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Objectives: To describe and quantify the maternal and neonatal factors associated with Group B streptococcus (GBS) disease in infants <90 days of age. Setting: Neonatal Units in London, Oxford, Portsmouth and Bristol. Patients: Cases were infants <90 days of age with invasive GBS disease diagnosed between 2000 and 2003, and controls were healthy infants born in the same hospital and in the same birth weight category. Main Outcome Measures: Demographic and clinical data on the mother, baby, birth and neonatal stay. Results: 138 cases and 305 controls were recruited. The majority of cases (74%) presented in the first week of life (early onset, EO); most on day 1 (89%). 65% of EO cases had one or more clinical risk factors (prematurity, prolonged rupture of membranes (PROM), known maternal GBS carriage, fever during labour). A multivariable logistic regression analysis found that the strongest independent associations with GBS disease were known maternal carriage of GBS (odds ratio (OR) 6.9), maternal infection in the peripartum period (OR 4.2) and maximum temperature in labour (OR 2.2 per degrees C). GBS disease was associated with twice the likelihood of PROM and fetal tachycardia (p = 0.05 and 0.07 respectively). EO cases had lower Apgar scores and were more likely to have respiratory distress and convulsions, and to require tube feeding than controls. They spent longer in hospital than controls, requiring longer stays at all levels of care. Conclusions: Independent of birth weight, a number of maternal, birth and neonatal factors are significantly associated with GBS disease. The management of babies with GBS disease results in an appreciable use of hospital resources. [ABSTRACT FROM AUTHOR]

Objectives: To assess the persistence of serum Haemophilus influenzae type b antibodies and the prevalence of H influenzae type b carriage in a group of preschool age children previously vaccinated in infancy.Design: Names were randomly selected from immunisation records. Families were visited on five occasions over a period of 12 months and throat swabs were taken from all family members present, with blood obtained from children at the first and last visits.Results: One hundred and fifty three children at a median age of 3.6 years had a geometric mean titre (GMT) of 1.06 micrograms/ml (95% CI 0.80 to 1.38). Eight per cent had an undetectable antibody concentration, received a booster dose of plain PRP vaccine, and responded with concentrations > 2 micrograms/ml. GMT at 4.5 years of age was 0.89 microgram/ml (0.69 to 1.16). Twelve children who had been exposed to H influenzae had a GMT of 4.7 v 0.8 micrograms/ml for those without exposure.Conclusions: Accelerated immunisation against H influenzae without a second year booster results in persistence of satisfactory serum concentrations of antibody to 4.5 years of age. In those with undetectable antibody, immunological memory may still be present. [ABSTRACT FROM AUTHOR]

Objective: To compare immunological responses of preterm infants to a four-component meningococcal B vaccine (4CMenB; Bexsero) following a 2+1 vs a 3+1 schedule, and to describe reactogenicity of routine vaccines., Design: An open-label, phase IV randomised study conducted across six UK sites., Setting: Neonatal units, postnatal wards, community recruitment following discharge., Participants: 129 preterm infants born at a gestation of <35 weeks (64 in group 1 (2+1), 65 in group 2 (3+1)) were included in the analysis. Analysis was completed for postprimary samples from 125 participants (59 in group 1, 66 in group 2) and for postbooster samples from 118 participants (59 in both groups)., Interventions: Infants randomised to 4CMenB according to a 2+1 or a 3+1 schedule, alongside routine vaccines., Main Outcome Measures: Serum bactericidal antibody (SBA) assays performed at 5, 12 and 13 months of age: geometric mean titres (GMTs) and proportions of infants achieving titres ≥4 compared between groups., Results: There were no significant differences in SBA GMTs between infants receiving a 2+1 compared with a 3+1 schedule following primary or booster vaccination, but a significantly higher proportion of infants had an SBA titre ≥4 against strain NZ98/254 (porin A) at 1 month after primary vaccination using a 3+1 compared with a 2+1 schedule (3+1: 87% (95% CI 76 to 94%), 2+1: 70% (95% CI 56 to 81%), p=0.03).At 12 weeks of age those in the 3+1 group, who received a dose of 4CMenB, had significantly more episodes of fever >38.0°C than those in the 2+1 group who did not (group 2+1: 2% (n=1); 3+1: 14% (n=9); p=0.02)., Conclusions: Both schedules were immunogenic in preterm infants, although a lower response against strain NZ98/254 was seen in the 2+1 schedule; ongoing disease surveillance is important in understanding the clinical significance of this difference., Trial Registration Number: NCT03125616., Competing Interests: Competing interests: JL and RB perform contract research on behalf of UKHSA for GlaxoSmithKline (GSK), Pfizer and Sanofi. JC works for an institution which conducts meningococcal vaccine research on behalf of GSK; he receives no personal payment or inducement of any kind. MS was an employee of the University of Oxford and Oxford University Hospitals Foundation NHS trust up until September 2022, and in this role acted as an investigator for clinical research studies funded or otherwise supported by the vaccine manufacturers GSK, Janssen, AstraZeneca, Pfizer, Novavax and MCM vaccines. He received no personal financial benefit for this work. As of September 2022, MS has been an employee of Moderna UK and holds equity in this company; however, all study activities and data analysis were completed before this date., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Congenital human cytomegalovirus (CMV) infection is the most common congenital infection, affecting around 1 in 200 infants in high-income settings. It can have life-long consequences for up to one in four children, including sensorineural hearing loss and neurodisability. Despite the frequency of congenital CMV and the severity for some children, it is a little-known condition by pregnant women, families and healthcare providers. Timely diagnosis of CMV infection in pregnancy is important to facilitate consideration of treatment with valaciclovir, which may reduce the risk of transmission to the fetus or reduce the severity of the outcomes for infected infants. Recognition of features of congenital CMV is important for neonatologists, paediatricians and audiologists to prompt testing for congenital CMV within the first 21 days of life. Early diagnosis gives the opportunity for valganciclovir treatment, where appropriate, to improve outcomes for affected infants. Further research is urgently needed to inform decisions about antenatal and neonatal screening, long-term outcomes for asymptomatic and symptomatic infants, predictors of these outcomes and optimal treatment for women and infants., Competing Interests: Competing interests: Provided consultancy and /or investigator roles in relation to product development for MSD (AK, CEJ, PTH, SBD), Sanofi Pasteur (AK, CEJ, PTH, SBD), Gilead (AB), Janssen (PTH), AstraZeneca (PTH), Moderna (CEJ, PTH, SBD) Pfizer (CEJ, PTH), Valneva (PTH) on behalf of their institutions. Chair of CCMVNet (provider of European Registry for Congenital CMV infection) (HL). Co-chair of the European Congenital CMV Initiative (ECCI) (CEJ)., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To compare the occurrence of chickenpox in children with cancer who received varicella immunoglobulin (VZIG) or aciclovir as postexposure prophylaxis (PEP)., Design: Prospective multicentre service evaluation of children with cancer who received either VZIG or aciclovir as PEP following significant exposure to varicella zoster virus (VZV) over a 24-month period from May 2018., Setting: Data were collected from 9 UK Paediatric Oncology Primary Treatment Centres., Patients: Children under 16 years old with a diagnosis of cancer and/or previous haematopoietic stem cell transplant who were VZV seronegative at exposure and/or diagnosis and received PEP following significant VZV exposure., Main Outcome Measures: The primary outcome was the incidence of breakthrough varicella within 6 weeks of VZV exposure and treatment with PEP., Results: A total of 105 eligible patients were registered with a median age of 4.9 years (range 1.1-10.5 years). Underlying diagnoses were acute leukaemia (64), solid tumours (22), Langerhans cell histiocytosis (9), central nervous system (CNS) tumours (8) and other (2). Aciclovir was received by 86 patients (81.9%), 18 received VZIG (17.1%) and 1 valaciclovir (0.9%). There were seven reported break-through VZV infections in 103 patients at follow-up (7/103, 6.8%). Clinical VZV developed in 5/84 of the aciclovir group (6.0%, 95% CI 2.0 to 13.3) and 2/18 of VZIG group (11.1%, 95% CI 1.4 to 34.7). All breakthrough infections were either mild (5/7) or moderate (2/7) in severity., Conclusion: Aciclovir is a safe and effective alternative to VZIG as VZV PEP in children with cancer and should be considered as standard of care., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: To describe the epidemiology, age at infection, clinical characteristics and outcome of listeria infection in young infants to inform management and empiric antibiotic choice in young infants., Design: Prospective 2-year surveillance of Listeria monocytogenes infection in young infants detected through the British Paediatric Surveillance Unit 'orange card' system and triangulated with the public health laboratories., Setting: National population study (England, Wales, Scotland and the Ireland) PATIENTS: All infants under 90 days with proven or probable invasive listeriosis MAIN OUTCOME MEASURES: Incidence, mortality, age of infection, clinical characteristics and outcome RESULTS: During a 2-year period (2017-2019), 27 cases of listeriosis in infants <90 days of age were reported. The incidence of listeriosis in this study was 1.8 per 100 000 live births with 7% mortality (2/27). Nearly all cases presented within the first 24 hours of life (26/27). The majority (20/27, 74%) were born preterm and 16/24 (67%) were born to women from ethnic minority backgrounds., Conclusions: Invasive listeriosis in young infants in the UK and Ireland is rare and presents early in the neonatal period. National guidelines that recommend the use of amoxicillin as part of empiric regimes for sepsis and meningitis in infants over 1 month of age should be modified., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To gain an understanding of the variation in available resources and clinical practices between neonatal units (NNUs) in the low-income and middle-income country (LMIC) setting to inform the design of an observational study on the burden of unit-level antimicrobial resistance (AMR)., Design: A web-based survey using a REDCap database was circulated to NNUs participating in the Neonatal AMR research network. The survey included questions about NNU funding structure, size, admission rates, access to supportive therapies, empirical antimicrobial guidelines and period prevalence of neonatal blood culture isolates and their resistance patterns., Setting: 39 NNUs from 12 countries., Patients: Any neonate admitted to one of the participating NNUs., Interventions: This was an observational cohort study., Results: The number of live births per unit ranged from 513 to 27 700 over the 12-month study period, with the number of neonatal cots ranging from 12 to 110. The proportion of preterm admissions <32 weeks ranged from 0% to 19%, and the majority of units (26/39, 66%) use Essential Medicines List 'Access' antimicrobials as their first-line treatment in neonatal sepsis. Cephalosporin resistance rates in Gram-negative isolates ranged from 26% to 84%, and carbapenem resistance rates ranged from 0% to 81%. Glycopeptide resistance rates among Gram-positive isolates ranged from 0% to 45%., Conclusion: AMR is already a significant issue in NNUs worldwide. The apparent burden of AMR in a given NNU in the LMIC setting can be influenced by a range of factors which will vary substantially between NNUs. These variations must be considered when designing interventions to improve neonatal mortality globally., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To determine the likely rate of patient randomisation and to facilitate sample size calculation for a full-scale phase III trial of varicella zoster immunoglobulin (VZIG) and aciclovir as postexposure prophylaxis against chickenpox in children with cancer., Design: Multicentre pilot randomised controlled trial of VZIG and oral aciclovir., Setting: England, UK., Patients: Children under 16 years of age with a diagnosis of cancer: currently or within 6 months of receiving cancer treatment and with negative varicella zoster virus (VZV) serostatus at diagnosis or within the last 3 months., Interventions: Study participants who have a significant VZV exposure were randomised to receive PEP in the form of VZIG or aciclovir after the exposure., Main Outcome Measures: Number of patients registered and randomised within 12 months of the trial opening to recruitment and incidence of breakthrough varicella., Results: The study opened in six sites over a 13-month period. 482 patients were screened for eligibility, 32 patients were registered and 3 patients were randomised following VZV exposure. All three were randomised to receive aciclovir and there were no cases of breakthrough varicella., Conclusions: Given the limited recruitment to the PEPtalk2 pilot, it is unlikely that the necessary sample size would be achievable using this strategy in a full-scale trial. The study identified factors that could be used to modify the design of a definitive trial but other options for defining the best means to protect such children against VZV should be explored., Trial Registration Number: ISRCTN48257441, EudraCT number: 2013-001332-22, sponsor: University of Birmingham., Competing Interests: Competing interests: None declared, (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2019. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: To quantify delays during management of children with suspected meningitis., Design: Multicentre prospective cohort study., Setting: Three UK tertiary paediatric centres; June 2011-June 2012 PATIENTS: 388 children aged <16 years hospitalised with suspected meningitis or undergoing lumbar puncture (LP) during sepsis evaluation., Main Outcome Measures: Time of prehospital and in-hospital assessments, LP, antibiotic treatment and discharge; types of prehospital medical assessment and microbiological results. Data collected from hospital records and parental interview., Results: 220/388 (57%) children were seen by a medical professional prehospitalisation (143 by a general practitioner). Median times from initial hospital assessment to LP and antibiotic administration were 4.8 hours and 3.1 hours, respectively; 62% of children had their LP after antibiotic treatment. Median time to LP was shorter for children aged <3 months (3.0 hours) than those aged 3-23 months (6.2 hours, P<0.001) or age ≥2 years (20.3 hours, P<0.001). In meningitis of unknown cause, cerebrospinal fluid (CSF) PCR was performed for meningococcus in 7%, pneumococcus in 10% and enterovirus in 76%. When no pathogen was identified, hospital stay was longer if LP was performed after antibiotics (median 12.5 days vs 5.0 days, P=0.037)., Conclusions: Most children had LP after antibiotics were administered, reducing yield from CSF culture, and PCRs were underused despite national recommendations. These deficiencies reduce the ability to exclude bacterial meningitis, increasing unnecessary hospital stay and antibiotic treatment., Competing Interests: Competing interests: SK has received support to attend scientific meetings from GlaxoSmithKline. DFK has received research funding from GlaxoSmithKline and received support from GlaxoSmithKline and Sanofi-Pasteur to attend scientific meetings. PTH received a grant from Pfizer towards the submitted work. He is also an investigator for clinical trials done on behalf of St George’s, University of London, UK, sponsored by vaccine manufacturers and has been a consultant to Novartis and Pfizer on Group B Streptococcus vaccines, but received no payments for this. SN has acted as a consultant to Novartis Vaccines on serogroup B meningococcal vaccine and has received honoraria from Novartis and Pfizer for consultancy work paid into an educational and administrative fund. MS has received grants from Pfizer outside of the submitted work. AJP has received grants from Novartis, Pfizer and Okairos, outside of the submitted work. His department received unrestricted educational grants from Pfizer, GSK and Astra Zeneca in July 2016 for a course on Infection and Immunity in Children. AJP has previously conducted clinical trials of meningococcal meningitis vaccines on behalf of the University of Oxford, funded by vaccine manufacturers, but no longer does so and he received no personal payments from them. AJP is chair of the UK Department of Health’s Joint Committee on Vaccines and Immunisation, chair of the European Medicine Agency’s Scientific Advisory Group on Vaccines and a member of the WHO’s SAGE. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health, the EMA, or the WHO., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Bacterial conjugate vaccines have dramatically changed the epidemiology of childhood meningitis; viral causes are increasingly predominant, but the current UK epidemiology is unknown. This prospective study recruited children under 16 years of age admitted to 3 UK hospitals with suspected meningitis. 70/388 children had meningitis-13 bacterial, 26 viral and 29 with no pathogen identified. Group B Streptococcus was the most common bacterial pathogen. Infants under 3 months of age with bacterial meningitis were more likely to have a reduced Glasgow Coma Score and respiratory distress than those with viral meningitis or other infections. There were no discriminatory clinical features in older children. Cerebrospinal fluid (CSF) white blood cell count and plasma C-reactive protein at all ages, and CSF protein in infants <3 months of age, distinguished between bacterial meningitis and viral meningitis or other infections. Improved diagnosis of non-bacterial meningitis is urgently needed to reduce antibiotic use and hospital stay., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Unlabelled: Anaphylaxis is a rare adverse event following immunisation (AEFI) and unlikely to be detected in prelicensure vaccine trials. Previous retrospective studies have been hampered by the paucity of information available to passive reporting schemes. The aim of the present study was to estimate the incidence and clinical presentation of anaphylaxis as an AEFI using prospective active surveillance., Methods: Children under 16 in the UK and Ireland with suspected anaphylaxis as an AEFI were reported through the British Paediatric Surveillance Unit (BPSU) between September 2008 and October 2009. Paediatricians completed questionnaires on presentation, diagnosis, management and outcome., Results: A total of 7 out of 15 reports met criteria for anaphylaxis following immunisation. Four of the seven children reacted more than 30 min after administration of the vaccine. Six children required treatment with intramuscular adrenaline and intravenous fluids, but all made a full recovery. Denominators were not available for all vaccines so an overall incidence was not calculated, however the estimated incidence was 12.0 per 100,000 dose for single component measles vaccine and 1.4 cases per million doses for the bivalent human papilloma virus vaccine (Cervarix, GSK)., Conclusions: Anaphylaxis remains a rare adverse event following immunisation. No cases were related to vaccines given as part of the 'routine' infant and preschool immunisation programme, despite over 5.5 million vaccines being delivered in this time period. Some children had delayed onset of symptoms and this should be considered when vaccinating those at higher risk of anaphylaxis.

Children treated for acute leukaemia are at increased risk of infection with Streptococcus pneumoniae. The basis for this may include low levels of pneumococcal antibody but this has not been well studied. The authors measured serotype-specific pneumococcal IgG antibody concentrations in children treated for acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML) ≥6 months after completion of standard-dose chemotherapy. Pneumococcal serotype-specific IgG antibody concentrations were low. None of the subjects had protective concentrations against all the heptavalent-pneumococcal conjugate vaccine serotypes. There was no significant difference in antibody concentrations between subjects with ALL and AML (p≥0.05). Children treated for ALL and AML generally have non-protective antibody concentrations against S pneumoniae. There is significant morbidity associated with pneumococcal disease in this patient group and strategies for vaccination are required.

Objectives: To describe postexposure prophylaxis (PEP) against varicella zoster virus (VZV) in children being treated for malignancy in the UK and Ireland: the population at risk, frequency of exposure, clinical practice and attitudes among healthcare providers., Design: An observational study in three parts: (1) a retrospective survey of serostatus at diagnosis of malignancy, (2) collation of varicella zoster immune globulin (VZIG) dispensing data over a 3-year period and (3) an online survey of paediatric oncologists' clinical practice and beliefs in relation to VZV disease and its prevention., Setting: UK and Ireland., Participants: Children diagnosed with malignancy in 2009 (serostatus survey) or receiving VZIG between April 2006 and March 2009 (VZIG dispensing study). Paediatric oncologists and haematologists working in tertiary paediatric oncology centres and related shared care units in the UK and Ireland (physician survey)., Results: Of 1500 children diagnosed with malignancy each year, at least 24% are VZV seronegative. Few centres make efforts to prevent household exposure by vaccinating VZV-susceptible family members. Exposures to VZV result in the administration of PEP to approximately 250 children with cancer annually: half receive an intramuscular injection of VZIG while the remainder receive a course of oral aciclovir. The choice of PEP is made by doctors. There is no consensus among paediatric oncologists as to which is the better option, reflecting the lack of a secure evidence base., Conclusions: A randomised controlled trial to compare the effectiveness and acceptability of VZIG and aciclovir as PEP against varicella is both desirable and feasible.

Aims: To estimate the annual incidence of hospitalisations due to severe complications of varicella, describe the complications and estimate annual mortality., Methods: Active surveillance throughout the UK and Ireland for 13 months by paediatricians notifying cases to the British Paediatric Surveillance Unit and completing a questionnaire. The case definition was any child aged <16 years hospitalised with complicated varicella, as defined by a list of conditions, or admitted to ICU/HDU with varicella., Results: 188 cases were notified for the surveillance period, of which 112 (0.82/100 000 children/year) met the case definition and were not duplicates. Confirmed cases had a median age of 3 years (range 0-14). The complications were: bacteraemia/septic shock (n = 30), pneumonia (n = 30), encephalitis (n = 26), ataxia (n = 25), toxic shock syndrome/toxin-mediated disease (n = 14), necrotising fasciitis (n = 7), purpura fulminans/disseminated coagulopathy (n = 5), fulminant varicella (n = 5) and neonatal varicella (n = 3). 52 children (46%) had additional bacterial infections. Six deaths were due, or possibly due, to varicella, including one intrauterine death. Four of the other five children who died (ages 2-14 years) had a pre-existing medical condition. Sequelae on discharge were reported for 41 cases (40%), most frequently ataxia or skin scarring. The median length of hospital stay was 7 days (range 1-68)., Conclusions: This study provides a minimum estimate of severe complications and death resulting from varicella in children in the UK and Ireland. Most complications, excluding deaths, occur in otherwise healthy children and thus would be preventable only through a universal childhood immunisation programme.

Objective: To estimate the prevalence of nasopharyngeal (NP) carriage of pneumococcus (Streptococcus pneumoniae) and describe the antibiotic resistance patterns and serotypes in young children attending group day care in London., Design and Subjects: Cross-sectional survey of attendees at a sample of registered child day care centres (CDCCs) in a London borough., Setting: Urban setting with a socially and culturally diverse population., Methods and Outcomes: 19 CDCCs (13% of total) participated between March and November 2003. A single NP swab was required from each child, and parents completed a questionnaire about their child's health and attendance at day care. WHO methodology for pneumococcal carriage studies was followed., Results: 30% of parents consented. 234 swabs were collected from children aged 6 months to 5 years. 53% were boys and 81% were white. 120 children (51%, 95% CI 45% to 58%) carried pneumococci in their nasopharynx. None of the isolates were resistant to penicillin (upper CL 3%). 21 isolates were resistant to erythromycin (17.5%, 95% CI 11% to 25.5%). 68 isolates (57%) were serotypes included in the 7-valent conjugate vaccine. Non-white children had a lower prevalence of carriage (27% vs 58%)., Conclusion: The prevalence of pneumococcal NP carriage was high. The penicillin resistance rate is lower than in many other countries and may reflect a decrease in community antibiotic prescribing in the UK. Monitoring circulating serotypes is important in the context of recent changes to the vaccination policy. Further study is required to explore the association with ethnicity and risk factors for antibiotic resistance.

Premature infants are at increased risk of vaccine preventable infections, but audits have shown that their vaccinations are often delayed. Early protection is desirable. While the evidence base for immunisation of preterm infants is limited, the available data support early immunisation without correction for gestational age. For a number of antigens the antibody response to initial doses may be lower than that of term infants, but protective concentrations are often achieved and memory successfully induced. A 2-3-4 month schedule may be preferable for immunisation of preterm infants in order to achieve protection as early as possible, but an additional dose may be required to achieve persistence of protection. This update focuses on the use of routine childhood vaccines in premature infants.

Aims: To document the immunogenicity and persistence of antibody to polyribosyl-ribitol phosphate (PRP) as well as the clinical protection against invasive Haemophilus influenzae type b (Hib) disease in premature infants immunised at the routine schedule., Methods: Blood was obtained at 2, 5, 12, and 64 months of age from a cohort of prematurely born infants (

Haemophilus influenzae type b (Hib) is an important pathogen in children <5 years of age. The Hib conjugate vaccines were the first polysaccharide-protein conjugate vaccines to be used in routine childhood schedules. Their introduction in the UK in 1992 has resulted in the near elimination of Hib disease. The UK Hib vaccine programme has a number of unique features including an accelerated schedule, absence of a booster dose, and the inclusion of a catch up component at the beginning of the programme. Collaboration between UK paediatricians, microbiologists, and public health physicians has allowed active national surveillance of Haemophilus influenzae disease and enabled important conclusions to be drawn. These include high vaccine effectiveness, the presence of herd immunity, and the frequency of risk factors in cases of vaccine failure and in cases of invasive disease due to non-b H influenzae. Parallel studies have shown the immunogenicity, induction of immunological memory, and persistence of immunity following vaccination at the UK schedule, as well as measuring the impact of vaccination on pharyngeal Hib carriage. Cases continue to occur and complacency is ill advised, particularly as other vaccines and combinations are introduced. Surveillance of H influenzae disease in the UK remains important.