Facilitators and Barriers to Successful Revaccination after Hematopoietic Stem Cell Transplantation among Adult Survivors: A Scoping Review

Post-transplantation revaccination uptake of childhood vaccines in adult hematopoietic stem cell transplantation (HSCT) survivors is suboptimal, increasing the risk of infectious morbidity and mortality within this population. We systematically reviewed the literature for factors related to revaccination uptake, as well as the barriers and facilitators that affect successful revaccination. We conducted a scoping review searching PubMed, CINAHL, Embase, and Web of Science in March 2023. Two independent reviewers performed study selection using the complete dual review process. Data were extracted using a standard form. Factors were characterized as demographic, clinical, or social determinants of health that affected revaccination uptake. Barriers and facilitators were categorized using the constructs from the World Health Organization Behavioural and Social Drivers Framework. Our searches yielded 914 sources, from which 15 publications were selected (5 original research and 10 quality improvement initiatives). More than one-half of the reports listed factors associated with poorer uptake, predominately clinical factors, followed by social determinants of health, then demographic factors. Nearly all the reports described barriers to successful revaccination uptake, with most of these falling into the "practical issues" construct. Most of the reports described facilitators, nearly all related to health care system improvements associated with improved revaccination uptake. Although this review provides a good starting point for understanding impediments to successful revaccination after HSCT, this review reveals that we lack sufficient evidence to drive targeted interventions to improve uptake. More research is needed, focusing on survivors' voices to inform our knowledge of barriers and facilitators to complete revaccination after HSCT, exploring behavioral and social drivers within this population, and examining the care delivery models that may complicate vaccine delivery in this population.

Surname order and revaccination intentions during the COVID-19 pandemic

Teachers in Japanese schools employ alphabetical surname lists that call students sooner, with surnames appearing early on these lists. We conducted Internet surveys nearly every month from March 2020 to September 2022 with the same participants, wherein we asked participants where the alphabetical columns of their childhood and adult surnames were located. We aimed to identify how surname order is important for the formation of noncognitive skills. During the data collection period, the COVID-19 vaccines became available; Japanese people could receive their third dose starting in December 2021. The 19th wave of the survey was conducted in January 2022. Therefore, to examine how a surname's alphabetical order could influence intention to revaccinate, we used a subsample of data from December 2021 to September 2022. The major findings were as follows. Women with early surnames had an approximately 4% stronger likelihood of having such intentions than men with early surnames. Early name order was more strongly correlated with revaccination intention among women than among men. The surname effect for women was larger when a mixed-gender list was used compared with when it was not used. This effect was only observed for childhood surnames and not for adult surnames.

Clinical assessment of a point-of-care assay to determine protective vaccinal antibody titers to canine viral diseases

Guidelines recommend that dogs are vaccinated for canine distemper virus (CDV), canine parvovirus (CPV), and canine adenovirus (CAV) every 3 years. Alternatively, their antibody titers are measured and vaccines given when titers fall below a protective threshold. In this study, a point-of-care (POC) assay was compared to hemagglutination inhibition (for CPV) and virus neutralization (for CAV and CDV) assays to predict the need for revaccination Ninety-two dogs presented for vaccination were enrolled. The POC assay indicated protective titers against CDV in 79/80, CPV in 89/90, and CAV in 91/91 dogs with reference standard antibody measurements that were over a protective threshold. The sensitivity of the POC assay for to detect protective concentrations of CDV antibodies was 99% (95% confidence interval [CI 95%], 93.3-99.9%). Ten dogs were falsely considered protected against CDV by the POC assay with a specificity of 17% (CI 95%, 3.0-44.8%). The sensitivity of the POC assay for protective concentrations of CPV titers was 99% (CI 95%, 93.9-99.9%). The sensitivity of the POC assay to detect protective concentrations of CAV antibodies was 100% (CI 95%, 95.9-100%). Only classifying high-positive CDV and CPV titers on the POC assay as protective improved assay specificity to 100%, but sensitivity decreased to 51% and 76% respectively. This POC assay had a high sensitivity for the detection of protective antibody titers; however, some dogs were falsely categorized as protected, especially for CDV.

The impact of BCG dose and revaccination on trained immunity

The innate immune system can display heterologous memory-like responses termed trained immunity after stimulation by certain vaccinations or infections. In this randomized, placebo-controlled trial, we investigated the modulation of Bacille Calmette-Guérin (BCG)-induced trained immunity by BCG revaccination or high-dose BCG administration, in comparison to a standard dose. We show that monocytes from all groups of BCG-vaccinated individuals exerted increased TNFα production after ex-vivo stimulation with various unrelated pathogens. Similarly, we observed increased amounts of T-cell-derived IFNγ after M. tuberculosis exposure, regardless of the BCG intervention. NK cell cytokine production, especially after heterologous stimulation with the fungal pathogen Candida albicans, was predominantly boosted after high dose BCG administration. Cytokine production capacity before vaccination was inversely correlated with trained immunity. While the induction of a trained immunity profile is largely dose- or frequency independent, baseline cytokine production capacity is associated with the magnitude of the innate immune memory response after BCG vaccination.

Efficacy and safety of COVID-19 vaccination in patients with cirrhosis

BACKGROUND

The clinical efficacy and safety of vaccination against novel coronavirus disease 2019 (COVID-19) in patients with cirrhosis have not been evaluated yet.

AIM

To evaluate the clinical efficacy and safety of vaccination against COVID-19 in patients with cirrhosis.

METHODS

This was a retrospective cohort study of patients with cirrhosis. The first cohort included patients vaccinated with Gam-COVID-Vac (Sputnik V); the second one consisted of unvaccinated controls.

RESULTS

The study included 89 vaccinated patients and 148 unvaccinated ones. There were 4 cases of COVID-19 in the vaccinated group and 24 cases in the unvaccinated group (P = 0.035). No severe cases of COVID-19 were revealed in the vaccinated group, while there were 12 ones in the unvaccinated group (P = 0.012) with 10 deaths detected (P = 0.012). The vaccine efficacy was 69.5% (95% confidence interval [CI]: 18.5%-94.4%) against symptomatic cases of COVID-19, 100% (95%CI: 25.1%-100.0%) against severe cases, and 100% (95%CI: 1.6%-100.0%) against death associated with COVID-19. The efficacy of full vaccination with revaccination against symptomatic cases of COVID-19 was 88.3% (95%CI: 48.0%-99.6%). The overall mortality rate was higher in the unvaccinated group than in the vaccinated group (17.1% vs 3.0%; P = 0.001). Higher Child-Turcotte-Pugh class cirrhosis (hazard ratio [HR] = 4.13, 95%CI: 1.82-9.35) and higher age (HR = 1.08, 95%CI: 1.04-1.15) were independent predictors of overall mortality, while vaccination had a protective effect (HR = 0.09, 95%CI: 0.01-0.76). There was no significant difference in liver-related mortality (P = 0.135) or the incidence of liver decompensation (P = 0.077), bleeding esophageal varices (P = 0.397), and vascular events (P = 0.651) between the two groups of patients.

CONCLUSION

Vaccination against COVID-19 in patients with cirrhosis is effective and safe.

Reasons for Individuals' COVID-19 vaccine hesitations and changing decisions over time: A longitudinal qualitative study

Objective

COVID-19 is a serious public health problem. Therefore, it is important to vaccinate the community. This study was aimed at examining the reasons for individuals' COVID-19 vaccine hesitations, and decisions that have changed over time.

Material and methods

This was a prospective longitudinal qualitative study.

Results

Confidence, fear, conspiracy theories, belief, and social pressure play a role in vaccine hesitancy. The most important factor in the changing decisions of individuals who are hesitant about vaccination is pressure. Confidence and fear also lead to a change of decision. However, it was remarkable that most of the participants who were vaccinated due to pressure did not want to be revaccinated.

Conclusions

Governments, media, vaccine companies, health professionals, and scientists should act together to increase the vaccination rates of individuals.

Longitudinal assessment of nonavalent vaccine HPV types in a sample of sexually active African American women from ten U.S. Cities

BACKGROUND

Chronic infection with high-risk human papillomavirus is a necessary cause for cervical carcinogenesis. This study examined prevalence of nonavalent vaccine preventable HPV types over four months among sexually active women in the United States.

METHODS

This sub-study obtained meta-data for 80 of the 1,365 women (18-25 years), enrolled in the BRAVO study, a randomized, open-label trial of home screening and treatment of asymptomatic bacterial vaginosis at high-risk for sexually transmitted infections conducted between 2008 and 2013. Participants were randomized to treatment or standard-of-care, and followed every 2-months for 12 months. Stored vaginal swabs from the first three visits were tested for the nine vaccine preventable HPV types using quantitative PCR. Prevalence and associated 95% confidence intervals for the HPV types were assessed using R (version 3.6.1).

RESULTS

The average age of the participants was 21.5 (SD ± 2.11) years, with 60% having ever been pregnant and all were African-American. Majority (71%) reported ≥ two sex partners in the prior year with 89% having unprotected vaginal sex and 45% having a new sex partner in the prior year. About 30% had ≥ one of the nine nonavalent vaccine HPV types at all three time points over a period of four months, 15% at two of any three visits, 19% at one of the three visits and 36% were negative for all nine vaccine HPV types at all time points. The most frequently detected HPV vaccine types were 52, 58, 16, and 18. The prevalence of any vaccine HPV types, and high-risk HPV types was 63.8% and 58.8%, respectively.

CONCLUSIONS

Our findings suggest that HPV vaccination which is currently recommended for all unvaccinated persons through age 26 years, is likely to be more beneficial than previously thought as nonavalent HPV vaccine was not available during the time these data were collected.

Repeated exposure to an MF-59 adjuvanted quadrivalent subunit influenza vaccine (aQIV) in children: Results of two revaccination studies

BACKGROUND

Pediatric adjuvanted seasonal influenza vaccines induce higher immune responses and have the potential to confer better protection against influenza among young vaccine-naïve children. Limited data describe benefits and risks of repeated administration of adjuvanted influenza vaccines in children. Two revaccination studies assess the safety and immunogenicity of repeated exposure to an MF59-adjuvanted quadrivalent influenza vaccine (aQIV; Fluad®) compared to routine non-adjuvanted quadrivalent influenza vaccine (QIV).

METHODS

Children previously enrolled in the parent study, who received vaccination with aQIV or nonadjuvanted influenza vaccine (TIV or QIV), were recruited in Season 1 (n = 607) or Season 2 (n = 1601) of the extension trials. Season 1 participants remained in their original randomization groups (aQIV-aQIV or TIV-QIV); Season 2 subjects were re-randomized to either vaccine, resulting in four groups (aQIV-aQIV, aQIV-QIV, QIV-aQIV, or QIV-QIV). All subjects received a single-dose vaccination. Blood samples were taken for immunogenicity assessment prior to vaccination and 21 and 180 days after vaccination. Reactogenicity (Days 1-7) and safety were assessed in all subjects.

RESULTS

Hemagglutination inhibition (HI) geometric mean titer (GMT) ratios demonstrated superiority of aQIV revaccination over QIV revaccination for all strains in Season 1 and for A/H1N1, B/Yamagata, and B/Victoria in Season 2. Higher HI titers against heterologous influenza strains were observed after aQIV vaccination during both seasons. Mild to moderate severity and short duration reactogenicity was more common in the aQIV than QIV groups, but the overall safety profiles were similar to the parent study.

CONCLUSION

The safety and immunogenicity results from this study demonstrate benefit of aQIV for both priming and revaccination of children aged 12 months to 7 years.

BCG as a game-changer to prevent the infection and severity of COVID-19 pandemic?

The impact of COVID-19 is changing with country wise and depend on universal immunization policies. COVID-19 badly affects countries that did not have universal immunization policies or having them only for the selective population of countries (highly prominent population) like Italy, USA, UK, Netherland, etc. Universal immunization of BCG can provide great protection against the COVID-19 infection because the BCG vaccine gives broad protection against respiratory infections. BCG vaccine induces expressions of the gene that are involved in the antiviral innate immune response against viral infections with long-term maintenance of BCG vaccine-induced cellular immunity. COVID-19 cases are reported very much less in the countries with universal BCG vaccination policies such as India, Afghanistan, Nepal, Bhutan, Bangladesh, Israel, Japan, etc. as compared to without BCG implemented countries such as the USA, Italy, Spain, Canada, UK, etc. BCG vaccine provides protection for 50–60 years of immunization, so the elderly population needs to be revaccinated with BCG. Several countries started clinical trials of the BCG vaccine for health care workers and elderly people. BCG can be uses as a prophylactic treatment until the availability of the COVID-19 vaccine.

Revaccination management of a large cohort of pediatric patients following a potential lapse in cold storage

INTRODUCTION

In a pediatric clinic in California (US), 3823 patients were vaccinated with potentially-compromised vaccines following lapses in cold storage chain management between February 2014 and April 2015. A revaccination program was initiated in May 2015. Families were contacted by mail and encouraged to discuss follow-up options with their care team, namely: revaccination, serological testing and/or revaccination, or no further action. This study aimed: to understand which families were more likely to respond to the outreach, and to engage in any testing and/or revaccination; to determine whether or not vaccination with these potentially-compromised vaccines elicited sufficient immune response in pediatric patients; and to estimate the program cost.

METHODS

Patients who had received potentially-compromised vaccines were identified, and relevant data were extracted from their electronic health records. Logistic regression analyses were performed to identify factors associated with response to outreach, serological testing and/or revaccination.

RESULTS

3823 patients between 0 and 21 years received an average of 3.1 potentially-compromised vaccines. 2547 revaccinations were performed (1515 patients) and 544 patients had serological testing results. Non-immune titer levels were only reported for 3-4% and 8% of the tested patients who had received potentially-compromised tetanus and hepatitis B vaccines, respectively, and only for children two years old and younger. Three years after the revaccination program started, 77% of all cases were considered resolved and 62.5% of patients (1970/3152) who were administered potentially-compromised vaccines were either revaccinated or had seroprotective titers. Response to outreach and decision to choose serological testing and/or revaccinate were affected by patient age, race/ethnicity and zip code median income (p < 0.05).

CONCLUSION

We observed race/ethnicity, patient age and income differences in response to the outreach and decision-making. For patients vaccinated with potentially-compromised vaccines, serological testing should be considered prior to revaccination. Revaccination may not be the most appropriate course of action for all patients.

Systematic review protocol on Bacillus Calmette-Guerin (BCG) revaccination and protection against tuberculosis

INTRODUCTION

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis (M.TB) and other species of the Mycobacterium tuberculosis complex. Globally, TB is ranked as the ninth leading cause of death and the leading cause of death from a single infectious agent. The bacille Calmette-Guerin (BCG) vaccine has been used globally since 1921 for the prevention of TB in humans, and was derived from an attenuated strain of Mycobacterium bovis. Evidence from previous randomised trials show that the efficacy of primary BCG vaccination against pulmonary TB ranged from no protection to very high protection. In addition, some studies suggest a benefit of BCG revaccination. For example, a recent trial conducted in South Africa showed that BCG revaccination of adolescents could reduce the risk of TB infection by half. However, we are not aware of any recent systematic reviews of the effects of BCG revaccination. Thus, the need for this systematic review of the effects of BCG revaccination on protection against TB infection and disease.

METHOD AND ANALYSIS

We will search PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, WHO International Clinical Trials Registry Platform and reference lists of relevant publications for potentially eligible studies. We will screen search outputs, select eligible studies, extract data and assess risk of bias in duplicate. Discrepancies will be resolved by discussion and consensus or arbitration. We will use the Grading of Recommendations Assessment, Development and Evaluation method to assess the certainty of the evidence. The planned systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) in August 2018.

ETHICS AND DISSEMINATION

Publicly available data will be used, hence no formal ethical approval will be required for this review. The findings of the review will be disseminated through conference presentations and publication in an open-access peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42018105916.

Improved Antibody Response to Three Additional Hepatitis B Vaccine Doses Following Primary Vaccination Failure in Patients with Inflammatory Bowel Disease

BACKGROUND

Studies have shown the efficacy of hepatitis B (HBV) vaccination in patients with inflammatory bowel disease (IBD) is impaired, but few data exist regarding the effectiveness of revaccination strategies following primary vaccination failure. Our aim was to analyze the association between administration of additional vaccine doses and hepatitis B surface antibody (HBsAb) seroconversion.

METHODS

This is a retrospective cohort study. Inclusion criteria are as follows: age ≥ 18, diagnosis of Crohn's disease (CD) or ulcerative colitis (UC), inadequate HBsAb < 10 IU/L following initial HBV vaccination series, subsequent administration of 1-3 additional doses of HBV vaccine with follow-up serum HBsAb measurements. Patients were stratified into groups of ≤ 2 or 3 doses received. Primary outcome was achieving HBsAb > 10 IU/L. Outcomes were stratified by age ≥ or < 40 years. We performed logistic and linear multivariable regression analyses for categorical and continuous data.

RESULTS

The study cohort consists of (n = 149) 54.4% women; 77.9% white; 72.6% with CD, with mean age: 46.2. Patients of all ages and age ≥ 40 years, who received 3 additional doses of vaccine, were more likely to achieve seroprotective HBsAb levels than patients who received 1 or 2 doses (OR 1.77, P = 0.01; OR 1.9, P = 0.03, respectively, after adjusting for age, sex, race, immunosuppressive medication exposure, time between vaccine/titer).

CONCLUSIONS

Following initial HBV vaccination failure, patients with IBD of all ages are more likely to develop seroprotective levels of HBsAb following 3 additional vaccine doses, rather than 1 or 2 alone. In patients who fail primary HBV vaccination, providers should consider a more aggressive revaccination strategy with an additional 3-dose series.

Initial vaccination and revaccination with Type I PRRS 94881 MLV reduces viral load and infection with porcine reproductive and respiratory syndrome virus

Background

Porcine reproductive and respiratory syndrome (PRRS) causes respiratory distress in pigs, reproductive failure in breeding-age gilts and sows, and can have devastating economic consequences in domestic herds. Several PRRS vaccines are available commercially. This study compared the effectiveness of single-vaccination and revaccination schedules using the PRRS 94881 Type I modified live virus (MLV) vaccine ReproCyc® PRRS EU with no vaccination (challenge control) in protecting against a PRRS virus (PRRSV) challenge in non-pregnant gilts.

Results

Data were available from 48 gilts across three groups: a challenge control group (n = 16), which received no vaccination; a revaccination group (n = 16), which received ReproCyc® PRRS EU on Days 0 and 56; and a single vaccination group (n = 16), which received ReproCyc® PRRS EU on Day 56. All gilts were PRRSV RNA-negative (based on reverse transcription and quantitative polymerase chain reaction [RT-qPCR]) and PRRSV seronegative (based on enzyme-linked immunosorbent assay [ELISA]) at Day 0. All gilts were challenged with PRRSV strain 190136 on Day 91.

Viral RNA loads in both vaccination groups were significantly reduced compared with the challenge control group on Days 98 (P < 0.0001) and 101 (P < 0.0001), indicating that vaccinated gilts were better able to respond to challenge than unvaccinated gilts. At all timepoints following challenge, mean viral RNA load and the percentage of PRRSV RNA-positive gilts were numerically higher in the single-vaccination group than in the revaccination group; these differences were statistically significant on Day 101 (P = 0.0434). Furthermore, viremia levels after challenge were significantly lower in the revaccination group than in the single-vaccination group based on median area under the curve (AUC) values for viral RNA load from Day 91 to Day 112, suggesting that revaccinated gilts had better protection from viral infection than gilts who received a single vaccination. Protection from viremia did not correlate with the proportion of seropositive gilts on Day 91. In the single-vaccination group, 94% of pigs were seropositive on Day 91 compared with 56% in the revaccination group. Vaccination was well tolerated and no safety concerns were identified.

Conclusions

Both single-vaccination and revaccination with ReproCyc® PRRS EU were effective in reducing PRRSV viremia post-challenge. These findings have important implications for herd management as both the single-vaccination and revaccination schedules protect against PRRSV challenge, with revaccination appearing to provide better protection from viremia than single vaccination.

Revaccination with Live Attenuated Vaccines Confer Additional Beneficial Nonspecific Effects on Overall Survival: A Review

BACKGROUND

Live vaccines against measles (MV), tuberculosis (BCG), polio (OPV) and smallpox reduce mortality more than explained by target-disease prevention. The beneficial nonspecific effects (NSEs) of MV are strongest when MV is given in presence of maternal antibodies. We therefore hypothesised that revaccination in presence of prior immunity enhances beneficial NSEs.

METHODS

Literature search for studies of revaccination and mortality.

FINDINGS

In two randomised trials (RCTs), two doses versus one dose of MV reduced all-cause mortality by 63% (95% CI: 23-83%) from 9 to 18months of age. In a quasi-experimental study two doses before and after 9months compared with one dose of MV after 9months of age reduced mortality by 59% (25-81%). BCG-revaccination significantly enhanced BCG's effect against overall child mortality in two RCTs. In a natural experiment study of OPV campaigns over a 13-year-period in Guinea-Bissau, each additional dose of OPV was associated with a 13% (4-21%) reduction in mortality rate. The beneficial NSEs of smallpox vaccination for survival increased significantly with the number of smallpox vaccination scars.

INTERPRETATION

Revaccination with live vaccines led to substantial reductions in overall mortality. These findings challenge current understanding of vaccines and may explain the beneficial effects of campaigns with live vaccines.

Revaccination with 23-valent pneumococcal polysaccharide vaccine in the Japanese elderly is well tolerated and elicits immune responses

BACKGROUND

Following primary vaccination of adults ⩾65years of age with 23-valent pneumococcal polysaccharide vaccine (PPSV23), immune responses increase and thereafter appear to decrease over time. With increased life expectancy worldwide, revaccination with PPSV23 may be required for continued protection of the elderly population against pneumococcal disease. The present study evaluated the immunogenicity and safety of revaccination with PPSV23 in the Japanese elderly.

METHODS

Depending on prior history of PPSV23 vaccination, adults aged ⩾70years were given a first dose (primary group; N=81) or second dose (revaccination group; N=161, at least 5years after first dose) of PPSV23 intramuscularly. Subjects were matched for gender, age, and number and type of comorbidity across both groups. Blood samples were collected before and 4weeks postvaccination to measure serotype-specific immunoglobulin G (IgG) concentrations and opsonophagocytic killing activity (OPA) antibody titers to serotypes included in the vaccine. Injection-site and systemic adverse events (AEs) were collected for 14days postvaccination.

RESULTS

Baseline serotype-specific IgG geometric mean concentrations (GMCs) and OPA geometric mean titers (GMTs) were generally higher in subjects with a prior history of PPSV23 vaccination than in PPSV23-naïve subjects. The levels of IgG GMCs and OPA GMTs after revaccination were generally comparable to those observed after primary vaccination. Incidences of systemic AEs were comparable between the 2 groups. Although incidences of injection-site AEs were higher following revaccination than primary vaccination, the difference was not clinically significant as most AEs were mild to moderate in intensity and resolved within 5days after revaccination without treatment.

CONCLUSION

Revaccination with PPSV23 was well tolerated and associated with increases in serotype-specific IgG concentrations and OPA titers in the elderly who received a prior PPSV23 dose at least 5years before. Revaccination with PPSV23 can be safely implemented in the elderly for continued prevention against pneumococcal disease.

CLINICAL TRIAL REGISTRY NUMBER

NCT02260882.

Immunogenicity and safety of a second administration of 13-valent pneumococcal conjugate vaccine 5 years after initial vaccination in adults 50 years and older

BACKGROUND

Vaccination effectively reduces invasive disease and pneumonia caused by Streptococcus pneumoniae. However, waning antibody titers and the ability of revaccination to boost titers in older adults have been concerns. A study to describe antibody persistence after vaccination with 13-valent pneumococcal conjugate vaccine (PCV13) and response to revaccination 5 years after the initial dose was conducted.

METHODS

Pneumococcal vaccine-naive subjects aged 50-59 years were randomized and vaccinated with PCV13 plus trivalent inactivated influenza vaccine concomitantly or 1 month apart, then revaccinated with PCV13 five years later. Antipneumococcal polysaccharide opsonophagocytic activity (OPA) geometric mean titers (GMTs) and immunoglobulin G (IgG) geometric mean concentrations (GMCs) were determined before and approximately 1 month after each vaccination. Targeted local reactions and systemic events were collected for 14 days, adverse events (AEs) for 1 month, and serious AEs (SAEs) for 6 months after each vaccination.

RESULTS

Of 1116 randomized subjects, 727 were revaccinated at year 5. Between the time of initial vaccination and revaccination, OPA GMTs and IgG GMCs declined but remained higher than levels before initial vaccination for 12 of the 13 vaccine serotypes. One month after revaccination, OPA GMTs and IgG GMCs were comparable with, or higher than, levels observed 1 month after initial vaccination for most vaccine serotypes. Local reactions were mostly mild. AEs were reported by <5% and SAEs by <1% of subjects at 1 and 6 months after revaccination, respectively. No SAEs were vaccine-related.

CONCLUSIONS

Revaccination of adults ≥50 years with PCV13 five years after primary vaccination was safe and immunogenic. Additionally, antibody titers were maintained for at least 5 years after vaccination. The vaccine stimulated a memory response as shown by enhanced responses that were maintained or enhanced by revaccination. CLINICALTRIALS.

GOV REGISTRATION

NCT00521586.

Induction of systemic and mucosal immunity and maintenance of its memory against influenza A virus by nasal vaccination using a new mucosal adjuvant SF-10 derived from pulmonary surfactant in young cynomolgus monkeys

Induction of systemic and mucosal immunity and maintenance of its memory was investigated in 12 young male cynomolgus monkeys after intranasal instillation of flu vaccine using a new mucosal adjuvant SF-10 derived from pulmonary surfactant constituents. Split-product of influenza virus A/California/7/2009(H1N1)pdm hemagglutinin vaccine (HAv) at 15 μg with or without SF-10 and the adjuvant alone were instilled intranasally three times every 2 weeks. SF-10-adjuvanted HAv (SF-10-HAv) elicited significantly higher HAv-specific IgG and hemagglutinin inhibition (HI) titers in serum and HAv-specific secretory IgA and its neutralizing activities in nasal washes compared with HAv antigen and SF-10 alone. Significant cross-neutralizing activities of nasal washes after the third vaccination to several other H1N1 and H3N2 strains were observed. HI titers in serum and neutralizing activities in nasal washes reached peak levels at 6 weeks after initial vaccination, then gradually decreased after 10 weeks and returned to the baseline levels at 36 weeks. A single intranasal revaccination of SF-10-HAv at 36 weeks rapidly and significantly increased both immunity in serum and nasal washes compared with naïve monkeys. Revaccination by one or two doses achieved almost maximal immunity at 2 or 4 weeks after instillation. Statistically significant adverse effects (e.g., body weight loss, elevated body temperature, nasal discharge, change in peripheral blood leukocyte and platelet counts) were not observed for 2 weeks after vaccination of SF-10-HAv, HAv or SF-10 and also during the experimental period. These results in young monkey model suggest the potential of clinical use SF-10 for intranasal flu vaccine.

Use of the nonavalent HPV vaccine in individuals previously fully or partially vaccinated with bivalent or quadrivalent HPV vaccines

With the availability of the nonavalent human papillomavirus (HPV) vaccine, vaccinees, parents and healthcare providers need guidance on how to complete an immunization course started with the bi- or quadrivalent vaccine and whether to revaccinate individuals who have completed a full immunization course with the bi- or quadrivalent vaccine. To answer these questions three parameters should be considered: age at the start of vaccination (9 to 14 years of age versus 15 years and older, the cut-off for 2 or 3 doses schedule), the number of doses already received and the time interval between doses. Based on a number of scenarios, we propose that the 9-valent vaccine can be used to complete an incomplete vaccination regimen or might be added to a previous completed schedule to extend protection.

Kinetics of rabies antibodies as a strategy for canine active immunization

Background

Rabies, a zoonosis found throughout the globe, is caused by a virus of the Lyssavirus genus. The disease is transmitted to humans through the inoculation of the virus present in the saliva of infected mammals. Since its prognosis is usually fatal for humans, nationwide public campaigns to vaccinate dogs and cats against rabies aim to break the epidemiological link between the virus and its reservoirs in Brazil.

Findings

During 12 months we evaluated the active immunity of dogs first vaccinated (booster shot at 30 days after first vaccination) against rabies using the Fuenzalida-Palácios modified vaccine in the urban area of Botucatu city, São Pauto state, Brazil. Of the analyzed dogs, 54.7% maintained protective titers (≥0.5 IU/mL) for 360 days after the first vaccination whereas 51.5% during all the study period.

Conclusions

The present results suggest a new vaccination schedule for dogs that have never been vaccinated. In addition to the first dose of vaccine, two others are recommended: the second at 30 days after the first and the third dose at 180 days after the first for the maintenance of protective titers during 12 months.

Safety and reactogenicity of BCG revaccination with isoniazid pretreatment in TST positive adults

RATIONALE

Global tuberculosis (TB) control may require mass vaccination with a new TB vaccine, such as a recombinant bacille Calmette Guerin (BCG) or attenuated Mycobacterium tuberculosis (MTB). The safety profile of live mycobacterial vaccines in latently infected adults with prior infant BCG vaccination is unknown.

OBJECTIVES

Evaluate safety and reactogenicity of BCG revaccination, with or without isoniazid (INH) pretreatment, in adults with latent MTB infection (LTBI).

METHODS

Eighty-two healthy, HIV uninfected, South African adults, with a BCG scar and tuberculin skin test (TST) diameter ≥ 15 mm, were randomized to receive 6 months of INH, starting either before, or 6 months after, intradermal revaccination with BCG Vaccine SSI (Statens Serum Institut, Copenhagen). Safety and reactogenicity data are reported through 3 months post BCG revaccination.

RESULTS

Baseline characteristics were similar between treatment arms. Mean baseline TST diameter was 20 ± 4 mm. Seventy-two subjects received BCG revaccination. Injection site erythema (68%) and induration (86%) peaked 1 week after revaccination. Ulceration (76%) peaked at 2 weeks, and resolved by 3 months in all but 3 subjects. Diameter of ulceration was >10mm in only 8%, but a residual scar was common (85%). No regional lymphadenitis or serious morbidity related to BCG was seen. Reactogenicity was not affected by INH pretreatment.

CONCLUSION

BCG revaccination of MTB infected adults is safe, well tolerated, and reactogenicity is similar to that of primary BCG vaccination. Clinical trials of live recombinant BCG or attenuated MTB vaccines may be considered in latently infected adults, with or without INH pretreatment (ClinicalTrials.gov identifier: NCT01119521).

Sustained functional serotype-specific antibody after primary and secondary vaccinations with a pneumococcal polysaccharide vaccine in elderly patients with chronic lung disease

An observational study was conducted to determine immunogenicity before and after primary and secondary vaccinations with 23-valent pneumococcal polysaccharide vaccine in a cohort of 40 elderly patients with chronic lung diseases. Safety of this vaccine was also compared between primary and secondary vaccination. We analyzed serotype-specific immunoglobulin G (IgG) and the opsonization index (OI) for serotypes 6B, 14, 19F, and 23F and compared adverse local and systemic reactions. The levels of serotype-specific IgG and the OIs significantly increased 1 month after primary and secondary vaccinations. Peak levels of IgG after secondary vaccination were 5-20% lower than those after primary vaccination, while serotype-specific OIs after secondary vaccination were comparable with those after primary vaccination. The levels of serotype-specific IgG required for 50% killing significantly decreased 1 month after vaccination. These values for serotypes 14, 19F, and 23F were slightly elevated immediately before secondary vaccination, but those for serotype 6B did not change. After secondary vaccination, these values declined slightly for serotypes 14, 19F, and 23F and remained low for serotype 6B. Although self-limited local and systemic reactions were more frequent after secondary vaccination compared with primary vaccination, no serious systemic reaction was found after either vaccination. Our data suggest a sustained functional serotype-specific IgG after primary and secondary vaccination and confirmed the safety of secondary vaccination among elderly individuals with chronic lung disease.