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The Oxford Vaccine Group are inviting students in school year 12 to take part in a research project to understand whether immunising teenagers with vaccines against ‘Meningitis B’ could protect them and the rest of the community against these potentially deadly bacteria. This is a national study involving 24 000 year 12 students across the United Kingdom. Teenagers at participating schools are being asked to take part by local research teams involved.
The safety and immunogenicity of a bivalent conjugate vaccine against Salmonella enterica Typhi and Paratyphi A in healthy Indian adults: a phase 1, randomised, active-controlled, double-blind trial.
BACKGROUND: Enteric fever caused by Salmonella enterica Typhi and Salmonella Paratyphi A is an important public health problem, especially in low-income and middle-income countries with limited access to safe water and sanitation. We present results from, to our knowledge, the first ever human study of a bivalent paratyphoid A-typhoid conjugate vaccine (Sii-PTCV). METHODS: In this double-blind phase 1 study, 60 healthy Indian adults were randomly assigned (1:1) to receive a single intramuscular dose of either Sii-PTCV or typhoid conjugate vaccine (Typbar-TCV). Safety was assessed by observing solicited adverse events for 1 week, unsolicited events for 1 month, and serious adverse events (SAEs) over 6 months. Immunogenicity at 1 month and 6 months was assessed by measuring anti-capsular polysaccharide antigen Vi (anti-Vi) IgG and IgA against Salmonella Typhi and anti-lipopolysaccharide (LPS) IgG against Salmonella Paratyphi A by ELISA, and functional antibodies using serum bactericidal assay (SBA) against Salmonella Paratyphi A. This study is registered with Clinical Trial Registry-India (CTRI/2022/06/043608) and is completed. FINDINGS: 60 participants were enrolled. Of these 60 participants, 57 (95%) participants were male and three (5%) participants were female. Solicited adverse events were observed in 27 (90%) of 30 participants who received Sii-PTCV and 26 (87%) of 30 participants who received Typbar-TCV. The most common local solicited event was pain in 27 (90%) participants who received Sii-PTCV and in 23 (77%) participants who received Typbar-TCV. The most common solicited systemic event was myalgia in five (17%) participants who received Sii-PTCV, whereas four (13%) participants who received Typbar-TCV had myalgia and four (13%) had headache. No vaccine-related unsolicited adverse events or SAEs were reported. The seroconversion rates on day 29 were 96·7% (95% CI 82·8-99·9) with Sii-PTCV and 100·0% (88·4-100·0) with Typbar-TCV for anti-Vi IgG; 93·3% (77·9-99·2) with Sii-PTCV and 100·0% (88·4-100·0) with Typbar-TCV for anti-Vi IgA; 100·0% (88·4-100·0) with Sii-PTCV and 3·3% (0·1-17·2) with Typbar-TCV for anti-LPS (paratyphoid); and 93·3% (77·9-99·2) with Sii-PTCV and 0% (0·0-11·6) with Typbar-TCV for SBA titres (paratyphoid). Paratyphoid anti-LPS immune responses were sustained at day 181. INTERPRETATION: Sii-PTCV was safe and immunogenic for both typhoid and paratyphoid antigens indicating its potential for providing comprehensive protection against enteric fever. FUNDING: Serum Institute of India.
Development of methodology to support molecular endotype discovery from synovial fluid of individuals with knee osteoarthritis: The STEpUP OA consortium.
OBJECTIVES: To develop a protocol for largescale analysis of synovial fluid proteins, for the identification of biological networks associated with subtypes of osteoarthritis. METHODS: Synovial Fluid To detect molecular Endotypes by Unbiased Proteomics in Osteoarthritis (STEpUP OA) is an international consortium utilising clinical data (capturing pain, radiographic severity and demographic features) and knee synovial fluid from 17 participating cohorts. 1746 samples from 1650 individuals comprising OA, joint injury, healthy and inflammatory arthritis controls, divided into discovery (n = 1045) and replication (n = 701) datasets, were analysed by SomaScan Discovery Plex V4.1 (>7000 SOMAmers/proteins). An optimised approach to standardisation was developed. Technical confounders and batch-effects were identified and adjusted for. Poorly performing SOMAmers and samples were excluded. Variance in the data was determined by principal component (PC) analysis. RESULTS: A synovial fluid standardised protocol was optimised that had good reliability (<20% co-efficient of variation for >80% of SOMAmers in pooled samples) and overall good correlation with immunoassay. 1720 samples and >6290 SOMAmers met inclusion criteria. 48% of data variance (PC1) was strongly correlated with individual SOMAmer signal intensities, particularly with low abundance proteins (median correlation coefficient 0.70), and was enriched for nuclear and non-secreted proteins. We concluded that this component was predominantly intracellular proteins, and could be adjusted for using an 'intracellular protein score' (IPS). PC2 (7% variance) was attributable to processing batch and was batch-corrected by ComBat. Lesser effects were attributed to other technical confounders. Data visualisation revealed clustering of injury and OA cases in overlapping but distinguishable areas of high-dimensional proteomic space. CONCLUSIONS: We have developed a robust method for analysing synovial fluid protein, creating a molecular and clinical dataset of unprecedented scale to explore potential patient subtypes and the molecular pathogenesis of OA. Such methodology underpins the development of new approaches to tackle this disease which remains a huge societal challenge.
The Effect of Acute Knee Injuries and Related Knee Surgery on Serum Levels of Pro- and Anti-inflammatory Lipid Mediators and Their Associations With Knee Symptoms.
BACKGROUND: Despite an acute knee injury being a major risk factor for osteoarthritis, the factors that initiate and maintain this risk of longer-term knee symptoms are poorly understood. Bioactive lipids derived from omega-3 and -6 polyunsaturated fatty acids have key roles in the regulation of the inflammatory response and have been linked to joint damage and osteoarthritis pain in translational models. HYPOTHESIS: There would be associations between systemic levels of bioactive lipids and knee symptoms longitudinally after an acute knee injury and related knee surgery. STUDY DESIGN: Controlled laboratory study. METHODS: This study analyzed a subset of young, active adults who had sustained an acute knee injury (recruited via a surgical care pathway) and healthy age- and sex-matched controls. Surgery, if performed, was conducted after the baseline serum sample was taken and before the 3-month and 2-year visits. Liquid chromatography-tandem mass spectrometry of 41 bioactive lipids was carried out in sera of (1) 47 injured participants (median age, 28 years) collected at baseline (median, 24 days after injury), 3 months, and 2 years, along with the Knee injury and Osteoarthritis Outcome Score, and (2) age- and sex-matched controls. RESULTS: Levels of the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (P≤ .0001) and docosahexaenoic acid (P≤ .0001) and the pro-resolving lipid mediators 17- and 14-hydroxydocosahexaenoic acid, and 18-hydroxyeicosapentaenoic acid were all significantly greater at baseline in injured participants compared with the later time points and also higher than in healthy controls (P = .0019 and P≤ .0001, respectively). Levels of pro-inflammatory prostaglandins E2 and D2, leukotriene B4, and thromboxane B2 were significantly lower at baseline compared with the later time points. Higher levels of 8,9-, 11,12-, and 14,15-dihydroxyeicosatrienoic acid (DHET) were cross-sectionally associated with more severe knee pain/symptoms according to the Knee injury and Osteoarthritis Outcome Score at 2 years (P = .0004, R2 = 0.251; P = .0002, R2 = 0.278; and P = .0012, R2 = 0.214, respectively). CONCLUSION: The profile of pro-resolving versus pro-inflammatory lipids at baseline suggests an initial activation of pro-resolution pathways, followed by the later activation of pro-inflammatory pathways. CLINICAL RELEVANCE: In this largely surgically managed cohort, the association of soluble epoxide hydrolase metabolites, the DHETs, with more severe knee symptoms at 2 years provides a rationale for further investigation into the role of this pathway in persisting knee symptoms in this population, including potential therapeutic strategies.
Oral Swab Testing With Xpert MTB/RIF Ultra for the Diagnosis of Tuberculosis in Children Aged <5 Years in Uganda: An Exploratory Interim Analysis of Diagnostic Accuracy in the NOD-pedFEND Cohort.
BACKGROUND: Obtaining respiratory samples to diagnose tuberculosis in young children is challenging. Oral swabs are alternative noninvasive specimens for microbiology. METHODS: We conducted an interim prospective diagnostic accuracy evaluation of Xpert MTB/RIF Ultra (Ultra) on oral swabs for pulmonary tuberculosis in children aged <5 years in Uganda. Most children had 2 consecutive swabs collected in a single cryovial (double swabs). Reference tests consisted of Ultra and culture on 2 nasopharyngeal aspirates and 1 gastric aspirate and Ultra on 1 stool. Children were classified as having confirmed tuberculosis, unconfirmed tuberculosis, or unlikely tuberculosis per the National Institutes of Health. Diagnostic accuracy was determined against a microbiological reference standard and a composite reference standard. RESULTS: From August 2021 to February 2024, 444 children were enrolled, of whom 399 had complete classifications: 33 had confirmed tuberculosis, 269 had unconfirmed tuberculosis, 70 had unlikely tuberculosis, and 27 were unclassifiable. The median age was 16 months and 17% had HIV. Most children (398/399) had oral swabs collected, all with conclusive Ultra results. The sensitivity of double swabs was 6.9% with a microbiological reference standard (95% CI, 1.9%-22.0%) and 1.8% with a composite reference standard (95% CI, .8%-4.1%). Specificity was at least 99%. Swabs detected tuberculosis in 4 children with negative reference test results, of whom 3 had unconfirmed tuberculosis. CONCLUSIONS: The low sensitivity of Ultra on double swabs precludes its role as a principal diagnostic approach in young children. However, detection of tuberculosis in children who were not otherwise microbiologically diagnosed suggests the utility of oral swabs as add-on samples to increase yield.
A phase 1/2a clinical trial to assess safety and immunogenicity of an adenoviral-vectored capsular group B meningococcal vaccine
Capsular group B meningococcus (MenB) remains an important cause of disease globally, and additional vaccines against MenB would aid in reducing the incidence of infection. Previous work has demonstrated that a MenB adenoviral-vectored vaccine, ChAdOx1 MenB.1, elicited high serum bactericidal responses in preclinical models after a single dose, supporting further clinical development of this vaccine. Here, we report the results of a trial designed to assess the safety and immunogenicity of ChAdOx1 MenB.1 in healthy adults aged 18 to 50. In this phase 1/2a, single-center trial, participants received one or two doses of ChAdOx1 MenB.1 at days 0 and 180. One dose of ChAdOx1 MenB.1 was also given at day 180 to some individuals primed with one dose of 4CMenB at day 0. Participants recorded their symptoms in an electronic diary after vaccination, and safety blood readouts were monitored. Serum bactericidal antibody (SBA) assays were performed against a panel of MenB target strains. ChAdOx1 MenB.1 was well tolerated with no safety concerns and elicited protective SBA titers against a MenB strain expressing a homologous factor H–binding protein (fHbp) variant in 100% of participants after two doses. However, cross-reactivity analysis indicated a low SBA response to strains expressing heterologous fHbp, suggesting that a multivalent vaccine may be needed. In sum, ChAdOx1 MenB.1 is immunogenic in humans, and addition of another fHbp variant or of another antigen in this platform could provide an approach to extend protection against endemic MenB disease.
Consultation report - considerations for a regulatory pathway for bivalent Salmonella Typhi/Paratyphi A vaccines for use in endemic countries.
Enteric fever caused by Salmonella enterica serovars Typhi and Paratyphi A and, to a lesser extent, S. Paratyphi B and C, remains a significant cause of mortality and morbidity in resource-constrained settings. Typhoid conjugate vaccines (TCVs) protect against S. Typhi but no vaccine to date protects against paratyphoid fever. There are several bivalent S. Typhi/Paratyphi A products in development; however, the low incidence of paratyphoid fever in many settings limits the feasibility of phase 3 efficacy studies. Two bivalent vaccines adding the S. Paratyphi A-specific O:2 lipopolysaccharide conjugated to a protein carrier to TCV constructs have successfully completed phase 1 studies and will progress rapidly in their development. The WHO's Product Development for Vaccines Advisory Committee (PDVAC) endorsed a regulatory pathway for a bivalent S. Typhi/Paratyphi A vaccine that contemplates demonstrating protective efficacy against S. Paratyphi A infection in a controlled human infection model (CHIM). Since the use of CHIM data in lieu of phase 3 efficacy studies and to identify markers of immune protection is not yet widely accepted by regulatory bodies, the WHO organized a consultation with vaccine developers, manufacturers, and regulators. The purpose of the meeting was to discuss the feasibility and considerations for the licensure of a bivalent S. Typhi/Paratyphi A vaccine. The aim of the consultation was to gain alignment among key stakeholders and facilitate the pathway to licensure in endemic countries.
Prevalence, clinical management, and outcomes of adults hospitalised with endemic arbovirus illness in southeast Europe (MERMAIDS-ARBO): a prospective observational study.
BACKGROUND: Arboviruses have expanded into new regions in Europe, yet data indicate gaps in disease notifications and a risk of further spread. We aimed to report on prevalence, clinical management, and outcomes of endemic arbovirus infections in southeast Europe. METHODS: In this prospective observational study (MERMAIDS-ARBO), we enrolled adults (age ≥18 years) hospitalised with an arbovirus-compatible disease syndrome within 21 days of symptom onset across 21 hospitals in seven countries in southeast Europe over four arbovirus seasons (May 1-Oct 31, during 2016-19). We obtained data from case report forms completed by site investigators on admission and discharge. Participants were excluded if they had non-infectious CNS disorders, symptoms of another confirmed cause, an identified focal source of infection, or symptoms caused by recurrence of a pre-existing condition. The primary outcome was the proportion of participants with confirmed or probable acute infections with West Nile virus (WNV), tick-borne encephalitis virus (TBEV), Crimean-Congo haemorrhagic fever virus (CCHFV), or Toscana virus (TOSV), per reference laboratory criteria. Secondary outcomes were the proportions of patients treated with antivirals, antibiotics, or corticosteroids; the proportion of patients requiring intensive care; hospital length of stay; and mortality. FINDINGS: Of 2896 adults screened for eligibility, 929 were recruited and 913 met protocol-defined eligibility criteria (median age 43·1 years [IQR 29·5-59·7]; 550 [60%] men, 361 [40%] women, and two [<1%] with missing data). 530 (58%) participants presented with suspected meningitis, encephalitis, or both, and 318 (35%) with fever plus myalgia, fever plus arthralgia, or both. 820 (90%) reported no international travel within 21 days before symptom onset. 727 (80%) were administered antibiotics, 379 (42%) corticosteroids, and 222 (24%) antivirals. The median length of hospital stay was 9 days (IQR 6-14), and 113 (12%) required intensive care. Of 847 participants with a reference laboratory sample who met full eligibility criteria for analysis, 110 (13%) were diagnosed with 114 confirmed or probable acute arbovirus infections (four had coinfections or cross-reactivity): one (<1%) with CCHFV, 16 (2%) with TBEV, 44 (5%) with TOSV, and 53 (6%) with WNV. There was one death (<1%) of an individual with WNV. Of the 110 participants, 49 (45%) had a local clinician-attributed arbovirus discharge diagnosis. INTERPRETATION: Our data highlight the need to strengthen arbovirus surveillance systems for the early detection of emerging and re-emerging outbreaks, including investments to increase awareness of arbovirus infections among clinicians, to improve access to specialist diagnostics, and to develop effective and accessible vaccines and treatments to protect populations and health systems in southeast Europe. FUNDING: European Commission and Versatile Emerging infectious disease Observatory. TRANSLATIONS: For the Greek, Albanian, Romanian, Bosnian, Serbian, and Croatian translation of the summary see Supplementary Materials section.
Multi-antigen serology and a diagnostic algorithm for the detection of arbovirus infections as novel tools for arbovirus preparedness in southeast Europe (MERMAIDS-ARBO): a prospective observational study.
BACKGROUND: Arboviruses are increasingly affecting Europe, partly due to the effects of climate change. This increase in range and impact emphasises the need to improve preparedness for emerging arboviral infections that often co-circulate and might have overlapping clinical syndromes. We aimed to strengthen surveillance networks for four clinically relevant arboviruses in southeast Europe. METHODS: This study reports an in-depth analysis of the MERMAIDS-ARBO prospective observational study in adults (ie, aged ≥18 years) hospitalised with an arbovirus-compatible disease syndrome in 21 hospitals in seven countries in southeast Europe over four arbovirus seasons (May 1-Oct 31, 2016-19) to obtain arbovirus prevalence outcomes. The main objectives of the MERMAIDS-ARBO study, describing the clinical management and outcomes of four arboviruses endemic to southeast Europe, including Crimean-Congo haemorrhagic fever virus (CCHFV), tick-borne encephalitis virus (TBEV), Toscana virus, and West Nile virus (WNV), are reported elsewhere. In this analysis, given the challenges associated with arbovirus diagnostics, we developed a diagnostic algorithm accounting for serology outcomes and sample timing to study arbovirus prevalence in southeast Europe. Serum samples were collected on days 0, 7, 28, and 60 after hospital admission and tested for anti-CCHFV IgG and IgM antibodies with ELISAs (confirmed with an indirect immunofluorescence test) and for IgG and IgM antibodies specific to TBEV, Toscana virus, and WNV with custom-printed protein microarrays (confirmed with virus neutralisation tests). All acute-phase samples were tested by PCR for all four viruses. Descriptive analyses were performed for virus-reactive cases by geography and year, and possible factors (eg, age, sex, and insect bites) associated with virus reactivity were assessed. FINDINGS: Of 2896 individuals screened, 913 were eligible for inclusion, of whom 863 (514 men, 332 women, and 17 unknown) had samples sent to the study reference laboratories and were included in molecular and serological analyses. Some individuals had insufficient clinical data to be included in the clinical analysis, but met the eligibility criteria for and were included here. Serum sampling was incomplete (eg, samples missing from one or more timepoints or no data on time since symptom onset) for 602 (70%) patients, and the timing of collection was often heterogeneous after symptom onset up to 40 days (average median delay of 5-6 days across all timepoints), affecting the ability to diagnose arbovirus infection by serology. By use of an interpretation table incorporating timing and completeness of sampling, one (<1%) participant had a confirmed recent infection with CCHFV, ten (1%) with TBEV, 40 (5%) with Toscana virus, and 52 (6%) with WNV. Most acute confirmed infections of Toscana virus were found in Albania (25 [63%] of 40), whereas WNV was primarily identified in Romania (36 [69%] of 52). Albania also had the highest overall Toscana virus seropositivity (168 [60%] of 282), mainly explained by patients confirmed to be exposed or previously exposed (104 [62%] of 168). Patients without antibodies to WNV or Toscana virus were significantly younger than patients with antibodies (mean difference -8·48 years [95% CI -12·31 to -4·64] for WNV, and -6·97 years [-9·59 to -4·35] for Toscana virus). We found higher odds of Toscana virus reactivity in men (odds ratio 1·56 [95% CI 1·15 to 2·11]; p=0·0055), WNV reactivity with mosquito bites versus no mosquito bites (2·47 [1·54 to 3·97]; p=0·0002), and TBEV reactivity with tick bites versus no tick bites (2·21 [1·19 to 4·11]; p=0·018). INTERPRETATION: This study shows that despite incomplete and heterogeneous data, differential diagnosis of suspected arbovirus infections is possible, and the diagnostic interpretation algorithm we propose could potentially be used to strengthen routine diagnostics in clinical settings in areas at risk for arboviral diseases. Our data highlight potential hotspots for arbovirus surveillance and risk factors associated with these particular arbovirus infections. FUNDING: European Commission and Versatile Emerging infectious disease Observatory. TRANSLATIONS: For the Greek, Albanian, Romanian, Bosnian, Serbian, and Croatian translation of the summary see Supplementary Materials section.
Risk analysis for outpatient experimental infection as a pathway for affordable RSV vaccine development
Controlled human infection models (CHIMs) are an important tool for accelerating clinical development of vaccines. CHIM costs are driven by quarantine facilities but may be reduced by performing CHIM in the outpatient setting. Furthermore, outpatient CHIMs offer benefits beyond costs, such as a participant-friendly approach and increased real-world aspect. We analyze safety, logistic and ethical risks of respiratory syncytial virus (RSV) CHIM in the outpatient setting. A review of the literature identified outpatient CHIMs involving respiratory pathogens. RSV transmission risk was assessed using data from our inpatient and outpatient RSV CHIMs (EudraCT 020-004137-21). Fifty-nine outpatient CHIMs using RSV, Streptococcus pneumoniae, rhinovirus, and an ongoing Bordetella Pertussis outpatient CHIM were included. One transmission event was recorded. In an inpatient RSV CHIM, standard droplet and isolation measures were sufficient to limit RSV transmission and no symptomatic third-party transmission was measured in the first outpatient RSV CHIM. Logistic and ethical advantages support outpatient CHIM adoption. We propose a framework for outpatient RSV CHIM with risk mitigation strategies to enhance affordable vaccine development.
5-year vaccine protection following a single dose of Vi-tetanus toxoid conjugate vaccine in Bangladeshi children (TyVOID): a cluster randomised trial.
BACKGROUND: WHO currently recommends a single dose of typhoid conjugate vaccine (TCV) in high-burden countries based on 2-year vaccine efficacy data from large randomised controlled trials. Given the decay of immunogenicity, the protection beyond 2 years is unknown. We therefore extended the follow-up of the TyVAC trial in Bangladesh to assess waning of vaccine protection to 5 years after vaccination. METHODS: We conducted a cluster randomised controlled trial (TyVAC; ISRCTN11643110) in Dhaka, Bangladesh, between 2018 and 2021. Children aged 9 months to 15 years were invited to receive a single dose of TCV or Japanese encephalitis vaccine between April 15, 2018, and November 16, 2019, based on the randomisation of their clusters of residence. Children who received the Japanese encephalitis vaccine were invited to receive TCV at the final visit between Jan 6, and Aug 31, 2021, according to the protocol. This follow-on study extended the follow-up of the original trial until Aug 14, 2023. The primary endpoint of this study was to compare the incidence of blood culture-confirmed typhoid between children who received TCV in 2018-19 (the previous-TCV group) and those who received the vaccine in 2021 (the recent-TCV group), to evaluate the relative decline in vaccine protection. We also did a nested study using the test-negative design comparing the recent-TCV and previous-TCV groups with unvaccinated individuals, as well as an immunogenicity study in a subset of 1500 children. FINDINGS: Compared with the recent-TCV group, the previous-TCV group had an increased risk of typhoid fever between 2021-23, with an adjusted incidence rate ratio of 3·10 (95% CI 1·53 to 6·29; p<0·0001), indicating a decline in the protection of a single-dose of TCV 3-5 years after vaccination. The extrapolated vaccine effectiveness in years 3-5 was 50% (95% CI -13 to 78), and was validated using the test-negative design analysis, with a vaccine effectiveness of 84% (74 to 90) in the recent-TCV group and 55% (36 to 68) in the previous-TCV group, compared with unvaccinated individuals. Anti-Vi-IgG responses declined over the study period. The highest rate of decay was seen in children vaccinated at younger than 2 years in the original trial. The inverse correlation between age and the decay of antibodies was also seen in the subgroup analysis of vaccine effectiveness, where the youngest age group (<7 years at fever visits) exhibited the fastest waning, with vaccine effectiveness dropping to 24% (95% CI -29 to 55) at 3-5 years after vaccination. INTERPRETATION: A decline in the protection conferred by a single-dose TCV was observed 3-5 years after vaccination, with the greatest decline in protection and immune responses observed in children vaccinated at younger ages. A booster dose of TCV around school entry age might be needed for children vaccinated while younger than 2 years to sustain protection against typhoid fever during the school years when the risk is the highest. FUNDING: The Bill & Melinda Gates Foundation.
The validity of test-negative design for assessment of typhoid conjugate vaccine protection: comparison of estimates by different study designs using data from a cluster-randomised controlled trial.
BACKGROUND: Typhoid fever remains a substantial public health challenge in low-income and middle-income countries. By 2023, typhoid conjugate vaccines (TCVs) had been introduced in six countries globally, with more than 50 million doses distributed. Now that TCVs are being deployed, there is a need for observational studies to assess vaccine effectiveness in the field. We aimed to evaluate the validity of different observational study designs in estimating vaccine protection. METHODS: We compared different observational and experimental study designs for assessing vaccine effectiveness by re-analysing data from the TyVAC Bangladesh trial, a participant-blinded and observer-blinded cluster-randomised controlled trial done in Mirpur, Dhaka, Bangladesh. 150 geographical clusters were randomly assigned (1:1) to receive either TCV or Japanese encephalitis vaccine. Eligible children aged 9 months to 15 years were offered a single dose of the vaccine randomly assigned to their cluster of residence, and baseline vaccination was done between April 15 and May 15, 2018. We compared estimates of vaccine effectiveness from the cluster-randomised controlled trial analysis-which assessed the risk of blood-culture-confirmed typhoid fever among recipients of TCV versus recipients of Japanese encephalitis vaccine-with estimates from cohort study and test-negative case-control study design (TND) analyses, which compared recipients of TCV with non-vaccinees in the 75 geographical clusters where TCV was administered. We further conducted negative-control exposure (NCE) and negative-control outcome (NCO) analyses as bias indicators. FINDINGS: 41 344 (67%) of 62 025 age-eligible children in the study area received the TCV or Japanese encephalitis vaccine during the baseline vaccination campaign. Among the 62 025 age-eligible children, 5582 blood-culture specimens were collected by passive surveillance, including 2546 (46%) specimens from the 75 TCV clusters. The estimated vaccine efficacy was 89% (95% CI 81-93) in the cluster-randomised controlled trial analysis, 79% (70-86) by the cohort design, 88% (79-93) by the TND when pan-negatives were used as test-negative controls, and 90% (75-96) by the TND when specimens positive for pathogens other than Salmonella enterica serotype Typhi were used as test-negative controls. Using NCE analysis, Japanese encephalitis vaccination was associated with an increased risk of typhoid fever compared with non-vaccinees in the 75 Japanese encephalitis clusters in the cohort design (incidence rate ratio 1·98 [95% CI 1·56-2·52]), but no significant association between Japanese encephalitis vaccination and typhoid fever was found with the TND. Similarly, an increased risk of non-typhoid infections was observed in the cohort NCO analyses when comparing vaccinees with non-vaccinees in both Japanese encephalitis vaccine clusters and TCV clusters, but not in the TND NCO analyses. INTERPRETATION: Our findings suggests that the TND provides reliable estimates of TCV effectiveness, whereas the cohort design can bias vaccine effectiveness estimates, possibly due to unmeasured confounding effects, such as health-care-seeking behaviours. NCE and NCO approaches are useful tools for identifying such biases. FUNDING: The Bill & Melinda Gates Foundation.
A systems biology approach to define SARS-CoV-2 correlates of protection.
Correlates of protection (CoPs) for SARS-CoV-2 have yet to be sufficiently defined. This study uses the machine learning platform, SIMON, to accurately predict the immunological parameters that reduced clinical pathology or viral load following SARS-CoV-2 challenge in a cohort of 90 non-human primates. We found that anti-SARS-CoV-2 spike antibody and neutralising antibody titres were the best predictors of clinical protection and low viral load in the lung. Since antibodies to SARS-CoV-2 spike showed the greatest association with clinical protection and reduced viral load, we next used SIMON to investigate the immunological features that predict high antibody titres. It was found that a pre-immunisation response to seasonal beta-HCoVs and a high frequency of peripheral intermediate and non-classical monocytes predicted low SARS-CoV-2 spike IgG titres. In contrast, an elevated T cell response as measured by IFNγ ELISpot predicted high IgG titres. Additional predictors of clinical protection and low SARS-CoV-2 burden included a high abundance of peripheral T cells. In contrast, increased numbers of intermediate monocytes predicted clinical pathology and high viral burden in the throat. We also conclude that an immunisation strategy that minimises pathology post-challenge did not necessarily mediate viral control. This would be an important finding to take forward into the development of future vaccines aimed at limiting the transmission of SARS-CoV-2. These results contribute to SARS-CoV-2 CoP definition and shed light on the factors influencing the success of SARS-CoV-2 vaccination.
Re-imagining combination vaccines for travel medicine
With the increasing number of innovative vaccines, combination vaccines are becoming essential. For travellers, they provide streamlined protection against multiple infectious diseases, reducing healthcare visits. However, challenges remain in demonstrating the appeal of the traveller vaccine market and meeting development requirements to ensure high quality, safety and performance.
The effect of pertussis vaccination in pregnancy on the immunogenicity of acellular or whole-cell pertussis vaccination in Gambian infants (GaPS): a single-centre, randomised, controlled, double-blind, phase 4 trial.
BACKGROUND: Vaccinating women against pertussis in pregnancy protects young infants from severe disease and death. Vaccination-induced maternally derived antibodies, however, might subsequently modulate (and specifically blunt) the infant's serological response to their primary series of pertussis vaccinations. We examined the effect of pertussis immunisation in pregnancy on the immunogenicity of primary acellular or whole-cell pertussis vaccines in a west African cohort. METHODS: GaPs was a randomised, controlled, double-blind, phase 4 trial conducted in The Gambia. We used a predefined block randomisation scheme to randomly assign healthy, HIV-negative, pregnant participants (1:1) to receive a pertussis-containing (tetanus-diphtheria-acellular pertussis-inactivated polio virus [Tdap-IPV]) or tetanus-toxoid only vaccine at 28-34 weeks' gestation. At the same time, their infants were randomly assigned (1:1) to receive diphtheria-tetanus-acellular pertussis (DTaP) or diphtheria-tetanus-whole-cell pertussis (DTwP) primary vaccine at 8, 12, and 16 weeks postnatally. Participants and trial staff were masked to the allocation of the maternal vaccine. The field team and participants became unmasked to the allocation of the infant vaccine at 16 weeks; laboratory staff and all other investigators remained masked to infant vaccine allocation until the end of the trial. The primary outcome was geometric mean concentration (GMC) of infant pertussis toxin-specific antibodies at 20 weeks and 9 months postnatally and was assessed in infants who received all three doses of the primary vaccine. Secondary outcomes included memory B-cell responses, and exploratory outcomes were total pertussis-specific antibody binding concentrations and functional antibody titres (pertussis toxin-specific neutralising activity [PTNA] and serum bactericidal activity [SBA]). Vaccine reactogenicity was assessed in mothers and infants for 3 days after each vaccine dose. Pregnant women had an extra safety visit 7 days after vaccination. The study is registered with ClinicalTrials.gov, NCT03606096. FINDINGS: Between Feb 13, 2019, and May 17, 2021, we enrolled 343 maternal-infant pairs. 239 (77%) infants were included in the per-protocol immunogenicity analysis. Among infants of mothers receiving Tdap-IPV in pregnancy, at 20 weeks postnatally, the GMCs of anti-pertussis toxin IgG were more than three-fold lower in infants vaccinated with three doses of DTwP (n=64) than in infants vaccinated with three doses of DTaP (n=53; adjusted geometric mean ratio 0·28, 98·75% CI 0·16-0·50). This difference persisted up to 9 months (0·31, 0·17-0·55). Conversely, among infants born to tetanus toxoid-immunised mothers, post-vaccination GMCs of anti-pertussis toxin IgG at 9 months were higher in those vaccinated with DTwP (n=58) than in those vaccinated with DTaP (n=64; 2·02, 1·15-3·55). Tdap-IPV immunisation in pregnancy blunted anti-pertussis toxin IgG following primary vaccination in all infants but particularly in those receiving DTwP, with GMCs of anti-pertussis toxin IgG more than eight-fold lower in DTwP-vaccinated infants born to Tdap-IPV-vaccinated mothers than in DTwP-vaccinated infants born to tetanus toxoid-immunised mothers (0·12, 98·75% CI 0·07-0·22 at 20 weeks; 0·07, 0·03-0·17 at 9 months). Similarly, DTwP-vaccinated infants born to Tdap-IPV-vaccinated mothers also showed significant blunting of PTNA, SBA, total pertussis-specific antibody binding, and memory B-cell responses after primary immunisation, whereas minimal blunting was observed among DTaP-vaccinated infants. However, the absolute levels of these responses generated by DTwP-vaccinated infants remained similar to or, in many cases, were higher than those generated by DTaP-vaccinated infants. There was no difference in reactogenicity between the two maternal vaccines, with most reactions graded 0 or 1. There were no serious adverse events related to vaccination or trial participation. INTERPRETATION: Vaccinating women with Tdap-IPV in pregnancy was safe and well tolerated in a sub-Saharan African setting and boosted the quantity and quality of pertussis-specific antibodies in infants in early life. Although Tdap-IPV was associated with relative blunting of the immune response to the DTwP primary vaccination series, pertussis-specific antibody quality and memory B-cell responses were nevertheless preserved, regardless of the vaccine given during pregnancy. FUNDING: GaPs was conducted as part of the Pertussis Correlates Of Protection Europe (PERISCOPE) consortium, which received funding from the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement 115910. This Joint Undertaking receives support from the EU's Horizon 2020 research and innovation programme, the European Federation of Pharmaceutical Industries and Associations, and the Bill & Melinda Gates Foundation.
CMV serostatus is associated with improved survival and delayed toxicity onset following anti-PD-1 checkpoint blockade
Abstract Cytomegalovirus (CMV) is a globally endemic latent herpes virus that profoundly impacts T cell immunity. We investigated the oncological consequences of CMV infection across 341 prospectively recruited patients receiving immune checkpoint blockade (ICB) for melanoma. CMV+ patients with metastatic melanoma (MM) have higher lymphocyte counts, reduced neutrophil to lymphocyte ratio and divergent CD8+ T cell gene expression. Combination anti-CTLA-4/anti-PD-1 ICB, but not single-agent anti-PD-1 ICB, induces cytotoxicity and CMV-associated gene expression in CD8+ T cells from CMV− patients. Correspondingly, overall survival was independent of CMV serostatus in combination anti-CTLA-4/anti-PD-1 ICB recipients (CMV+ hazard ratio for death: 1.02, P = 0.92), whereas CMV+ single-agent anti-PD-1 ICB recipients had improved overall survival (CMV+ hazard ratio for death: 0.37, P < 0.01), a finding also seen in CMV+ adjuvant single-agent anti-PD-1 ICB recipients (CMV+ hazard ratio for recurrence: 0.19, P = 0.03). We identify TBX21, encoding T-bet, as a transcriptional driver of CMV-associated CD8+ T cell gene expression, finding that TBX21 expression is predictive of overall survival (hazard ratio: 0.62, P = 0.026). CMV+ patients unexpectedly show reduced cumulative incidence of grade 3+ immune-related adverse events at 6 months (0.30 versus 0.52, P = 2.2 × 10−5), with lower incidence of colitis (P = 7.8 × 10−4) and pneumonitis (P = 0.028), an effect replicated in non-melanoma ICB recipients (n = 58, P = 0.044). Finally, we find reduced CMV seropositivity rates in patients with MM compared with UK Biobank controls (odds ratio: 0.52, P = 1.8 × 10−4), indicating CMV seropositivity may protect against MM. Specifically, patients with BRAF-mutated MM are less likely to be CMV+ (odds ratio = 2.2, P = 0.0054), while CMV− patients present 9 yr earlier with BRAF wild-type MM (P = 1.3 × 10−4). This work reveals an interaction between CMV infection, MM development according to BRAF status and response to ICB, while demonstrating CMV infection is protective against severe ICB immune-related adverse events, highlighting the potential importance of previous infection history and chronic immune activation in MM development and immunotherapy outcomes.