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Background Nirsevimab, a long‐acting monoclonal antibody, was shown to prevent respiratory syncytial virus (RSV) infections in newborns. We evaluated the cost‐effectiveness of nirsevimab strategies for newborns from the societal perspective in Hong Kong. Methods A Markov model was developed to simulate outcomes of four nirsevimab strategies in newborns: (1) year‐round, (2) seasonal, (3) catch‐up, and (4) no nirsevimab. Primary outcomes included RSV lower respiratory tract infections (LRTI) related events, direct and indirect costs, quality‐adjusted life year (QALY) loss, and incremental cost per QALY (ICER). Results In base‐case analysis, all strategies with nirsevimab reduced RSV–LRTI‐related events. The catch‐up group had the lowest QALY loss per 100,000 infants (38.82), followed by year‐round (45.71), seasonal (60.60), and no intervention groups (81.52). Three nirsevimab cost levels were examined: 10%, 25%, and 50% of the US cost. At 10% US cost (USD52), all strategies were cost‐saving versus no intervention. At 25% US cost (USD130), the ICER of the catch‐up group (vs. no intervention) was 141,925 USD/QALY. At 50% US cost (USD260), all nirsevimab strategies were not cost‐effective versus no intervention at a willingness‐to‐pay of 162,401 USD/QALY. Influential factors with thresholds were identified for RSV‐LRTI incidence, RSV‐related hospitalization and mortality, and nirsevimab effectiveness at the 25% US cost level (USD130). In probabilistic sensitivity analysis, the catch‐up and no intervention strategies were cost‐effective 100% of the time at 10% (USD52) and 50% (USD260) US cost, respectively. At 25% US cost (USD130), the catch‐up strategy was cost‐effective 58.56% of the time. Conclusions The cost‐effectiveness acceptance of nirsevimab was highly subject to drug cost and effectiveness of nirsevimab, RSV‐LRTI incidence, and RSV–LRTI‐related consequences.

While the large majority of parents in the U.S. vaccinate their children according to the recommended immunization schedule, some parents have refused or delayed vaccinating, often citing safety concerns. In response to public concern, the U.S. Institute of Medicine (IOM) evaluated existing research regarding the safety of the recommended immunization schedule. The IOM concluded that although available evidence strongly supported the safety of the currently recommended schedule as a whole, additional observational research was warranted to compare health outcomes between fully vaccinated children and those on a delayed or alternative schedule. In addition, the IOM identified the Vaccine Safety Datalink (VSD) as an important resource for conducting this research. Guided by the IOM findings, the Centers for Disease Control and Prevention (CDC) commissioned a White Paper to assess how the VSD could be used to study the safety of the childhood immunization schedule. Guided by subject matter expert engagement, the resulting White Paper outlines a 4 stage approach for identifying exposure groups of undervaccinated children, presents a list of health outcomes of highest priority to examine in this context, and describes various study designs and statistical methods that could be used to analyze the safety of the schedule. While it appears feasible to study the safety of the recommended immunization schedule in settings such as the VSD, these studies will be inherently complex, and as with all observational studies, will need to carefully address issues of confounding and bias. In light of these considerations, decisions about conducting studies of the safety of the schedule will also need to assess epidemiological evidence of potential adverse events that could be related to the schedule, the biological plausibility of an association between an adverse event and the schedule, and public concern about the safety of the schedule.

Despite the fundamental role of vaccines in the decline of infant mortality, parents may decide to decline vaccination for their own children. Many factors may influence this decision, such as the belief that the infant immune system is weakened by vaccines, and concerns have been raised about the number of vaccines and the early age at which they are administered. Studies focused on the infant immune system and its reaction to immunizations, summarized in this review, show that vaccines can overcome those suboptimal features of infant immune system that render them more at risk of infections and of their severe manifestations. In addition, many vaccines have been shown to improve heterologous innate and adaptive immunity resulting in lower mortality rates for fully vaccinated children. Thus, multiple vaccinations are necessary and not dangerous, as infants can respond to several antigens as well as when responding to single stimuli. Current immunization schedules have been developed and tested to avoid vaccine interference, improve benefits and reduce side effects compared to single administrations. The infant immune system is therefore capable, early after birth, of managing several antigenic challenges and exploits them to prompt its development.

Although vaccine coverage in infants in sub-Saharan Africa is high, this is estimated at the age of 6–12 months. There is little information on the timely administration of birth dose vaccines. The objective of this study was to assess the timing of birth dose vaccines (hepatitis B, BCG and oral polio) and reasons for delayed administration in The Gambia. We used vaccination data from the Farafenni Health and Demographic Surveillance System (FHDSS) between 2004 and 2014. Coverage was calculated at birth (0–1 day), day 7, day 28, 6 months and 1 year of age. Logistic regression models were used to identify demographic and socio-economic variables associated with vaccination by day 7 in children born between 2011 and 2014. Most of the 10,851 children had received the first dose of hepatitis B virus (HBV) vaccine by the age of 6 months (93.1%). Nevertheless, only 1.1% of them were vaccinated at birth, 5.4% by day 7, and 58.4% by day 28. Vaccination by day 7 was associated with living in urban areas (West rural: adjusted OR (AOR)=6.13, 95%CI: 3.20–11.75, east rural: AOR=6.72, 95%CI: 3.66–12.33) and maternal education (senior-educations: AOR=2.43, 95%CI: 1.17–5.06); and inversely associated with distance to vaccination delivery points (≧2km: AOR=0.41, 95%CI: 0.24–0.70), and Fula ethnicity (AOR=0.60, 95%CI: 0.40–0.91). Vaccine coverage in The Gambia is high but infants are usually vaccinated after the neonatal period. Interventions to ensure the implementation of national vaccination policies are urgently needed.

The United States Advisory Committee on Immunization Practices (ACIP) is a federal advisory committee that develops written recommendations for use of vaccines licensed by the Food and Drug Administration (FDA) for the U.S. civilian population. Vaccine development and disease outbreaks contributed to the need for a systematized, science-based, formal mechanism for establishing national immunization policy in this country. Formed in 1964, the ACIP was charged with this role. The committee has undergone significant changes in structure and operational activities during its 50-year history. The ACIP works closely with many liaison organizations to develop its immunization recommendations, which are harmonized among key professional medical societies. ACIP vaccine recommendations form two immunization schedules, which are updated annually: (1) the childhood and adolescent immunization schedule and (2) the adult immunization schedule. Today, once ACIP recommendations are adopted by the Director of the Centers for Disease Control and Prevention and the Secretary of the Department of Health and Human Services, these recommendations are published in Morbidity and Mortality Weekly Report (MMWR), become official policy, and are incorporated into the appropriate immunization schedule.

Vaccinations in Australia are reportable to the Australian Immunisation Register (AIR). Following major immunisation policy initiatives, the New South Wales (NSW) Public Health Network undertook an audit to estimate true immunisation coverage of NSW children at one year of age, and explore reasons associated with under‐reporting. Cross‐sectional survey examining AIR immunisation records of a stratified random sample of 491 NSW children aged 12≤15 months at 30 September 2017 who were >30 days overdue for immunisation. Survey data were analysed using population weights. Estimated true coverage of fully vaccinated one‐year‐old children in NSW is 96.2% (CI:95.9‐96.4), 2.1% higher than AIR reported coverage of 94.1%. Of the children reported as overdue on AIR, 34.9% (CI:30.9‐38.9) were actually fully vaccinated. No significant association was found between under‐reporting and socioeconomic status, rurality or reported local coverage level. Data errors in AIR uploading (at provider level) and duplicate records contributed to incorrect AIR coverage recording. Despite incentives to record childhood vaccinations on AIR, under‐reporting continues to be an important contributor to underestimation of true coverage in NSW. More reliable transmission of encounters to AIR at provider level and removal of duplicates would improve accuracy of reported coverage.

Vaccines are among the most safe and effective public health interventions to prevent serious disease and death.Because of the success of vaccines, most Americans today have no firsthand experience with such devastating illnesses as polio or diphtheria.Health care providers who vaccinate young children follow a schedule prepared by the U.S.

Background. The recommended schedule for receipt of 2-dose human rotavirus vaccine (HRV) coincides with receipt of the first and second doses of diphtheria, pertussis, and tetanus vaccine (ie, 6 and 10 weeks of age, respectively). Alternative schedules and additional doses of HRV have been proposed and may improve vaccine performance in low-income countries. Methods. In this randomized trial in rural Ghana, HRV was administered at ages 6 and 10 weeks (group 1), 10 and 14 weeks (group 2), or 6, 10, and 14 weeks (group 3). We compared serum antirotavirus immunoglobulin A (IgA) seroconversion (≥20 U/mL) and geometric mean concentrations (GMCs) between group 1 and groups 2 and 3. Results. Ninety-three percent of participants (424 of 456) completed the study per protocol. In groups 1, 2, and 3, the IgA seroconversion frequencies among participants with IgA levels of <20 U/mL at baseline were 28.9%, 37.4%, and 43.4%, respectively (group 1 vs group 3, P = .014; group 1 vs group 2, P = .163). Postvaccination IgA GMCs were 22.1 U/mL, 26.5 U/mL, and 32.6 U/mL in groups 1, 2, and 3, respectively (group 1 vs group 3, P = .038; group 1 vs group 2, P = .304). Conclusions. A third dose of HRV resulted in increased seroconversion frequencies and GMCs, compared with 2 doses administered at 6 and 10 weeks of age. Since there is no correlate of protection, a postmarketing effectiveness study is required to determine whether the improvement in immune response translates into a public health benefit in low-income countries. Clinical Trials Registration. NCT015751.

Pneumococcal conjugate vaccines (PCV) were first licensed for use with 3 primary doses in infancy and a booster dose. The evidence for the effects of different schedules was examined in this systematic review and meta-analysis. We searched 12 databases and trial registers up to March 2010. We selected randomised controlled trials (RCTs), cohort and case–control studies making direct comparisons between PCV schedules with (2p) or (3p) primary doses, with (+1) or without (+0) a booster dose. We extracted data on clinical, nasopharyngeal carriage and immunological outcomes and used meta-analysis to combine results where appropriate. Seropositivity levels (antibody concentration ≥0.35μg/ml) following 3p and 2p PCV schedules were high for most serotypes (5 RCTs). Differences between schedules were generally small and tended to favour 3p schedules, particularly for serotypes 6B and 23F; between-study heterogeneity was high. Seropositivity levels following 3p+1 and 2p+1 schedules were similar but small differences favouring 3p+1 schedules were seen for serotypes 6B and 23F. We did not identify any RCTs reporting clinical outcomes for these comparisons. In 2 RCTs there was weak evidence of a reduction in carriage of S. pneumoniae serotypes included in the vaccine when 3p+0 schedules were compared to 2p+0 at 6 months of age. Most data about the relative effects of different PCV schedules relate to immunological outcomes. Both 3p and 2p schedules result in high levels of seropositivity. The clinical relevance of differences in immunological outcomes between schedules is not known. There is an absence of clinical outcome data from RCTs with direct comparisons of any 2p with any 3p PCV schedule.

AbstractObjectivesTo characterize the clinical severity of covid-19 associated with the alpha, delta, and omicron SARS-CoV-2 variants among adults admitted to hospital and to compare the effectiveness of mRNA vaccines to prevent hospital admissions related to each variant.DesignCase-control study.Setting21 hospitals across the United States.Participants11 690 adults (≥18 years) admitted to hospital: 5728 with covid-19 (cases) and 5962 without covid-19 (controls). Patients were classified into SARS-CoV-2 variant groups based on viral whole genome sequencing, and, if sequencing did not reveal a lineage, by the predominant circulating variant at the time of hospital admission: alpha (11 March to 3 July 2021), delta (4 July to 25 December 2021), and omicron (26 December 2021 to 14 January 2022).Main outcome measuresVaccine effectiveness calculated using a test negative design for mRNA vaccines to prevent covid-19 related hospital admissions by each variant (alpha, delta, omicron). Among patients admitted to hospital with covid-19, disease severity on the World Health Organization’s clinical progression scale was compared among variants using proportional odds regression.ResultsEffectiveness of the mRNA vaccines to prevent covid-19 associated hospital admissions was 85% (95% confidence interval 82% to 88%) for two vaccine doses against the alpha variant, 85% (83% to 87%) for two doses against the delta variant, 94% (92% to 95%) for three doses against the delta variant, 65% (51% to 75%) for two doses against the omicron variant; and 86% (77% to 91%) for three doses against the omicron variant. In-hospital mortality was 7.6% (81/1060) for alpha, 12.2% (461/3788) for delta, and 7.1% (40/565) for omicron. Among unvaccinated patients with covid-19 admitted to hospital, severity on the WHO clinical progression scale was higher for the delta versus alpha variant (adjusted proportional odds ratio 1.28, 95% confidence interval 1.11 to 1.46), and lower for the omicron versus delta variant (0.61, 0.49 to 0.77). Compared with unvaccinated patients, severity was lower for vaccinated patients for each variant, including alpha (adjusted proportional odds ratio 0.33, 0.23 to 0.49), delta (0.44, 0.37 to 0.51), and omicron (0.61, 0.44 to 0.85).ConclusionsmRNA vaccines were found to be highly effective in preventing covid-19 associated hospital admissions related to the alpha, delta, and omicron variants, but three vaccine doses were required to achieve protection against omicron similar to the protection that two doses provided against the delta and alpha variants. Among adults admitted to hospital with covid-19, the omicron variant was associated with less severe disease than the delta variant but still resulted in substantial morbidity and mortality. Vaccinated patients admitted to hospital with covid-19 had significantly lower disease severity than unvaccinated patients for all the variants.