Prevention and Control of Haemophilus influenzae Type B Disease: Recommendations of the Advisory Committee on Immunization Practices (ACIP)

Objectives

The recommendations provide a comprehensive United States framework for preventing and controlling invasive Haemophilus influenzae type b (Hib) disease. They consolidate existing Advisory Committee on Immunization Practices (ACIP) guidance for clinicians, public-health officials, vaccination providers and immunisation programme staff, rather than introducing new recommendations.[1][2]The central objective is to sustain high uptake of the infant primary Hib vaccine series and booster doses, prevent disease among unimmunised and underimmunised children, and provide additional protection for people at increased clinical risk.[3][4]

• Provide routine Hib conjugate vaccination from age 2 months, using product-specific primary schedules and a booster dose at 12–15 months to maintain protective immunity.[4][5]
• Apply catch-up vaccination for children aged 12–59 months according to age at presentation and previous Hib doses.[4][6]
• Prioritise protection for infants too young to complete vaccination, children who have not completed primary or booster doses, and people with conditions associated with increased risk of invasive Hib disease.[7]
• Protect high-risk populations, including people with anatomic or functional asplenia, human immunodeficiency virus infection, immunoglobulin or early complement deficiencies, cancer treatment, and haematopoietic stem-cell transplantation.[1][6]
• Prioritise early protection of American Indian and Alaska Native infants, for whom Hib meningitis occurs earlier than in other United States infant populations; use a primary series containing polyribosylribitol phosphate oligosaccharide, or PRP-OMP, where indicated.[8][9]
• Provide revaccination or primary vaccination for children younger than 24 months who develop invasive Hib disease, because natural infection may not reliably produce protective antibody levels.[8]
• Prevent secondary transmission through appropriate antimicrobial chemoprophylaxis for eligible household and child-care contacts.[3]
• Support the Healthy People 2020 target of reducing annual Hib incidence among children aged under 5 years to 0.27 cases per 100,000 population.[10]

Hib vaccines protect against type b strains only; no vaccine is identified for non-type b or non-typeable H. influenzae.[7]Combination products may also protect against hepatitis B, diphtheria, tetanus, pertussis, poliomyelitis or meningococcal disease, depending on the product.[11]Sustained vaccination coverage is emphasised because Hib disease has become rare following vaccine introduction, but remains a risk among children who are unimmunised or underimmunised.[3]

Implementation

Implementation is based on ACIP recommendations, which provide external expert advice to the Director of the Centers for Disease Control and Prevention (CDC) on vaccine use for control of vaccine-preventable diseases in the United States civilian population.[12]Once adopted by the CDC Director and published in the Morbidity and Mortality Weekly Report, ACIP recommendations become CDC agency guidelines and are harmonised, where possible, with professional bodies such as the American Academy of Pediatrics and American Academy of Family Physicians.[12]The guidance combines routine immunisation, tailored vaccination for high-risk groups, disease surveillance, vaccine-safety monitoring and chemoprophylaxis.[2][3]

• Deliver licensed monovalent or combination Hib conjugate vaccines according to age and product schedule, including two primary doses at 2 and 4 months for PRP-OMP products and three doses at 2, 4 and 6 months for PRP-T products and relevant combination vaccines.[9]
• Provide booster vaccination generally at 12–15 months, at least eight weeks after the preceding Hib dose.[4]
• Allow concomitant administration with other routine childhood vaccines, as available evidence found no clinically significant immune interference.[5]
• Use monovalent Hib vaccines interchangeably for primary and booster doses; retain the same combination product where feasible, while accepting a valid dose from a different brand without repetition.[13]
• Vaccinate medically stable preterm infants from 2 months of chronological age using the routine infant schedule.[8][14]
• Provide three Hib doses to haematopoietic stem-cell transplant recipients, irrespective of prior Hib vaccination, starting 6–12 months after transplantation and separated by at least four weeks.[6][14]
• Time vaccination around immunosuppressive treatment, avoiding vaccination during chemotherapy or radiotherapy where response may be suboptimal and repeating relevant doses from at least three months after treatment.[14]
• Give Hib vaccine at least 14 days before elective splenectomy where feasible, and provide indicated doses to unimmunised asplenic children, adolescents and adults.[14][6]
• Use rifampin chemoprophylaxis for eligible contacts and certain index patients, while not requiring it after treatment with cefotaxime or ceftriaxone, which eradicate Hib colonisation.[3]
• Implement child-care prophylaxis when at least two invasive Hib cases occur within 60 days and unimmunised or underimmunised children attend.[3]

Evidence development involved the Hib Work Group, comprising academic clinicians, federal and state public-health professionals and representatives of professional medical organisations.[2]The work included teleconference and email consultation, review by ACIP, and subsequent CDC wording updates after ACIP approval on 20 February 2013.[10]The evidence base included published vaccine recommendations, the 2013 Infectious Diseases Society of America guideline for immunocompromised people, literature on immunogenicity, safety and effectiveness, and national surveillance findings.[2][10]

Operational monitoring uses Active Bacterial Core surveillance and the National Notifiable Diseases Surveillance System to track invasive Hib disease, including incidence among children aged under 5 years.[2][10]Complete serotyping is important to identify Hib cases and enable appropriate chemoprophylaxis.[3]Vaccine safety is monitored through the Vaccine Adverse Event Reporting System, jointly operated by CDC and the Food and Drug Administration, and the Vaccine Safety Datalink, a CDC collaboration with nine integrated healthcare organisations.[5]Report adverse events to the Vaccine Adverse Event Reporting System through online, facsimile or postal routes.[14][13]The source does not specify programme budgets, financing arrangements, a separate evaluation timetable, or a formal accountability framework beyond these surveillance and safety-monitoring mechanisms.[1][2]

Monitoring & Evaluation

Monitoring of Haemophilus influenzae type b (Hib) prevention combines invasive-disease surveillance, serotyping, vaccination-status analysis, vaccine-effectiveness research and post-licensure safety monitoring. The material does not set out a unified evaluation plan, reporting timetable, formal accountability framework or routine coverage-reporting system.[1][10][15][3]

• Monitor invasive Hib disease through the Active Bacterial Core surveillance system and the National Notifiable Diseases Surveillance System.[2]Use complete serotyping data to identify Hib cases and support appropriate chemoprophylaxis decisions.[3]
• Measure annual Hib incidence among children aged under five years against the Healthy People 2020 target of 0.27 cases per 100,000 population.[10]Incidence declined by 99% during 1989–2000 to fewer than one case per 100,000 children and remained below the target during 2000–2012.[1]
• Assess epidemiological inequities by population group. During 1998–2009, average annual Hib incidence among American Indian and Alaska Native children under five years was 1.3 per 100,000, compared with 0.16 per 100,000 among white children and 0.12 per 100,000 among black children.[7]
• Track Hib carriage prevalence as an epidemiological measure. Carriage declined from 2%–7% before vaccination to below 1% in the vaccine era.[1]
• Analyse surveillance records by vaccination status among children with invasive Hib disease. The cited analysis covered United States cases in children under five years during 2002–2012 and excluded 57 further children whose vaccination status was unknown.[16][15]
• Use vaccine immunogenicity, clinical safety and effectiveness studies to assess vaccine performance. Reported effectiveness included 93%–100% for a two-dose PedvaxHib series among Navajo infants and 95% in a prospective controlled United Kingdom trial of PRP-T vaccine.[5]
• Review evidence from product-specific and population studies to inform delivery decisions. In Alaska, statewide PRP-OMP use during 1991–1996 was associated with a reduction exceeding 90% in Hib disease rates among Alaska Native and non-native children.[8]Following replacement with a combination vaccine without an OMP Hib component, incidence among Alaska Native children increased from 19.8 to 91.1 cases per 100,000 children under five years, while rates among non-native children did not change.[8]After PRP-OMP-containing vaccines were reintroduced, incidence among Alaska Native children fell below six cases per 100,000 children under five years.[8]
• Monitor vaccine safety through the Vaccine Adverse Event Reporting System (VAERS), a national passive reporting system jointly operated by the Centers for Disease Control and Prevention and the Food and Drug Administration.[5]Report adverse events through VAERS online, by facsimile or by post.[14][13]
• Interpret VAERS findings as hypothesis-generating because reports can be affected by reporting bias and inconsistent data quality.[5]During 1990–2013, VAERS received 29,047 reports involving Hib-containing vaccines, approximately 17% of which were coded as serious, with no unusual or unexpected safety pattern identified.[17]
• Use the Vaccine Safety Datalink, a collaboration between the Centers for Disease Control and Prevention and nine integrated healthcare organisations, for population-based studies of safety hypotheses arising from research, reports, changes to immunisation schedules or new vaccines.[5]A cited study found an elevated risk of fever after DTaP-IPV-Hib vaccination among children aged one to two years but no association with other medically attended adverse health events.[17][18]
• Review medical records, death reports, adverse-event codes, relative risks and clinical diagnoses in post-licensure safety assessments.[17][18]A Comvax post-marketing evaluation found no consistent association between serious adverse events and vaccination.[18]
• Consider secondary-transmission data when determining chemoprophylaxis needs. Reported secondary attack rates were 2.1% among household contacts under 48 months, 6% among those under 12 months and 3% among those under 24 months.[3]Secondary cases were rare, risk was considered lower in child-care settings than in households, and secondary transmission of invasive non-type b disease had not been documented.[3]

Beyond disease incidence, carriage, vaccination status, serotyping, safety reports and cited effectiveness evidence, the source does not specify additional programme performance indicators, mandatory reporting processes, audit arrangements, evaluation frequency or institutional accountability mechanisms.[10][6][14][3]

Costing & Financing

No vaccine prices, programme budgets, budget allocations, financing arrangements, funding sources, resource-mobilisation measures, funding gaps or economic assumptions are specified in the supplied material.[12][1][10][16][17][6][3]

• Recognise that the material discusses licensed vaccines, vaccination schedules, safety surveillance and rifampin chemoprophylaxis without attaching costs or funding arrangements to these activities.[9][3]
• Note that the Morbidity and Mortality Weekly Report series is available electronically free of charge and that paper subscriptions are available through the United States Government Printing Office, but this does not constitute immunisation programme financing information.[19]
• Record no machine-readable cost items because no explicit monetary amount, currency, budget period, allocation or funding-gap value is provided.[20][21][22][23]