in stroke risk. Subgroup analyses showed no evidence of effect modification across continent, risk-window length, dose category, SCCS variant, or age group. CONCLUSIONS: These findings provide no evidence of increased short-term stroke risk following BNT162b2 vaccination at the population level. The observed heterogeneity appeared to be partly driven by methodological differences rather than true biological variation in vaccine effect.

Humans↗

PubMed2025

Exploring determinants of vaccine hesitancy among healthcare professionals: a systematic literature review.

INTRODUCTION: This systematic review aims to assess determinants of vaccine hesitancy (VH) among healthcare professionals, to identify knowledge gaps and inform targeted training programs. RESEARCH DESIGN AND METHODS: A systematic search of PubMed and Scopus was conducted in February 2024. PRISMA criteria were applied, and methodological quality was assessed using a cross-sectional study evaluation tool. Studies addressing HCWs' VH determinants, including knowledge, attitudes, communication, and organizational factors, were included. RESULTS: Out of 1394 records, 221 articles were included. Reported prevalence of VH among HCWs varied across studies, reflecting differences in professional roles, settings, and vaccines studied. Key determinants included gaps in knowledge, personal beliefs, organizational barriers, and communication skills. The review highlights the importance of evidence-based information, continuing education, and effective communication in addressing VH among HCWs. CONCLUSIONS: Educational and organizational interventions are essential to improve HCWs' knowledge, attitudes, and practices regarding vaccination. Strengthening vaccine education, fostering effective communication, and addressing organizational challenges can reduce hesitancy and support HCWs in promoting vaccination among patients. Future initiatives should consider the diversity of educational settings, professional roles, and training requirements across healthcare systems.

Humans↗

PubMed2026

Approaches to observational study designs and analytical options to evaluate the safety of multi-dose vaccines: a systematic review.

INTRODUCTION: Observational studies require careful considerations when evaluating the safety of multidose vaccines. We reviewed design and analytical approaches in observational studies evaluating the safety of multidose vaccines in the post-licensure phase. METHODS: EMBASE, MEDLINE, Web of Science, and Scopus (2018-2022) were searched for hypothesis-testing studies evaluating the safety of multidose vaccines. Key features from frequently used designs were extracted. RESULTS: Among 123 eligible studies, cohort (46%) and self-controlled case series (SCCS)/self-controlled risk interval (SCRI) (40%) followed by case-control (12%) were the most common designs, and 15% of studies used multiple designs. Among cohort studies evaluating multiple doses, vaccination date (36%) and cohort entry with time-updated exposure status (32%) were frequent approaches used to define time zero. Twenty-eight percent of cohort studies did not report time zero; all but one evaluated COVID-19 vaccine effect on post-delivery and fertility-related outcomes. For SCCS/SCRI, 64% of studies accounted for event-dependent exposures, mainly by including pre-exposure periods (53%) and modified SCCS model (48%), while 20% employed multiple correction strategies. Among studies using multiple designs, 68% reached consistent conclusions. CONCLUSIONS: SCCS/SCRI and cohort designs dominate multidose vaccine safety studies. Clear reporting on time zero in pregnancy and fertility-related cohort studies, and on addressing event-dependent exposures in SCCS/SCRI studies is needed, along with guidance on interpreting results from multiple designs.

Humans↗

PubMed2026

Comparison of immunogenicity, safety, and efficacy of EVA71 vaccine in children: a systematic review and meta-analysis.

INTRODUCTION: Enterovirus 71 (EV-A71) is a principal cause of hand, foot, and mouth disease (HFMD), potentially leading to severe neurological complications in children. Inactivated EV-A71 vaccines have been introduced. This study compares the immunogenicity, safety, and efficacy of EV-A71 vaccines versus placebo in pediatric populations. RESEARCH DESIGN AND METHODS: Following a PROSPERO-registered protocol, RCTs involving EV-A71 in children were identified via PubMed, Scopus, Cochrane, and ClinicalTrials.gov. Two independent reviewers performed screening, extraction, and RoB assessments (RoB 2.0). RESULTS: Five phase III RCTs involving 36,659 children were included. EV-A71 vaccination significantly increased seropositivity across follow-up periods, including early (RR 5.8), medium-term (RR 3.09), and long-term (RR 2.95) response. Seroconversion was significantly higher in the vaccinated group (pooled RR 13.04, 95% CI 2.80-60.61; p < 0.001). Geometric mean titers, analyzed using the ratio of means approach, were significantly higher in the vaccinated group during early and medium-term follow-up. Vaccine efficacy against EV-A71-associated HFMD exceeded 98% (pooled RR 0.02, 95% CI 0.01-0.09; p = 0.0028; I2 = 50%). Solicited local and systemic adverse events were mild and comparable between groups. CONCLUSION: Inactivated EV-A71 vaccines robust immunogenicity, high clinical efficacy, and an acceptable safety profile in children. Future studies should explore long-term protection, booster schedules, and multivalent formulations against non-EV-A71 serotypes.

Humans↗

PubMed2026

A multi-center, open-labelled, randomized controlled extended phase III non-inferiority clinical trial to evaluate the immunogenicity and tolerability of poliomyelitis vaccine (Vero cells), inactivated, Sabin strains administered with or without routine infant vaccines.

BACKGROUND: Oral poliovirus vaccine (OPV) has been reported to cause vaccine-derived poliovirus and vaccine-associated paralytic poliomyelitis, and the limited global supply of conventional IPV has led many countries to rely on fractional-dose IPV regimens alongside OPV. The current study aims to assess the sIPV safety and immunogenicity when given concurrently with or in a staggered manner with routine immunization. METHODS: A multi-country, multi-center, open-label, randomized controlled, extended phase III non-inferiority clinical trial was conducted with 1442 healthy infants aged 6-8 weeks from Bangladesh and Pakistan enrolled and randomized into four groups, i.e., co-administration group 1 (group C1), co-administration group 2 (group C2), staggered administration group 1 (group S1) and staggered administration group 2 (group S2). Antibody levels were determined using the collected sera for immunogenicity evaluation. The difference in seroconversion rates between the coadministration group and the staggered administration group is compared using the Cochran-Mantel-Haenszel χ2 (CMH-χ2) test, stratified by study site. Non-inferiority is concluded if the lower bound of the 95% confidence interval (CI) for the rate difference (coadministration group minus staggered administration group) is greater than -10%. The trial was registered prior to patient enrollment at clinicaltrials.gov (NCT05850364), and the protocol and statistical analysis plan are available at https://clinicaltrials.gov/study/NCT05850364. The trial is closed to new participants. FINDINGS: The post-vaccination seroconversion rates for PV I were 90.3% (306/339) in group C1 and 87.0% (261/300) in group S1, for PV II, 91.7% (311/339) in group C1 and 91.3% (274/300) in group S1 and for PV III, 86.4% (293/339) in group C1 and 92.3% (277/300) in group S1. Among adverse reactions (ARs) reported within 7 days of vaccination, the incidence was similarly high in both the co-administration and staggered vaccination groups (92.8% vs. 95.5%). INTERPRETATION: Our results demonstrated favorable safety and immunogenicity of co-administration of sIPV with other routine infant vaccines according to a 3-dose primary immunization schedule.

Humans↗

PubMed2026

Do vaccinated cases transmit measles? A systematic review and meta-analysis.

INTRODUCTION: We reviewed evidence on whether vaccinated individuals can transmit measles and conducted a meta-analysis to understand transmission characteristics. METHODS: We searched and extracted data from peer-reviewed and gray literature and included studies reporting measles transmission events from vaccinated individuals. We meta-analyzed the data to calculate the median number of transmissions from vaccinated cases by measles burden, number of doses, and time since first and last dose. RESULTS: We identified 11,911 peer-reviewed and 22 gray literature records and included 33 articles in our review. Seventy individuals who had received 1 or more doses of measles-containing vaccine transmitted measles virus, resulting in 237 secondary cases. Vaccinated transmitters in eliminated areas were older (median age of 19 years (IQR: 3, 21)) than those in non-eliminated areas (median age 16 years; IQR 13, 18) (p = 0.12). Additionally, 91% (30/33) of studies provided data on subsequent transmission generations, leading to 812 measles cases traced back to vaccinated individuals, with a median of 4 (IQR: 1, 10) cases per vaccinated transmitter. CONCLUSION: Measles transmissions from vaccinated cases, although relatively uncommon, must be considered in public health investigations, as such transmissions can contribute to outbreaks.

Adolescent↗

PubMed2026

Immunogenicity and safety of prophylactic HPV vaccines in people living with HIV: A systematic review and meta-analysis.

Human papillomavirus (HPV) is a major global public health concern, causing genital warts and cancers of the cervix, anus, oropharynx, vulva, and penis. People living with HIV (PLWH) face a disproportionately elevated burden of HPV infection and HPV-related malignancies due to chronic immunosuppression. We conducted a systematic review and meta-analysis searching six databases from January 2006 to June 2026 without language restrictions. Twenty-five studies were included in the systematic review; 12 independent studies (N = 1,493 for HPV16) were included in the quantitative meta-analysis. Using a DerSimonian-Laird random-effects model with logit transformation, pooled seroconversion rates were: HPV16 97.8% (95% CI: 94.9-99.1%; I2 = 89.6%; 15 datasets), HPV18 94.2% (95% CI: 86.1-97.7%; I2 = 95.8%; 13 datasets), HPV6 97.0% (95% CI: 93.7-98.6%; I2 = 66.1%; 10 studies), and HPV11 97.1% (95% CI: 90.5-99.1%; I2 = 95.5%; 10 studies). CD4 count was the most consistently reported modifier of immunogenic response: HPV16 seroconversion was 98.5% in PLWH with CD4 > 350 cells/μL vs. 71.1% in those with CD4 ≤ 200 cells/μL (ACTG A5240). All three vaccine generations demonstrated high immunogenicity. Two doses of the nonavalent vaccine were non-inferior to three doses in virologically suppressed women (Papillon RCT). No vaccine-related serious adverse events were reported. GRADE certainty of evidence was moderate for HPV16, HPV6, and HPV11, and low for HPV18. Prophylactic HPV vaccination achieves high seroconversion rates across all vaccine generations in PLWH. CD4 count significantly modifies vaccine response, underscoring the importance of vaccination before severe immunosuppression develops. These findings support current international recommendations advocating HPV vaccination for all PLWH.

Humans↗