Strategies for expanding childhood vaccination in the Americas following the COVID-19 pandemic

Objective

To provide an overview of the status of the childhood vaccination schedule in the Americas, outline program structures, and identify updated implementation strategies to improve vaccination coverage following the COVID-19 pandemic.

Methods

A group of experts in pediatrics, epidemiology, vaccines, and global and public health discussed the current status of the childhood vaccination schedule in the Americas, describing the program structure and identifying new implementation strategies that have the potential to improve vaccination coverage in the post-pandemic context, after the challenges COVID-19 presented for more than two years.

Results

The Americas currently face a high risk of resurgence of diseases that were previously controlled or eliminated. Therefore, it is important to find new strategies to educate citizens on the risks associated with lower vaccination rates, especially in children.

Conclusions

New strategies along with strong mobilization of the population and advocacy by citizens are necessary to prevent antivaccination groups from gaining a stronger presence in the region and jeopardizing the credibility of the Expanded Program on Immunization.

Impact of hepatitis B birth dose on immune response in Pakistani children: an open-label, non-inferiority randomized controlled trial, implications for achieving SDG target

BACKGROUND

Despite presence of hyperendemic areas, the national immunisation schedule in Pakistan does not include a hepatitis B birth dose, placing newborns at an additional risk of acquiring hepatitis B. This study aimed to assess the impact of adding hepatitis B birth dose in existing national vaccination schedule.

METHODS

An open label, randomised controlled non-inferiority trial enrolled 296 healthy near-term mothers to intervention and control groups. Newborns in the intervention group received a hepatitis B birth dose along with routine immunisation vaccines, while control group newborns received vaccinations under the national schedule. Seroprotection was measured and compared at birth and 8 weeks after administering the third dose of pentavalent vaccine. The risk ratio of seroprotection was computed and compared with the delta value set at 5%.

RESULTS

The study found that 95.8% of infants in the intervention group achieved seroprotection, which was significantly higher than the control group's 58.7%. The difference in risk ratio of seroprotection was 1.62 (CI95: 1.37-1.93), with the upper limit of the CI below the delta margin, confirming non-inferiority. The time interval between birth and the first hepatitis B immunisation shot was a predictor of seroprotection, with an odds ratio of 1.79 (CI95: 1.01-2.9).

CONCLUSION

Our study indicates that adding a hepatitis B birth dose to the immunisation schedule in Pakistan is non-inferior to the existing one. This can also contribute towards Pakistan's achievement of the SDG target of reducing hepatitis B surface antigen seroprevalence in children under 5 years of age.

TRIAL REGISTRATION NUMBER

NCT04870021.

Potential serotype-specific effectiveness against IPD of pneumococcal conjugate vaccines V114 and PCV20 in children given a 2+1 dosing regimen

BACKGROUND

Next generation, higher valency pneumococcal conjugate vaccines (PCVs) are assessed and licensed by comparing the immune response across serotypes shared with the PCVs that are standard of care for prevention of pneumococcal disease.

METHODS

Using a previously qualified method we predicted the serotype-specific vaccine effectiveness (VE) against invasive pneumococcal disease of V114 and PCV20 for the serotypes shared with PCV13 in an EU, Russian, and Australian pediatric population that is recommended to receive a 2 + 1 dosing regimen.

RESULTS

The estimated protective antibody concentrations ranged from 0.03 (serotype 23F) to 1.49 µg/mL (serotype 19F). Predicted VE values for V114 ranged from 79% (serotype 5) to 100% (serotype 23F). V114 had comparable effectiveness to PCV13 for all but one of shared serotypes, with predicted higher effectiveness (in V114) against serotype 3 (93% vs. 65%). Predicted VE values for PCV20 ranged from 47% (serotype 3) to 91% (serotype 14). PCV20 predicted VE was lower than PCV13's for serotypes 4, 19F, 23F, 1, 3, 5, 6A, 7F, and 19A.

CONCLUSIONS

Predicted serotype-specific VE values suggest that, with a 2 + 1 dosing regimen, V114 will have greater effectiveness than PCV20 against PCV13 serotypes, particularly for the still-prevalent serotype 3. Real-world VE studies will ultimately provide clarity on the effectiveness of novel PCVs and support further confidence in and/or improvements to modeling efforts.

Multi-level quality improvement strategies to optimize HPV vaccination starting at the 9-year well child visit: Success stories from two private pediatric clinics

HPV vaccination rates remain far below goal, leaving many adolescents unprotected against future HPV-related cancers. Starting HPV vaccine at age 9 may improve timely preteen vaccination. The "HPV Vax at 9" Quality Improvement intervention paired HPV vaccination with 9- and 10-year well child visits and was piloted at two pediatric clinics (n = 9 sites) in Washington between 2018 and 2022. Supporting interventions included standardized immunization schedule posters in exam rooms, electronic medical record supports, provider and staff training, strong provider recommendations, printed educational resources, and peer-to-peer champion coaching. Provider and clinic acceptance was high with HPV vaccine administration occurring at 68-86% of the 9- and 10-year well child visits. During the first year, HPV initiation rates at age 9-10 increased by 30% or more at each clinic. Sustained improvements in initiation and series completion were seen with completion at age 11-12 rising as much as 40% from 22 to 62%. Downward pressure of the COVID-19 pandemic on HPV vaccination rates was mitigated. Pairing HPV vaccine with 9- and 10-year well child visits, posting the standardized immunization schedule, and instituting EMR supports for HPV at 9 may be effective and sustainable strategies to simplify clinic workflows and increase timely HPV vaccination.

Impact of an Intervention to Promote the Vaccination of Patients with Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) have a dysregulated immune system, being at high risk of opportunistic infections. Low vaccination rates hinder the prevention of such diseases. Therefore, we implemented an intervention to increase vaccination rates, and we aimed to evaluate the effect. We determined the change in professionals and the change in the vaccination rates after the intervention. A quasi-experimental study was carried out using data from 31 December 2016 to 31 December 2021. First, healthcare professionals specializing in IBD agreed on a vaccination protocol; then, this protocol was passed on to the professionals involved in vaccination. We evaluated the perception of knowledge, capacity, and intention to vaccinate patients with IBD among the professionals before and after the intervention with a survey. We also described the effectiveness of the intervention for already diagnosed patients and compared the vaccination rates between patients diagnosed prior to the intervention and newly diagnosed patients. The intervention resulted in an improved perception of knowledge, capacity, and intention to vaccinate patients with IBD among the professionals (p < 0.05). Moreover, during the post-intervention period, in the 315 patients, the vaccination rate increased for all immune-preventable diseases (p < 0.05). The professionals positively valued the intervention, and compliance with the recommended vaccination protocol in patients with IBD improved significantly.

Temporal trend of the dropout rate and vaccination coverage of the triple viral vaccine in Brazil, 2014-2021

MAIN RESULTS

Annual vaccination coverage was below 95% in Brazil. The second dose of the vaccine showed stationary and decreasing trends in the country's Federative Units. The dropout rate varied greatly throughout the study period.

IMPLICATIONS FOR SERVICES

The results found regarding the trends serve to inform and point to the urgency of planning actions aimed at improving coverage of the triple viral vaccine nationally in Brazil.

PERSPECTIVES

Investments in enhanced training of epidemiological surveillance professionals and enhanced computerized systems are necessary, with a view to continuous monitoring, to support actions to promote better and timely vaccine coverage.

OBJECTIVE

to analyze the temporal trend of coverage and dropout rate for triple viral vaccine in Brazil, according to the country's Federative Units and Macro-Regions, between 2014 and 2021.

METHODS

this was an ecological time series study, using data from the National Immunization Program Information System and the Live Birth Information System; joinpoint regression models were used.

RESULTS

in Brazil as a whole annual vaccination coverage was below 95% and ranged from 92.3% (2015) to 54.4% (2021); the second dose of the vaccine showed a decreasing temporal trend in the period (average change over the period = -5.8; 95%CI -10.5;-0.8); the temporal trends were stationary and decreasing in the country's Federative Units; the dropout rate ranged from 22.2% (2014) to 37.4% (2021).

CONCLUSION

there was a downward trend in vaccination coverage and an increase in the dropout rate in Brazil as a whole and in the country's Federative Units.

Predictors for Uptake of Vaccines Offered during the Second Year of Life: Second Dose of Measles-Containing Vaccine and Meningococcal Serogroup A-Containing Vaccine, Ghana, 2020

BACKGROUND

Understanding the drivers of coverage for vaccines offered in the second year of life (2YL) is a critical focus area for Ghana's life course approach to vaccination. This study characterizes the predictors of vaccine receipt for 2YL vaccines-meningococcal serogroup A conjugate vaccine (MACV) and the second dose of measles-containing vaccine (MCV2)-in Ghana.

METHODS

1522 children aged 18-35 months were randomly sampled through household surveys in the Greater Accra Region (GAR), Northern Region (NR), and Volta Region (VR). The association between predictors and vaccination status was modeled using logistic regression with backwards elimination procedures. Predictors included child, caregiver, and household characteristics.

RESULTS

Coverage was high for infant vaccines (>85%) but lower for 2YL vaccines (ranging from 60.2% for MACV in GAR to 82.8% for MCV2 in VR). Predictors of vaccination status varied by region. Generally, older, first-born children, those living in rural settlements and those who received their recommended infant vaccines by their first birthday were the most likely to have received 2YL vaccines. Uptake was higher among those with older mothers and children whose caregivers were aware of the vaccination schedule.

CONCLUSIONS

Improving infant immunization uptake through increased community awareness and targeted strategies, such as parental reminders about vaccination visits, may improve 2YL vaccination coverage.

Evaluating immune responses to pneumococcal vaccines

Streptococcus pneumoniae (pneumococcus) is a significant cause of bacterial infections ranging from mild infections affecting the respiratory tract such as otitis media and sinusitis to severe diseases including bacteremia, pneumonia, and invasive pneumococcal disease (IPD) (eg, meningitis, septic arthritis, and endocarditis). Pneumococcal vaccines were first developed in the 1970s as capsular pneumococcal polysaccharide vaccines, which were T-cell independent and hence lacked immunologic memory. Subsequently in the year 2000, pneumococcal conjugate vaccines (PCV) conjugated to a protein to increase immunogenicity were developed and made commercially available. The increasing number of pneumococcal serotypes identified and the expanding pipeline of PCV vaccines with improved immunogenicity have significantly reduced the morbidity and mortality associated with IPD in high-risk patients. Pneumococcal vaccines also play an important role in the diagnosis and immunophenotyping of children and adults with inborn errors of immunity (IEI) given the increasing diversity/heterogeneity of IEI presenting with primary and/or specific antibody deficiency. Other than the quantitation of serotype levels in routine clinical care, other measurements of immune response including the functional activity of antibodies, antibody avidity, cell-mediated immunity, and immunological memory remain limited to clinical trials during vaccine development.

Immune response after rabies pre-exposure prophylaxis and a booster dose in Australian bat carers

Periodic vaccination against rabies is essential for individuals at continuing risk of rabies exposure. There is limited evidence on long-term immunogenicity after a 3-dose intramuscular (3IM) pre-exposure prophylaxis (PrEP) and single IM booster dose, thus current guideline recommendations differ in the interval for serology tests following PrEP and boosters. This study investigated post-PrEP and post-booster persistence of antibodies in Australian bat carers. Bat carers who received 3IM PrEP/booster doses and had post-PrEP/booster serology test results were included. The proportion of antibody-negative (<0.5 EU/mL) individuals after PrEP/booster dose were examined. Three hundred and five participants (65.6% females, median age at PrEP 43.1 years) were included. The proportion who were antibody-negative varied depending on the time between 3IM PrEP and the serology test: 8.0% <1 year, 29.8% 1-2 years, 21.2% 2-3 years and 7.7% >3 years. Ninety-one participants receiving booster doses were further assessed. Only one participant was antibody-negative at >3 years after receiving one IM booster dose. Our findings support that a serology test should be performed 1 year after 3IM PrEP, followed by first booster if required. Rabies antibodies persist for many years after receiving the booster doses. The interval between subsequent serology tests and the first booster dose should be no longer than 3 years. Future studies are required to provide more insight into the most appropriate timing of subsequent boosters.

Factors Affecting Human Papillomavirus Vaccine Trends in the United States of America

Background Routine immunization of both girls and boys starting from nine years of age with the human papillomavirus (HPV) vaccine is the current recommendation. The objective of this retrospective study using National Health and Nutrition Examination Survey data was to evaluate the influence of sociodemographic factors on the series initiation and completion of the HPV vaccine from 2011 to 2020. Methodology The chi-square test was used to examine the statistical significance of the association between categorical variables and receipt of the HPV vaccine. The Cochran-Armitage test for trend was employed to assess the statistical significance of temporal trends in risk factors associated with rates of HPV vaccination. These trends were further quantified by a significant rate ratio by comparing them against the most recent survey years. Results HPV vaccine uptake was higher in the 9-14-year age group across survey years and had increased for both males and females over that time. The first dose of the HPV vaccine was most likely to be received by the 11-18-year age group. In the most recent survey of 2017-2020, the highest number of vaccination series completion was achieved for Gardasil®. Conclusions Improved physician efforts and strategies to vaccinate males, low socioeconomic strata patients, and ethnic minorities in more numbers are needed.

Recommendations for modernizing infant vaccination schedules with combination vaccines in Colombia and Peru

The objective of this article was to consider the vaccination challenges in Colombia and Peru and the role of pediatric combination vaccines in overcoming these challenges. Barriers to including new vaccines with more antigens remain apparent in parts of these countries, where vaccine-preventable diseases in infants continue to be a major problem. The challenges include the heterogeneity of vaccine coverage within each country and in neighboring countries, which can contribute to poor rates of vaccination coverage; the adverse impact of the inward migration of unvaccinated individuals, which has favored the re-emergence of vaccine-preventable diseases; vaccine shortages; and the impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and the associated shifts in health care resources. To improve the coverage of pediatric vaccines in Colombia and Peru, it will be necessary to ensure the widespread integration into vaccine schedules of combination vaccines containing diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b and hepatitis B antigens with a three-dose primary series delivered at 2, 4 and 6 months of age followed by a booster at 18 months of age. Such vaccines play important roles in preventing diphtheria, tetanus and pertussis; eradicating polio; and providing boosting against H. influenzae type b.

Immunogenicity and reactogenicity of heterologous immunization schedules with COVID-19 vaccines: a systematic review and network meta-analysis

BACKGROUND

Data on the immunogenicity and safety of heterologous immunization schedules are inconsistent. This study aimed to evaluate the immunogenicity and safety of homologous and heterologous immunization schedules.

METHODS

Multiple databases with relevant studies were searched with an end date of October 31, 2021, and a website including a series of Coronavirus disease 2019 studies was examined for studies before March 31, 2022. Randomized controlled trials (RCTs) that compared different heterologous and homologous regimens among adults that reported immunogenicity and safety outcomes were reviewed. Primary outcomes included neutralizing antibodies against the original strain and serious adverse events (SAEs). A network meta-analysis (NMA) was conducted using a random-effects model.

RESULTS

In all, 11 RCTs were included in the systematic review, and nine were ultimately included in the NMA. Among participants who received two doses of CoronaVac, another dose of mRNA or a non-replicating viral vector vaccine resulted in a significantly higher level of neutralizing antibody than a third CoronaVac 600 sino unit (SU); a dose of BNT162b2 induced the highest geometric mean ratio (GMR) of 15.24, 95% confidence interval [CI]: 9.53-24.39. Following one dose of BNT162b2 vaccination, a dose of mRNA-1273 generated a significantly higher level of neutralizing antibody than BNT162b2 alone (GMR = 1.32; 95% CI: 1.06-1.64), NVX-CoV2373 (GMR = 1.60; 95% CI: 1.16-2.21), or ChAdOx1 (GMR = 1.80; 95% CI: 1.25-2.59). Following one dose of ChAdOx1, a dose of mRNA-1273 was also more effective for improving antibody levels than ChAdOx1 (GMR = 11.09; 95% CI: 8.36-14.71) or NVX-CoV2373 (GMR = 2.87; 95% CI: 1.08-3.91). No significant difference in the risk for SAEs was found in any comparisons.

CONCLUSIONS

Relative to vaccination with two doses of CoronaVac, a dose of BNT162b2 as a booster substantially enhances immunogenicity reactions and has a relatively acceptable risk for SAEs relative to other vaccines. For primary vaccination, schedules including mRNA vaccines induce a greater immune response. However, the comparatively higher risk for local and systemic adverse events introduced by mRNA vaccines should be noted.

REGISTRATION

PROSPERO; https://www.crd.york.ac.uk/PROSPERO/ ; No. CRD42021278149.

Beyond Vaccination Coverage: Population-Based Measurement of Early Childhood Immunization Schedule Adherence

The immunization schedule recommended by the U.S. Advisory Committee on Immunization Practices (ACIP) provides a structure for how 10 different vaccine series should be administered to children in the first 18 months of life. Progress toward US early childhood immunization goals has largely focused on measuring vaccination coverage at age 24 months. However, standard vaccination coverage measures do not reflect whether children received vaccine doses by recommended ages, or whether vaccines were given concomitantly, per the schedule. In this paper, we describe innovations in population-level measurement of immunization schedule adherence through quantifying vaccination timeliness and undervaccination patterns. Measuring vaccination timeliness involves comparing when children received vaccine doses relative to ACIP age recommendations. To assess undervaccination patterns, children's vaccination histories are analyzed to determine whether they were vaccinated consistent with the ACIP schedule. Some patterns, such as spreading out vaccines across visits, are indicative of parental hesitancy. Other patterns, such as starting all recommended series but missing doses, are largely indicative of other immunization services delivery challenges. Since 2003, at least 12 studies have used National Immunization Survey-Child, immunization information system, or integrated health plan data to measure vaccination timeliness or undervaccination patterns at national or state levels. Moving forward, these novel measures can be leveraged for population-based surveillance of vaccine confidence, and for distinguishing undervaccination due to parental vaccine hesitancy from undervaccination due to other causes. Broader adoption of these measures can facilitate identification of targeted strategies for improving timely and routine early childhood vaccination uptake across the United States.

Review of scientific evidence to support recommendations of the full-dose DTaP-IPV vaccination in pre-school age children in Italy

INTRODUCTION

Two vaccine formulations are available to prevent diphtheria, tetanus, pertussis, and poliomyelitis: the pediatric full-dose (DTaP-IPV) and the reduced dose formulation (dTap-IPV). Different immunization schedules are internationally recommended for the pre-school booster dose.

AREAS COVERED

International and Italian recommendations, scientific evidence on immunogenicity and safety of DTaP/dTap vaccines to support the full dose as a pre-school booster and Italian vaccination coverage (VC) up to adolescence.

EXPERT OPINION

The WHO recommends a '3+1' schedule with DTaP vaccine for primary immunization, followed by a pre-school booster with DTaP or dTap vaccine. In Italy, a '2+1' schedule, with no booster in the second year, and a pre-school booster dose are recommended with DTPa-IPV vaccines. Studies showed a non-inferior immunogenicity in dTap vaccinees in pre-school age; nevertheless, the antibody titers were usually greater in children vaccinated with DTaP, while lower frequencies of adverse events were recorded in children receiving dTap. Italian VCs for pre-school and adolescent boosters have not been satisfactory, which further reduced during the COVID-19 period. In Italy, the pre-school booster offers the last chance to receive a full dose of DTaP vaccine, thus, representing the most suitable intervention to provide lasting protection in children.

Impact of the COVID-19 Pandemic on Human Papillomavirus Vaccination in Brazil

Objective: To analyze the number of applied HPV vaccine doses before (from April 2019 to March 2020) and after (from April 2020 to September 2020) social distancing measures in response to the COVID-19 pandemic in states and regions of Brazil. Methods: Ecological time-series study, using data from the Brazilian National Immunization Program (PNI). Using the Mann-Whitney test, we evaluated the difference between the median number of applied doses during the periods April 2019 to March 2020 and from April 2020 to September 2020. Spatial analysis identified clusters with a high or low percentage reduction in the median applied doses. Prais-Winsten regression models identified temporal trends in the applieddoses from both periods. Results: There was a significant reduction in the median HPV vaccine doses applied, formation of spatial clusters and, after a sharp drop in the number of applieddoses during the months following social distancing. There was a tendency to increase the applied vaccines doses. Conclusion: The COVID-19 pandemic resulted in reduction of the number of HPV vaccine doses applied as a possible effect of restrictive measures caused by the pandemic.

[Vaccination, a public health tool]

Vaccination remains a major public health tool, the only one that has enabled the eradication of an infectious disease, smallpox. In this fight, biotechnological innovations point to considerable progress in the development of new vaccines. However, whatever technical progress is made, the impact of a vaccination program will depend on its performance and on the support of the population.

Comparison of immune responses induced by two or three doses of an alum-adjuvanted inactivated SARS-CoV-2 vaccine in mice

Waning antibodies and rapidly emerging variants are challenges for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccine development. Adjusting existing immunization schedules and further boosting strategies are under consideration. Here, the immune responses induced by an alum‐adjuvanted inactivated SARS‐CoV‐2 vaccine in mice were compared among immunization schedules with two or three doses. For the two‐dose schedule, a 0–28‐day schedule induced 5‐fold stronger spike‐specific IgG responses than a 0–14‐day schedule, with only a slight elevation of spike‐specific cellular immunity 14 days after the last immunization. A third homologous boost 2 or 5 months after the second dose for the 0–28‐day schedule slightly strengthened humoral responses (1.3‐fold for the 0–1–3‐month schedule, and 1.8‐fold for the 0–1–6‐month schedule) 14 days after the last immunization. Additionally, a third homologous boost (especially with the 0–1–3‐month schedule) induced significantly stronger cell‐mediated immunity than both two‐dose immunization schedules for all indexes tested, with a response similar to that induced by a one‐dose heterologous boost with BNT162b2 in clinical trials, according to cellular immunity analysis (1.5‐fold). These T cell responses were Th2 oriented, with good CD4+ and CD8+ memory. These results may offer clues for applying a homologous boosting strategy for alum‐adjuvanted inactivated SARS‐CoV‐2 vaccines.

Health Extension Workers Knowledge and Associated Factors on Child Immunization in Bako Tibe, West Shewa, Oromia, Ethiopia: A Cross-Sectional Study

Purpose

To assess health extension workers knowledge of child immunization schedules and associated factors.

Methods

A cross-sectional study design was conducted among health extension workers working in Bako Tibe Woreda. The data were collected by using semi-structured questionnaires, and descriptive statistics were used to summarize the data. Chi-square (χ ²) was used to identify factors associated with the knowledge of health extension workers on the immunization schedules.

Results

The response rate of the study was 92.1% (58/63). All of the health extension workers included in the study were females. The majority of health extension workers 45 (77.59%) had satisfactory knowledge of the child immunization schedule. Educational status (χ ² = 11.05; P= 0.001), work experience of as health extension workers (χ ² = 6.22; P= 0.045), on job training on immunization (χ ² = 11.12; P= 0.002), marital status (χ ² = 6.30; P= 0.019) were factors associated with health extension workers knowledge.

Conclusion

The majority of health extension workers had satisfactory knowledge of the child immunization schedule. Educational status, work experience as health extension worker, on job training on immunization, and marital status were factors associated with the knowledge of health extension workers on the child immunization schedule.

Overview of the United States' Immunization Program

This manuscript describes the history, background, and current structure of the United States Immunization Program, founded upon public- and private-sector partnerships that include federal agencies, state and local health departments, tribal nations and organizations, healthcare providers, vaccine manufacturers, pharmacies, and a multitude of additional stakeholders. The Centers for Disease Control and Prevention sets the U.S. adult and childhood immunization schedules based on recommendations from the Advisory Committee on Immunization Practices. We review the current immunization schedules; describe the set of surveillance and other systems used to monitor the health impact, coverage levels, and safety of recommended vaccines; and note significant challenges. Vaccines have reduced the incidence of many diseases to historic lows in the US, and have potential to further reduce the burden of respiratory and other infectious diseases in the United States. Though the United States vaccination program has had notable successes in reducing morbidity and mortality from infectious disease, challenges-including disparities in access and vaccine hesitancy-remain. Supporting access to and confidence in vaccines as an essential public health intervention will not only protect individuals from vaccine-preventable diseases; it will also ensure the country is prepared for the next pandemic.

Evaluation of Antibody Response in Sows after Vaccination with Senecavirus A Vaccine and the Effect of Maternal Antibody Transfer on Antibody Dynamics in Offspring

Senecavirus A (SVA) is a newly porcine virus that has been detected in many countries since its first detection in pigs in Canada in 2007, and it remains endemic in many countries in Asia and America, which has become a substantial problem for the pig industry. Vaccination is a potentially effective strategy for the prevention and control of SVA infection. Our lab has developed a SVA vaccine candidate previously. In this study, the antibody response to the prepared vaccine in sows and their offspring was evaluated. Vaccination of sows with inactivated SVA vaccines during pregnancy elicited SVA-specific virus-neutralizing antibodies. Vaccination with a high dose of SVA vaccine followed a booster immunization contributed to a long-term duration of the persistence of maternally derived neutralizing antibodies (MDAs) in the milk of the sows (>14 days). In contrast, vaccination with a single low dose of SVA vaccine resulted in a short-term persistence of MDAs in the milk (2–7 days). The MDAs could be efficiently transferred from the sows to their offspring through the colostrum/milk but not the umbilical cord blood. The antibody titers and the duration of the persistence of MDAs in the offspring are highly associated with the antibody levels in the milk from the sows. Vaccination of sows with a booster dose of SVA vaccine resulted in a longer-lasting MDAs in their offspring (persisted for at least 90 days). However, vaccination with the single low dose of vaccine only brought about 42 days of MDAs persistence in their offspring. The effect of MDAs on active immunization with SVA vaccine in offspring was further evaluated, which showed that vaccination of the SVA vaccine in the presence of MDAs at the titer of ≈1:64 or less could overcome the MDAs’ interference and give rise to effective antibody response. This will help for establishing the optimal times and schedules for SVA vaccination in pigs.

Estimating the Effectiveness of Rotavirus Vaccine Schedules

BACKGROUND

Important questions exist regarding the comparative effectiveness of alternative childhood vaccine schedules; however, optimal approaches to studying this complex issue are unclear.

METHODS

We applied methods for studying dynamic treatment regimens to estimate the comparative effectiveness of different rotavirus vaccine (RV) schedules for preventing acute gastroenteritis-related emergency department (ED) visits or hospitalization. We studied the effectiveness of six separate protocols: one- and two-dose monovalent rotavirus vaccine (RV1); one-, two-, and three-dose pentavalent rotavirus vaccine (RV5); and no RV vaccine. We used data on all infants to estimate the counterfactual cumulative risk for each protocol. Infants were censored when vaccine receipt deviated from the protocol. Inverse probability of censoring-weighted estimation addressed potentially informative censoring by protocol deviations. A nonparametric group-based bootstrap procedure provided statistical inference.

RESULTS

The method yielded similar 2-year effectiveness estimates for the full-series protocols; weighted risk difference estimates comparing unvaccinated children to those adherent to either full-series (two-dose RV1, three-dose RV5) corresponded to four fewer hospitalizations and 12 fewer ED visits over the 2-year period per 1,000 children. We observed dose-response relationships, such that additional doses further reduced risk of acute gastroenteritis. Under a theoretical intervention to fully vaccinate all children, the 2-year risk differences comparing full to observed adherence were 0.04% (95% CI = 0.03%, 0.05%) for hospitalizations and 0.17% (95% CI = 0.14%, 0.19%) for ED visits.

CONCLUSIONS

The proposed approach can generate important evidence about the consequences of delaying or skipping vaccine doses, and the impact of interventions to improve vaccine schedule adherence.

Non-inferior antibody levels for HPV16/18 after extended two-dose schedules compared with a six-month interval: findings of a systematic review and meta-analysis

Protection after human papillomavirus (HPV) vaccination can be maximized by optimizing vaccination schedules. We systematically reviewed immunogenicity and effectiveness of HPV vaccines administered 6 months apart compared with longer intervals. Seroconversion to vaccine-type HPV was non-inferior for 12- compared with 6-month intervals, but inconclusive for comparison of 36-96 months with 6 months. A 12-month interval showed non-inferior (margin 0.5) vaccine-type HPV antibody responses compared with a 6-month interval. Compared to 6 months, an interval of 36-96 months resulted in non-inferior antibody responses for HPV6 and high-risk types HPV16 and 18, but did not lead to a non-inferior antibody response for HPV11 (GMR 0.63, 95% CI:0.41-0.97). Data on the effectiveness of extended two-dose schedules were limited. Our findings indicate that HPV immunization programs could adopt a 12-month interval instead of 6 months for increased flexibility without compromising immunogenicity. Further evaluation to confirm the immunogenicity and effectiveness of intervals beyond 12 months is warranted.

Vaccine effectiveness following routine immunization with bivalent HPV vaccine: Protection against incident genital HPV infections from a reduced-dosing schedule

Background

In the Netherlands, the bivalent human papillomavirus (HPV) vaccine has been offered to preadolescent girls via the National Immunization Program in a 2-dose schedule since 2014. The current study estimates vaccine effectiveness (VE) against HPV infections up to 4 years postvaccination among girls eligible for routine 2-dose immunization.

Methods

A cohort study (HAVANA2) was used in which participants annually filled out an online questionnaire and provided a vaginal self-sample for determination of HPV by the SPF10-LiPA25 assay, able to detect 25 HPV types. VE against incident type-specific infections and pooled outcomes was estimated by a Cox proportional hazards model with shared frailty between the HPV types.

Results

In total, 2027 girls were included in the study, 1098 (54.2%) of whom were vaccinated with 2 doses. Highest incidence rate was 5.0/1000 person-years (HPV-51) among vaccinated participants and 9.1/1000 person-years (HPV-74) among unvaccinated participants. Adjusted pooled VE was 84.0% (95% confidence interval [CI], 27.0%–96.5%) against incident HPV-16/18 infections and 86.5% (95% CI, 39.5%–97.08%) against cross-protective types HPV-31/33/45.

Conclusions

Four years postvaccination, 2 doses of bivalent HPV vaccine were effective in the prevention of incident HPV-16/18 infections and provided cross-protection to HPV-31/33/45. Our VE estimates rival those from 3-dose schedules, indicating comparable protection by 2-dose schedules.

Immunogenicity of 2 and 3 Doses of the Quadrivalent Human Papillomavirus Vaccine up to 120 Months Postvaccination: Follow-up of a Randomized Clinical Trial

Background

Several countries have implemented a 2-dose (2D) human papillomavirus (HPV) vaccination schedule for adolescents based on immunobridging studies. We compared immunogenicity of 2D vs 3-dose (3D) schedules of the quadrivalent vaccine (4vHPV) up to 10 years after the first dose.

Methods

Girls aged 9–13 years were randomized to receive 2D or 3D and were compared with women aged 16–26 receiving 3D at day 1 and months 7, 24, and 120 after the first dose. Antibody levels for HPV6/11/16/18 were evaluated using the competitive Luminex immunoassay (cLIA) and total immunoglobulin G assay. Geometric mean titers (GMTs) and seropositivity rates were compared between the different groups at different time points. Noninferiority of GMT ratios was defined as the lower bound of the 2-sided 95% confidence interval (CI) being greater than 0.5. Kinetics of antibody titers over time among study groups were examined.

Results

At 120 months, data from 35 2D girls, 38 3D girls, and 30 3D women were used for analyses. cLIA seropositivity rates were above 95% for all HPV vaccine types and all schedules, except HPV18, with the lowest seropositivity observed among 3D women (60.0%; 95% CI, 40.6%–77.3%). GMT ratios (cLIA) for both 2D and 3D girls were noninferior to 3 doses in women for HPV6/11/16/18. Trends were comparable between assays.

Conclusions

GMTs for HPV6/11/16/18 after 2D or 3D of 4vHPV in girls were noninferior to 3D in adult women up to 120 months postvaccination. This study demonstrates long-term immunogenicity of the 2D HPV vaccine schedule.

Effect of an Electronic Order Set on Newborn Hepatitis B Immunization Rates

Objective

Hepatitis B is an infectious deoxyribonucleic acid virus which can cause significant morbidity and mortality. There is no current definitive treatment, however in the United States immunization is widely available. A paper published by the Advisory Committee on Immunization Practices/Centers for Disease Control (ACIP/CDC) in 2018 made updated recommendations regarding vaccination practices in the United States. The most notable change made was that all healthy newborns weighing ≥2000 g with a negative hepatitis B-status mother should receive hepatitis B immunization within 24 hours of birth. This quality improvement project studied the effect of the electronic medical record newborn admission order set, altered to reflect current societal recommendations, and the resulting newborn hepatitis B immunization rates.

Methods

The electronic medical record admission order set was modified to reflect the most recent recommendations made by ACIP/CDC. Hepatitis B immunization rates were then analyzed prior to and following the order set changes.

Results

The most significant effect was seen in the overall rate of hepatitis B immunization achieved prior to hospital discharge. In the 12 months before order set modifications were implemented the rate was 9.5%. Following electronic medical record changes it improved to over 90%. In addition, the immunization rate performed within the first 24 hours increased from 74.1% to 91.1%. Finally, these records were made accessible to outpatient providers via a statewide immunization database.

Conclusions

This project serves as an example of how modifying order sets can have a dramatic effect on ordering practices and therefore allows for quality improvement.

Predictors of 'Out-of-Pocket Expenditure' on Routine Immunization of Under-Five Children: A Regression Analysis

Introduction: ‘Out-of-pocket expenditure’ (OOPE) is the expenditures at the point of receiving health care directly by households which affects the economic stability of the household. When the expenditure on immunization of under-five children results in OOPE, it affects the motivation of parents for vaccination inversely.

Aim: This study was planned to evaluate the out-of-pocket expenditure and to assess predictors of OOPE on routine immunization practices.

Settings and design: This was a cross-sectional community-based study conducted from May to August 2019 at one of the immunization sites at primary health centers under a tertiary care institute of southern Rajasthan.

Material and methods: At the selected health facility, randomly 75% of beneficiaries of routine immunization were enrolled for the study. Data were collected using a pre-designed, pre-tested semi-structured questionnaire about direct and indirect expenses during the process of immunization incurred by the parents of the vaccinee by interview technique.

Results: In the study, 72.36% were infants, and 56.10% had first birth order. Mother accompanied nearly half of the vaccinee (49.6%) to the vaccination centre and the most used mode of transportation was the personal vehicle (63%). Mean loss of wages among parents/caretakers was 0.58 (±0.66) USD (median = 0.69; interquartile range (IQR) = 0.69; 95% confidence interval (CI) = 0.42-0.73) while average cost of transportation worn was 0.16 (±0.20) USD (median = 0.07; IQR = 0.21; 95% CI = 0.12-0.19) and mean duration of travelling to reach health facility was 11.87 (±7.53) minutes (median = 10; IQR = 10; 95% CI = 10.53-13.20). Vaccination at the centre was free of cost (zero USD) and no cost was incurred for drugs or registration. Average OPPE was 0.74 (±0.97) USD (median = 0.35; IQR = 0.62; 95% CI = 0.56-0.91) and regression analysis predicted significant contributors as age of vaccinee (p = 0.00; OR = 0.11; 95% CI = 0.04-0.34), religion (p = 0.04; OR = 0.34; 95% CI = 0.12-0.97) area of residence (p = 0.00; OR = 6.77; 95% CI = 2.37-19.32), birth order of vaccinee (p = 0.02; OR = 0.3; 95% CI = 0.11-0.85), longer waiting time (p = 0.03; OR = 0.16; 95% CI = 0.03-0.85), travelling time (p = 0.00; OR = 3.47; 95% CI = 1.49-8.09) and long distances (p = 0.00; OR = 10.40; 95% CI = 2.56-42.03) travelled to reach vaccination centre.

Conclusion: The hidden cost of vaccination in the form of loss of wages and time, travel cost due to stretched distance traveled by family members to accompany vaccinee to immunization facility is experienced as OOPE by the families and could be one of the impediments in vaccination coverage. Amendments in the existing policies are required to reduce this invisible cost of vaccination.

Timing of Intradermal Rabies Pre-exposure Prophylaxis Injections: Immunological Effect on Vaccination Response

INTRODUCTION

Rabies remains a global threat, with annually over 59,000 deaths. Intradermal (ID) pre-exposure prophylaxis (PrEP) is very efficient and reduces the need for rabies immunoglobulins. Not much is known about factors that influence the immune response to ID administered rabies vaccine. The aim of this study is to determine if variations in timing of vaccine administration and serology determination, age and gender have an influence on the levels of rabies virus neutralizing antibody (RVNA) after ID rabies vaccination.

MATERIALS AND METHODS

This is a retrospective study based on electronic health record vaccination data of Belgian military personnel who received ID rabies PrEP with a three injections regimen during the period 2014-2017. Serology was determined by using the RFFIT method. Fischer's exacts tests were used to evaluate the effect of each independent variable on RVNA levels.

RESULTS

In this study, 2,112 subjects were included. All but one seroconverted with a RVNA level ≥0.5 IU/mL. About 48% of subjects developed an antibody titer of >10 IU/mL, 36% had antibody levels 3-10 IU/mL and 16% had an antibody level 0.5-2.99 IU/mL. Statistically significant (p = 0.0018) higher RVNA levels are observed in the groups that received vaccination doses later as planned. Timing of serology determination also influenced RVNA levels significantly (p = 0.000). Antibody levels were significantly higher in females than in males (p = 0.000). Age did influence RVNA levels significantly (p = 0.022).

CONCLUSIONS

Timing of vaccine dose administration, timing of serology testing, sex and age do significantly influence the humoral B-cell response to ID administered rabies vaccine.

Clinical Decision Support for Immunization Uptake and Use in Immunization Health Information Systems

CONTEXT

In the United States, immunization recommendations and their associated schedules are developed by the Advisory Committee on Immunization Practices (ACIP). To assist with the translation process and better harmonize the outcomes of existing clinical decision support tools, the Centers for Disease Control and Prevention (CDC) created clinical decision support for immunization (CDSi) resources for each set of ACIP recommendations. These resources are continually updated and refined as new vaccine recommendations and clarifications become available and will be available to health information systems for a coronavirus disease 2019 (COVID-19) vaccine when one becomes available for use in the United States Objectives: To assess awareness of CDSi resources, whether CDSi resources were being used by immunization-related health information systems, and perceived impact of CDSi resources on stakeholders' work Design: Online surveys conducted from 2015-2019 including qualitative and quantitative questions Participants: The main and technical contact from each of the 64 CDC-funded immunization information system (IIS) awardees, IIS vendors, and electronic health record vendors Results: Awareness of at least one resource increased from 75% of respondents in 2015 to 100% in 2019. Use of at least one CDSi resource also increased from 47% in 2015 to 78% in 2019. About 80% or more of users of CDSi are somewhat or very highly satisfied with the resources and report a somewhat or very positive impact from using them Conclusion: As awareness and use of CDSi resources increases, the likelihood that patients receive recommended immunizations at the right time will also increase. Rapid and precise integration of vaccine recommendations into health information systems will be particularly important when a COVID-19 vaccine becomes available to help facilitate vaccine implementation.

[Assessment of vaccination status and booster vaccinations in adolescents attending school in Libreville, Gabon]

Introduction

La vaccination chez l'adolescent est particulière et le statut vaccinal de ce dernier est peu connu. L'objectif de cette étude était d'apprécier ce statut vaccinal et d'identifier les facteurs associés à la compliance vaccinale chez les adolescents scolarisés à Libreville.

Méthodes

Une enquête observationnelle transversale descriptive a été réalisée chez les élèves des classes de 6^edu Lycée national Léon MBA de Libreville.

Résultats

Au total, 304 élèves ont été inclus dans l'étude. L'âge moyen des élèves était de 11,60±1,20 ans et le sexe ratio était de 0,6. Deux cent soixante-six enfants (87,5%) vivaient avec leur géniteur direct (père et/ou mère). Le nombre moyen d'enfants par famille était de 4. Le taux de couverture vaccinale était de 78,3%. Le nombre d'enfants par famille n'était pas associée à la couverture vaccinale des vaccins du PEV (p=0,088), par contre les enfants vivant avec au moins l'un des parents avaient une meilleure couverture vaccinale respectivement par les vaccins du PEV (p=0,025) et les vaccins hors PEV (p=0,035). Les facteurs évoqués par les parents pour expliquer la non-vaccination étaient le manque d'information (30,59%), l'oubli (24,67%) et le manque de moyens financiers (12,82%).

Conclusion

La couverture vaccinale des adolescents scolarisés à Libreville semble relativement proche des objectifs du PEV, mais elle reste associée à la situation familiale. D'autres campagnes de sensibilisation seraient utiles pour améliorer cette couverture vaccinale au Gabon.

Matrix of strategic recommendations for immunization of health workers

Background

Health workers are at high risk of exposure to contagious diseases, many of which might be prevented through vaccination. According to the Brazilian labor legislation, vaccination is a right of workers and an obligation for employers.

Objective

To develop a matrix of strategic recommendations relative to the vaccination status of health workers as a function of the risks to which this occupational group is exposed.

Methods

Qualitative study performed at a Health Basic Unit in November and December 2016. We held three workshops with an average of 22 participants and following a problematization method based on the Maguerez arc approach. The data collected in the workshops were recorded on a field notebook.

Results

The selected method helped the participants gain insights the process of illness and healthcare. The workshops resulted in a matrix of recommendations of strategies to orient and monitor immunizations for health workers, including: information on vaccinations recommended for health workers, vaccination status updates and occupational health surveillance.

Conclusion

The present study provides grounds for occupational healthcare as concerns the vaccination status of the participants and other health workers. The resulting strategic recommendations aim at improving the vaccination status of health workers and thus reduce the risk of diseases preventable through immunizations, which might be a reason for sickness absenteeism, and even of indefinite sick leave.

Recommendations for the use of Japanese encephalitis vaccines

Japanese encephalitis (JE) is a mosquito-borne viral infection which is prevalent in Taiwan. The virus circulates in an enzootic cycle in pigs which serve as amplifying hosts. Outbreaks typically occur during summer. A universal vaccination program using 4-shot mouse brain-derived inactivated vaccine has successfully controlled JE epidemics in Taiwan since 1968. More than 90% of JE cases in recent years were older than 20 years in Taiwan. Because of several drawbacks, mouse brain-derived vaccine has been replaced by newer generation JE vaccines, including inactivated Vero cell-derived vaccine and live chimeric vaccine. The present article describes the recommendations in Taiwan for the use of new JE vaccines and the schedules for shifting between different JE vaccines.

Evaluation of the Impact of Meningococcal Serogroup A Conjugate Vaccine Introduction on Second-Year-of-Life Vaccination Coverage in Burkina Faso

BACKGROUND

After successful meningococcal serogroup A conjugate vaccine (MACV) campaigns since 2010, Burkina Faso introduced MACV in March 2017 into the routine Expanded Programme for Immunization schedule at age 15-18 months, concomitantly with second-dose measles-containing vaccine (MCV2). We examined MCV2 coverage in pre- and post-MACV introduction cohorts to describe observed changes regionally and nationally.

METHODS

A nationwide household cluster survey of children 18-41 months of age was conducted 1 year after MACV introduction. Coverage was assessed by verification of vaccination cards or recall. Two age groups were included to compare MCV2 coverage pre-MACV introduction (30-41 months) versus post-MACV introduction (18-26 months).

RESULTS

In total, 15 925 households were surveyed; 7796 children were enrolled, including 3684 30-41 months of age and 3091 18-26 months of age. Vaccination documentation was observed for 86% of children. The MACV routine coverage was 58% (95% confidence interval [CI], 56%-61%) with variation by region (41%-76%). The MCV2 coverage was 62% (95% CI, 59%-65%) pre-MACV introduction and 67% (95% CI, 64%-69%) post-MACV introduction, an increase of 4.5% (95% CI, 1.3%-7.7%). Among children who received routine MACV and MCV2, 93% (95% CI, 91%-94%) received both at the same visit. Lack of caregiver awareness about the 15- to 18-month visit and vaccine unavailability were common reported barriers to vaccination.

CONCLUSIONS

A small yet significant increase in national MCV2 coverage was observed 1 year post-MACV introduction. The MACV/MCV2 coadministration was common. Findings will help inform strategies to strengthen second-year-of-life immunization coverage, including to address the communication and vaccine availability barriers identified.

Practical Guide to Vaccination in All Stages of CKD, Including Patients Treated by Dialysis or Kidney Transplantation

Infection is a major cause of morbidity and mortality in patients with chronic kidney disease (CKD), including those receiving maintenance dialysis or with a kidney transplant. Although responses to vaccines are impaired in these populations, immunizations remain an important component of preventative care due to their favorable safety profiles and the high rate of infection in these patients. Most guidelines for patients with CKD focus on the importance of the hepatitis B, influenza, and pneumococcal vaccines in addition to age-appropriate immunizations. More data are needed to determine the clinical efficacy of these immunizations and others in this population and define optimal dosing and timing for administration. Studies have suggested that there may be a benefit to immunization before the onset of dialysis or transplantation because patients with early-stage CKD generally have higher rates of seroconversion. Because nephrologists often serve as primary care physicians for patients with CKD, it is important to understand the role of vaccinations in the preventive care of this patient population.

Comparison of anti-HBs persistence after hepatitis B vaccination on two-dose schedule and three-dose schedule among adults: results from a 12-year follow up study in China

Comparison of anti-HBs persistence after hepatitis B vaccination on two-dose schedule and three-dose schedule among adults is still controversial. In this study, adults were followed up at 12 years after the primary immunization. Three hundred and forty-one and 288 adults with age 15 through 40 years old were given anti-HBV vaccination on a 0-, 1-, and 6-month schedule or on a 0- and 6-month one, respectively (in 2003). Blood samples of 202 patients on 0-, 1- and 6-month schedule and 194 patients on 0- and 6-month regimen were collected at one month and twelve years (in 2015) after the primary series and anti-HBs levels were measured. The seroprotection rate for 3-dose schedule and 2-dose one was 71.78% (95%CI = 65.04%, 77.87%) and 53.61% (95%CI = 46.07%, 60.49%). The GMC of anti-HBs was 31 mIU/mL (95%CI = 24, 41) and 12 mIU/mL (95%CI = 9, 17), respectively. Participants using three doses had higher seroprotection rate and GMC (P < 0.001). Multivariable analysis showed that subjects with anti-HBs titers ≥100 mIU/ml just after the primary series had a higher probability of anti-HBs levels than <10 mIU/ml and 10-100 mIU/ml at follow-up (OR = 8.36, 95%CI: 3.41-20.49, P< 0.001; OR = 43.28, 95%CI: 11.45-163.51, P< 0.001; β = 0.77, 95%CI: 0.48-1.06, P< 0.001; β = 1.20, 95%CI: 0.86 ~ 1.54, P< 0.001). In conclusions, adults receiving HepB primary immunization on 0-, 1- and 6-month schedule might have more prolonged anti-HBs than those on 0-, 6-month schedule, although good anti-HBs persistence could be achieved after HepB immunization on both schedules.

Hepatitis A, B, and A/B vaccination series completion among US adults: A claims-based analysis

Hepatitis A and B disease burden persists in the US. We assessed hepatitis A and hepatitis B vaccination series completion rates among 350,240 commercial/Medicare and 12,599 Medicaid enrollees aged ≥19 years. A vaccination series was considered as completed provided that the minimum interval between doses, as defined by the CDC, and the minimum number of doses were reached. We stratified completion rates by vaccine type (i.e. monovalent or bivalent) at initial vaccination for each cohort. In the commercial/Medicare cohort, the series completion rate was 32.0% for hepatitis A and 39.6% for hepatitis B among those who initiated with a monovalent vaccine, and it was 36.2% for hepatitis A and 48.9% for hepatitis B among those who initiated with a bivalent vaccine. In the Medicaid cohort, the series completion rate was 21.0% for hepatitis A and 24.0% for hepatitis B among those who initiated with a monovalent vaccine, and it was 19.0% for hepatitis A and 24.6% for hepatitis B among those who initiated with a bivalent vaccine. In conclusion, hepatitis A and B vaccination series completion rates were low, and appeared to be lower among Medicaid than among commercial/Medicare enrollees. Commercial/Medicare enrollees who initiated with a bivalent vaccine had higher series completion rates than those who initiated with monovalent vaccines – an observation that was not made among Medicaid enrollees.

Immunogenicity and safety of a second dose of a measles-mumps-rubella vaccine administered to healthy participants 7 years of age or older: A phase III, randomized study

The introduction of vaccination programs against measles, mumps, and rubella (MMR) led to significant global reduction in morbidity and mortality from these diseases. The currently recommended MMR vaccination schedule in the United States of America comprises 2 vaccine doses typically administered at 12–15 months and 4–6 years, respectively. Considering recent outbreaks in the USA, catch-up vaccination with an additional dose of MMR vaccine could contribute to outbreak control and community protection. This phase III, observer-blind, randomized controlled trial (NCT02058563) assessed the immunogenicity and safety of a dose of the MMR-RIT vaccine (Priorix, GSK) compared to MMR II vaccine (control; M-M-R II, Merck&Co Inc.) in ≥7-year-olds who had received ≥1 previous dose of MMR vaccine. We assessed anti-measles, anti-mumps, and anti-rubella antibody geometric mean concentrations (GMCs; primary endpoint) and seroresponse rates (SRRs) at day 42 post-vaccination. Solicited, unsolicited, and serious adverse events (AEs) were recorded. The according-to-protocol cohort for immunogenicity included 869 participants (MMR-RIT: N = 433; MMR II: N = 436). We observed anti-measles, anti-mumps, and anti-rubella antibody GMCs of 1790.2 mIU/mL, 113.5 EU/mL, and 76.1 IU/mL, respectively, and SRRs of 98.8%, 98.4%, and 99.5%, respectively, after a dose of MMR-RIT; non-inferiority compared to MMR II was demonstrated. Both vaccines showed comparable reactogenicity profiles; the most common solicited AEs were injection site redness and pain, and fever (MMR-RIT: 12.2%, 11.8%, and 3.0%; MMR II: 11.7%, 11.5%, and 5.2%, respectively). The dose of MMR-RIT induced robust immune responses that were not inferior to those of MMR II, and was well tolerated.

Low Rates of Vaccination for Herpes Zoster in Older People Living With HIV

Herpes zoster (HZ) occurs at a higher age-specific rate in people living with HIV (PLWH) than in the general population. We implemented a quality improvement study to assess herpes zoster vaccine (HZV) usage among PLWH, assess HZV usage after additional reminders/prompts, and identify barriers to HZV among older PLWH. HZV rates in PLWH were determined in six institutions with varying payment structures. For the intervention, Part 1, PLWH eligible for HZV at the University of Colorado were identified, and providers were notified of patient eligibility. In Part 2, in addition to provider notification, an order for HZV was placed in the patient's chart before a clinic appointment. HZ vaccination rates ranged from 1.5% to 42.4% at six sites. Before the intervention, 21.3% of eligible University of Colorado patients had received HZV. An additional 8.3% received HZV with Part 1 and 17.8% with Part 2 interventions. At completion, a total of 53.2% of eligible patients had received HZV through routine clinical care or the interventions. Insurance coverage concern was cited as a common reason for not receiving HZV. Minor adverse reactions occurred in 26.7% patients and did not require medical care. HZV coverage was low at a majority of sites. Clinical reminders with links to vaccination orders or preplaced vaccination orders led to improved HZV coverage in our clinic, but published guidelines for use of HZV in PLWH and improvement in logistic or insurance barriers to HZV receipt are paramount to improved HZV coverage.

Challenges and opportunities for meningococcal vaccination in the developing world

Meningococcal disease continues to be a life threatening infection with high morbidity and mortality even in appropriately treated patients. Meningococcal vaccination plays a major role in the control of the disease; however, implementing vaccination remains problematic in the developing world. The objective of this review is to identify the challenges facing the use of meningococcal vaccines in the developing world in order to discuss the opportunities and available solutions to improve immunization in these countries. Inadequate epidemiologic information necessary to implement vaccination and financial challenges predominate. Multiple measures are needed to achieve the successful implementation of meningococcal conjugate vaccination programs that protect against circulating serogroups in developing countries including enhanced surveillance systems, financial support and aid through grants, product development partnerships that are the end result of effective collaboration and communication between different interdependent stakeholders to develop affordable vaccines, and demonstration of the cost-effectiveness of new meningococcal vaccines.

Methods for addressing "innocent bystanders" when evaluating safety of concomitant vaccines

PURPOSE

The need to develop methods for studying the safety of childhood immunization schedules has been recognized by the Institute of Medicine and Department of Health and Human Services. The recommended childhood immunization schedule includes multiple vaccines in a visit. A key concern is safety of concomitant (same day) versus separate day vaccination. This paper addresses a methodological challenge for observational studies using a self-controlled design to investigate the safety of concomitant vaccination.

METHODS

We propose a process for distinguishing which of several concomitantly administered vaccines is responsible for increased risk of an adverse event while adjusting for confounding due to relationships between effect modifying risk factors and concomitant vaccine combinations. We illustrate the approach by re-examining the known increase in risk of seizure 7 to 10 days after measles-mumps-rubella (MMR) vaccination and evaluating potential independent or modifying effects of other vaccines.

RESULTS

Initial analyses suggested that DTaP had both an independent and potentiating effect on seizure. After accounting for the relationship between age at vaccination and vaccine combination, there was little evidence for increased risk of seizure with same day administration of DTaP and MMR; incidence rate ratio, 95% confidence interval 1.2 (0.9-1.6), P value = θ.226.

CONCLUSION

We have shown that when using a self-controlled design to investigate safety of concomitant vaccination, it can be critically important to adjust for time-invariant effect modifying risk factors, such as age at time of vaccination, which are structurally related to vaccination patterns due to recommended immunization schedules.

[Reasons some children under 5 do not get vaccinated in four Colombian citiesMotivos por que não são vacinadas crianças menores de cinco anos em quatro cidades colombianas]

Objetivo.

Conocer las barreras y los motivos de no vacunación en niños y niñas menores de cinco años en algunas ciudades de Colombia.

Métodos.

Diseño cualitativo basado en entrevistas y grupos focales a personal de salud y cuidadores en cuatro ciudades colombianas seleccionadas de acuerdo a diferentes coberturas de vacunación y densidades poblacionales

Resultados.

Se identificaron diferentes factores que pueden influir en el incumplimiento de los esquemas de vacunación en los dos municipios con baja cobertura, como el temor a la reacción posvacunal, las condiciones socioeconómicas, geográficas y de seguridad de la población, las condiciones laborales del personal de vacunación, los problemas administrativos y económicos y el desarrollo precario de los sistemas de información.

Conclusiones.

Desde el punto de vista cualitativo, los equipos de vacunación y los cuidadores destacaron aspectos sociales e institucionales que contribuyen o limitan el cumplimiento de las coberturas de vacunación en las ciudades que participaron en el estudio.

Use of cellular phone contacts to increase return rates for immunization services in Kenya

Introduction

In Kenya, failure to complete immunization schedules by children who previously accessed immunization services is an obstacle to ensuring that children are fully immunized. Home visit approaches used to track defaulting children have not been successful in reducing the drop-out rate.

Methods

This study tested the use of phone contacts as an approach for tracking immunization defaulters in twelve purposively-selected facilities in three districts of western Kenya. For nine months, children accessing immunization services in the facilities were tracked and caregivers were asked their reasons for defaulting.

Results

In all of the facilities, caregiver phone ownership was above 80%. In 11 of the 12 facilities, defaulter rates between pentavalent1 and pentavalent3 vaccination doses reduced significantly to within the acceptable level of < 10%. Caregivers provided reliable contact information and health workers positively perceived phone-based defaulter communications. Tracking a defaulter required on average 2 minutes by voice and Ksh 6 ($ 0.07). Competing tasks and concerns about vaccinating sick children and side-effects were the most cited reasons for caregivers defaulting. Notably, a significant number of children categorised as defaulters had been vaccinated in a different facility (and were therefore “false defaulters”).

Conclusion

Use of phone contacts for follow-up is a feasible and cost-effective method for tracking defaulters. This approach should complement traditional home visits, especially for caregivers without phones. Given communication-related reasons for defaulting, it is important that immunization programs scale-up community education activities. A system for health facilities to share details of defaulting children should be established to reduce “false defaulters”.

Pneumonia in Elderly Australians: Reduction in Presumptive Pneumococcal Hospitalizations but No Change in All-Cause Pneumonia Hospitalizations Following 7-Valent Pneumococcal Conjugate Vaccination

BACKGROUND

Studies evaluating long-term trends in hospitalizations coded as pneumonia following introduction of the 7-valent pneumococcal vaccine (PCV7) are sparse, especially in adults. We extended our previous analysis to 6.5 years after the "3 + 0" PCV7 schedule was introduced in Australia in 2005.

METHODS

We estimated vaccine impact on hospitalizations coded as pneumonia (pneumococcal/lobar, other specified, unspecified, and all-cause) using a multivariate negative binomial regression model of monthly hospitalization rates by age group for the pre-PCV7 (July 1998 to December 2004) and post-PCV7 (January 2005 to June 2011) periods, adjusting for vaccination coverage. Changes in pneumonia hospitalizations were measured as incidence rate ratios.

RESULTS

A total of 791 000 hospitalizations coded as pneumonia were identified; unspecified causes accounted for >85%. Reductions in pneumonia coded as pneumococcal/lobar were statistically significant in all age groups and greatest in children. Significant reductions in all-cause pneumonia were seen only in children aged <2 years (32%; 95% confidence interval [CI], 28%-37%) and 2-4 years (20%; 95% CI, 14%-27%), with no significant changes in other age groups, including adults aged 65-74 (4%; 95% CI, -3% to 10%), 75-84 (2%; 95% CI, -4% to 9%), and ≥85 years (3%; 95% CI, -3% to 10%).

CONCLUSIONS

We could not replicate reductions of 23% in all-cause pneumonia 7-9 years post-PCV7 introduction reported for adults aged ≥85 years in the United States. This could be attributable to vaccine program factors, differing proportions of pneumonia due to pneumococci, or data limitations. More data from countries with differing PCV schedules and from the PCV13 era are needed to inform vaccination strategies for elderly adults.

Parents' choices and rationales for alternative vaccination schedules: a qualitative study

BACKGROUND

A growing number of parents adopt alternative vaccination schedules for their children. A better understanding of parents' rationales for these choices is needed to guide vaccine decision making.

METHODS

We conducted 24 semistructured telephone interviews with parents of 12- to 36-month-olds and analyzed data using an inductive approach.

RESULTS

We identified 5 alternative vaccination approaches: "Dr Sears" schedule, shot-limiting approach, selective delay or decline, visit-by-visit decisions, and refusal of all vaccines. Parents who adopted alternative approaches expressed a desire for more control of exposure to vaccine ingredients; vaccine safety, immune system burden, and perceived disease risk were articulated as concerns.

CONCLUSIONS

Parents who adopt alternative vaccination schedules can be classified in defined subgroups based on their decision-making approaches, and many describe considered reasons to support their actions. Communications that acknowledge and address those reasons may be better able to engage parents and ultimately enhance the process of decision making about vaccines.

Mixing of diphtheria, tetanus, and acellular pertussis (DTaP) vaccines in a population of children in managed care

The Advisory Committee on Immunization Practices recommends administering diphtheria, tetanus and acellular pertussis (DTaP) vaccines to children at 2, 4, 6, 15-18 months, and 4-6 y of age; preferably with the same-brand vaccine for the whole series. We estimated age-appropriate DTaP dose completion and the proportion of children receiving a "mixed" DTaP vaccination series (ie, including DTaP vaccines from ≥ 2 brands) across the 3 milestones. Commercially-insured children born between 01/01/2003 and 04/30/2011 were identified from United States health insurance claims data and assigned to ≥ 1 of 3 study cohorts based on the duration of continuous health plan enrollment: 1) birth to <8 months; 2) birth to <20 months; 3) birth to <7 years. Dose completion and brand mixing of the first 3, first 4 or all 5 doses were measured in the respective cohorts. Administered DTaP vaccinations were identified in claims data and classified by brand (based on vaccine components and manufacturer). The analysis included children who received ≥ 2 DTaP vaccinations and had known brand information for all doses. Age-appropriate dose completion was 77% with 3 doses (<8 months cohort), 71% with 4 doses (<20 months cohort), and 85% with 5 doses (<7 years cohort). Mixed DTaP series were received by 4.7% (95% confidence interval [CI]: 4.6%-4.7%) in the <8 months cohort, 29.0% (95% CI: 28.6%-29.4%) in the <20 months cohort, and 39.0% (95% CI: 34.5, 43.6) in the <7 years cohort. DTaP mixing was just 4.7% for the first 3 doses but subsequently increased with the number of administered doses.

American Academy of Pediatrics Committee on Infectious Diseases. Updated recommendations on the use of meningococcal vaccines

Since the last policy statement from the American Academy of Pediatrics (AAP) concerning meningococcal vaccine was published in 2011, 2 meningococcal conjugate vaccines have been licensed for use in infants (Hib-MenCY-TT and MenACWY-CRM). The Centers for Disease Control and Prevention (CDC) has published new recommendations, "Prevention and Control of Meningococcal Disease: Recommendations of the Advisory Committee on Immunization Practices," which have been endorsed by the AAP. However, the CDC recommendations were published before licensure of MenACWY-CRM for infant use. This policy statement updates the AAP recommendations for use of meningococcal vaccines in children and adolescents. A more comprehensive review of background and technical information can be found in the CDC publication.

Systematic review of the effect of pneumococcal conjugate vaccine dosing schedules on vaccine-type nasopharyngeal carriage

BACKGROUND

Pneumococcal conjugate vaccines (PCV) reduce nasopharyngeal carriage of vaccine type (VT) pneumococci, an important driver of vaccine programs' overall benefits. The dosing schedule that best reduces carriage is unclear.

METHODS

We performed a systematic review of English language publications from 1994 to 2010 (supplemented post hoc with studies from 2011) reporting PCV effects on VT carriage to assess variability in effect by dosing schedule.

RESULTS

We identified 32 relevant studies (36 citations) from 12,980 citations reviewed. Twenty-one (66%) evaluated PCV7; none used PCV10 or PCV13. Five studies evaluated 2 primary doses and 13 three primary doses. After the first year of life, 14 evaluated 3-dose primary series with PCV booster (3+1), seven 3 doses plus 23-valent polysaccharide booster "3+1PPV23," five "3+0," four "2+1," three "2+1PPV23" and two "2+0." Four studies directly compared schedules. From these, 3 primary doses reduced VT carriage more than 2 doses at 1-7 months following the series (1 study significant; 2 borderline). In a study, the 2+1 schedule reduced VT carriage more than 2+0 at 18, but not at 24 months of age. One study of a 23-valent pneumococcal polysaccharide vaccine booster showed no effect. All 16 clinical trials with unvaccinated controls and 11 observational studies with before-after designs showed reduction in VT carriage.

CONCLUSIONS

The available literature demonstrates VT-carriage reduction for 2+0, 2+1, 3+0 and 3+1 PCV schedules, but not for 23-valent pneumococcal polysaccharide vaccine booster. Comparisons between schedules show that 3 primary doses and a 2+1 schedule may reduce carriage more than 2 primary doses and a 2+0 schedule, respectively.

Systematic review of the effect of pneumococcal conjugate vaccine dosing schedules on vaccine-type invasive pneumococcal disease among young children

BACKGROUND

Pneumococcal conjugate vaccines (PCV) are being implemented globally using a variety of different schedules. The optimal schedule to maximize protection of vaccinated children against vaccine-type invasive pneumococcal disease (VT-IPD) is not known.

METHODS

To assess the relative benefit of various PCV dosing schedules, we conducted a systematic review of studies published in English from 1994 to 2010 (supplemented post hoc with studies from 2011) on PCV effectiveness against VT-IPD among children targeted to receive vaccine. Data on 2-dose and 3-dose primary series, both with and without a booster ("2+0," "2+1," "3+0" and "3+1"), were included. For observational studies using surveillance data or case counts, we calculated percentage reduction in VT-IPD before and after PCV introduction.

RESULTS

Of 4 randomized controlled trials and 31 observational studies reporting VT-IPD among young children, none evaluated a 2+0 complete series, 7 (19%) evaluated 2+1, 4 (11%) 3+0 and 27 (75%) 3+1. Most (86%) studies were from North America or Europe. Only 1 study (observational) directly compared 2 schedules (3+0 vs. 3+1); results supported the use of a booster dose. In clinical trials, vaccine efficacy ranged from 65% to 71% with 3+0 and 83% to 94% with 3+1. Surveillance data and case counts demonstrate reductions in VT-IPD of up to 100% with 2+1 (6 studies) or 3+1 (17 studies) schedules and up to 90% with 3+0 (2 studies). Reductions were observed as early as 1 year after PCV introduction.

CONCLUSIONS

These data support the use of 2+1, 3+0 and 3+1 schedules, although most data of PCV impact on VT-IPD among young children are from high-income countries using 3+1. Differences between schedules for impact on VT-IPD are difficult to discern based on available data.

Methods for a systematic review of pneumococcal conjugate vaccine dosing schedules

BACKGROUND

Streptococcus pneumoniae causes a considerable amount of morbidity and mortality in children <5. However, pneumococcal conjugate vaccines (PCVs) can prevent much of this burden. Until recently, PCVs were mostly available only in developed countries using a variety of dosing schedules. As more lower income countries make decisions to introduce PCV into their national immunization programs, an optimal schedule with which to administer PCV has become a key policy question.

METHODS

We performed a systematic review of English literature published from 1994 to 2010 on the effects of PCV dosing schedules on immunogenicity, nasopharyngeal carriage, invasive pneumococcal disease and pneumonia. Data were independently double abstracted and cleaned for analysis. Descriptive analyses were performed.

RESULTS

We identified 12,980 citations from the literature search (12,976) and secondary means (44). Double review of titles and abstracts yielded 769 articles that underwent full data abstraction. Of these, 350 were further analyzed and are presented in separate reports in this supplement.

CONCLUSIONS

This article presents the methods utilized in our systematic review. Because of the heterogenity of the study methods of the reports identified by this review, we did not conduct formal meta-analyses. However, these methods allow us to present a full landscape of the literature on PCV dosing schedules.