The Lancet Infectious Diseases

ObjectivesDespite the availability of effective vaccines, achieving the seroprevalence thresholds recommended by the World Health Organization (WHO) for eliminating measles, rubella, and mumps remains a public health challenge. MethodsA retrospective, cross-sectional serological survey was conducted, including 9,587 serum samples collected from 31 of the 32 federal entities of Mexico between September and December 2024. IgG antibody levels against measles, rubella, and mumps were quantified usi...

BackgroundThe SARS-CoV-2 LP.8.1 subvariant was incorporated into the 2025-2026 U.S. COVID-19 vaccines (mRNA-1273.251 and mRNA-1283.251). We evaluated immunogenicity and safety of these vaccines against vaccine-matched and emerging variants in individuals aged [≥]65 and those aged 12-64 years at high-risk of severe COVID-19. MethodsData were generated from: (1) two independent, ongoing, phase 3b/4, open-label, single-arm studies in which participants received a single dose of 50-{micro}g mRNA...

BackgroundAfrica continues to have a significant public health problem with mpox, where endemic transmission persists and overlaps with a high burden of other infectious diseases. Although their epidemiology and clinical impact are still poorly understood throughout the continent, coinfections with human immunodeficiency virus (HIV) and varicella-zoster virus (VZV) can affect the clinical picture, severity of the disease, and accuracy of the diagnosis. MethodsFollowing PRISMA criteria, we regis...

BackgroundHousehold contact investigation for tuberculosis (TB) is limited by referral for clinic-based testing services. We evaluated the performance of in-home tongue swab (TS) testing among symptom-agnostic household contacts (HHC) to inform HCI screening strategies. MethodsWe conducted a prospective cohort study among HHC of TB patients in Eastern Cape, South Africa. In-home testing of sputum and TSs, with TSs pooled from up to three HHCs, was performed using Xpert Ultra on portable GeneExp...

BACKGROUNDDiagnostic performance of tongue swab Mycobacterium tuberculosis PCR has been evaluated for facility-based triage of symptomatic tuberculosis (TB). It is unknown whether tongue swab performance differs for detection of asymptomatic TB in community-based screening. METHODSTongue swabs were collected from adult household contacts of TB patients (HHC Cohort), and symptomatic adults presenting to clinics with presumptive TB (Clinic Cohort), at eight South African sites. TB Cases were defi...

Infection with pnuemococcus bacteria is generally mild but can be more severe in the young and elderly, causing invasive pneumococcal disease (IPD) and community-acquired pneumonia (CAP). Although paediatric pneumococcal conjugate vaccine (PCV) programmes and elderly pneumococcal polysaccharide vaccine (PPV) programmes have reduced cases, we estimate that pneumococcal infection still leads to direct health care costs of around {pound}68M and approximately 16 thousand QALY losses in England per y...

BackgroundSevere Plasmodium falciparum malaria is a leading cause of death in sub-Saharan Africa, with most deaths occurring in children younger than five years of age. The RTS,S/AS01E (RTS,S) malaria vaccine delivered seasonally with Seasonal Malaria Chemoprevention (SMC) led to a two-third reduction in severe malaria and malaria deaths compared with either intervention given alone. The aim of this study was to assess the seasonal distribution and clinical presentation of children admitted in h...

The measles outbreak in Jalisco, Mexico (January-February 2026) experienced vigorous sustained transmission with an exponential growth rate = 0.10 (95% CI: 0.10-0.11) per day, doubling time = 6.3 days (95% CI: 6.3-6.9), yielding the effective reproduction number at 3.34 (95% CI: 3.16-3.54), with elevated incidence among infants and young adults.

The seasonal circulation of respiratory syncytial virus (RSV) in countries such as Japan, together with the transient nature of passive immunity conferred to infants via maternal vaccination or monoclonal antibody administration, may warrant a differential strategy for those born during the RSV inter-seasonal period. Maximal effectiveness may be achieved by deferring immunisation of this cohort from birth until entry into their first RSV season using catch-up administration of monoclonal antibod...

Persistent, asymptomatic Plasmodium infections are common in areas of high transmission due to acquired immunity. When asymptomatically infected individuals seek care for a fever caused by something other than malaria parasites, they may test positive for parasites and be incorrectly diagnosed as having clinical malaria. This study used distributions of qPCR parasite densities to estimate the fraction of fever attributable to malaria (malaria attributable fraction, MAF) in a cohort of 659 indivi...

BackgroundChikungunya virus (CHIKV) is an Aedes transmitted arbovirus. Demographic changes coupled with the expanding footprint of the mosquito from climate change have the potential to shift the global burden from the virus. MethodsHere we use projections of human demography and Aedes mosquitoes distribution to estimate baseline and future burden from CHIKV under different climate change scenarios in 178 countries. We then estimate the potential of vaccines to mitigate the growing burden. Fin...

COVID-19 remains a substantial public health challenge in the Netherlands. Next-generation COVID-19 vaccine, mRNA-1283, is approved in the European Union, with potential for higher relative vaccine efficacy compared with originally-licensed COVID-19 vaccines. Its potential public health and economic impact, in adults [≥]60 years and high-risk 18-59 years, was modelled versus no vaccination and originally-licensed mRNA-1273 and BNT162b2, adapting a published static Markov model with 1-year tim...

AO_SCPLOWBSTRACTC_SCPLOWInfluenza A subclade K viruses caused high infection rates in the 2025/2026 Northern Hemisphere season, raising concerns about antigenic drift and reduced vaccine effectiveness. We measured antibody responses in matched human pre- and post-vaccination sera against a vaccine-like as well as subclade K isolates. Pre-existing immunity to subclade K variants was noted with seasonal influenza vaccination boosting titers two-fold against subclade K and three-fold against the va...

BACKGROUND AND OBJECTIVESSeasonal influenza vaccination has been shown to reduce the risk of influenza and severe complications among children 6 months and older. Since 2010, reported numbers of influenza-associated pediatric deaths among children aged <18 years have ranged from 37 during the 2011-2012 season to 289 during 2024-2025. We estimated influenza vaccine effectiveness (VE) against pediatric death from 2016-2017 through 2024-2025. METHODSWe conducted a case-cohort analysis comparing cu...

Immune imprinting, also known as immune history, is a core aspect of adaptive immunity that influences antibody responses to future antigen exposures. Nevertheless, the impact of sequential flavivirus vaccinations on epitope targeting and antibody activity in humans remains incompletely understood. This question is particularly important in regions where the inactivated Japanese encephalitis virus (JEV) vaccines and the live-attenuated dengue virus (DENV) vaccines are used, as both have been ass...

We introduce PerTexP (Pertussis Time Exploration), an interactive modelling tool designed to investigate pertussis transmission dynamics and to support the evaluation of vaccination strategies and short-term projections. PerTexP allows users to explore and compare maternal, infant, and non-infant booster vaccination scenarios and to assess their potential impact on disease transmission, with a particular focus on the Italian epidemiological context. The tool is based on a discrete-time, stage-st...

BackgroundElimination of Plasmodium vivax is challenging due to its dormant liver stages (hypnozoites), which can reactivate weeks or months after the primary infection, causing relapses and ongoing transmission of the parasite. Despite these challenges, P. vivax clinical case numbers have declined over the past decade in Cambodia. We used parasite genotyping to assess whether the decline in case numbers was reflected in parasite diversity and relatedness as a proxy to transmission. MethodsGeno...

A number of vaccines and long-acting monoclonal antibodies have been shown to be effective in the prevention of respiratory syncytial virus (RSV) disease. However, an immune correlate of protection for RSV has not yet been identified. We conducted a systematic review to identify published reports of immunogenicity and/or efficacy in vaccines and long-acting monoclonal antibodies against RSV and performed a meta-analysis on extracted data to identify any relationship between antibody increase and...

BackgroundRoutine immunization (RI) is widely used to increase population immunity against measles. In low-resource settings, achieving immunity goals using RI alone has proved challenging and supplemental immunization activities (SIAs), large community-based vaccination campaigns conducted every few years, have been used to close immunity gaps. Although effective at covering the population unreached by RI and boosting the population immunity, SIAs are labor-intensive and expensive, allowing for...

BackgroundMalawi has one of the highest incidences and mortality due to cervical cancer, which is caused by the human papillomavirus (HPV). Achieving high HPV vaccination coverage is critical for advancing the World Health Organization (WHO) cervical cancer elimination strategy. This study aims to describe the spatio-temporal uptake of the first and second doses of the HPV vaccine in Malawi and to investigate the covariates associated with the uptake. MethodsWe analysed HPV vaccination coverage...