New Insights on Respiratory Syncytial Virus Prevention.

Respiratory syncytial virus (RSV) is a well-known infant pathogen transmitted mainly by droplets. It is a leading cause of upper respiratory tract infections in children, usually with a mild course of illness. RSV has also been a threat to older people, especially those with underlying medical conditions. For a long time, prevention was limited to passive immunoprophylaxis with palivizumab for high-risk infants. There was a strong need to find other treatment or prevention methods against RSV infections. In addition, after the coronavirus disease 2019 (COVID-19) pandemic, some significant changes in RSV epidemiology have been observed. Researchers noticed the shift in RSV seasonality and age distribution and the increased number of cases in older infants and adults. All of these made the need to find other medical options even stronger. Fortunately, two protein-based vaccines against RSV have successfully passed all phases of clinical trials and have been approved for use by adults and older people. One of them is also approved for infants from birth to 6 months of age (after maternal immunisation during pregnancy) and for pregnant women between 24 and 36 weeks of pregnancy. Also, a new passive immunisation option named nirsevimab (a highly potent monoclonal antibody with a long half-life) is now available for the paediatric group. In this review, we will discuss the previous and current RSV prevention methods in the light of structural discoveries of RSV antigens.

Rotavirus Vaccination of Premature Newborns in the NICU: Evaluation of Vaccination Rates and Safety Based on a Single-Centre Study.

Preterm newborns are babies born before the end of the 36th week of gestational life. They are at increased risk of infection and death from infectious diseases. This is due, among other things, to the immaturity of the immune system and the long hospitalisation period. One common infectious disease in the paediatric population is rotavirus (RV) infection. We now have specific vaccines against this pathogen. The aim of this study was to evaluate the safety of rotavirus vaccination in the neonatal intensive care unit (NICU) setting and to determine the tolerance of this vaccine in low- and extremely low-weight children. The study carried out at a single centre, the University Hospital in Kraków, also allowed the assessment of vaccination trends during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. During the observation period, 126 premature newborns received the RV vaccine. We observed no adverse effects, and our analysis shows safety and good tolerance of the vaccine among preterm babies. In addition, we observed an increase in vaccination rates between 2019 and 2021, partly explained by parents' anxiety about infectious diseases in the era of pandemics and partly explained by a change in vaccination policy in Poland and the introduction of refunding for RV vaccination.

Immunogenicity and safety of a pentavalent meningococcal ABCWY vaccine in adolescents and young adults: an observer-blind, active-controlled, randomised trial.

BACKGROUND: Meningococcal serogroups A, B, C, W, and Y cause nearly all meningococcal disease, and comprehensive protection requires vaccination against all five serogroups. We aimed to assess the immunogenicity and safety of a pentavalent MenABCWY vaccine comprising two licensed vaccines-meningococcal serogroup B-factor H binding protein vaccine (MenB-FHbp) and a quadrivalent meningococcal serogroup ACWY tetanus toxoid conjugate vaccine (MenACWY-TT)-compared with two doses of MenB-FHbp and a single dose of quadrivalent meningococcal serogroup ACWY CRM197-conjugate vaccine (MenACWY-CRM) as the active control. We previously reported the primary safety and immunogenicity data relating to the two-dose MenB-FHbp schedule. Here we report secondary outcomes and ad-hoc analyses relating to MenABCWY immunogenicity and safety. METHODS: We did an observer-blind, active-controlled trial at 68 sites in the USA, Czech Republic, Finland, and Poland. Healthy individuals (aged 10-25 years) who had or had not previously received a MenACWY vaccine were randomly assigned (1:2) using an interactive voice or web-based response system, stratified by previous receipt of a MenACWY vaccine, to receive 0·5 mL of MenABCWY (months 0 and 6) and placebo (month 0) or MenB-FHbp (months 0 and 6) and MenACWY-CRM (month 0) via intramuscular injection into the upper deltoid. All individuals were masked to group allocation, except staff involved in vaccine dispensation, preparation, and administration; and protocol adherence. Endpoints for serogroups A, C, W, and Y included the proportion of participants who achieved at least a four-fold increase in serum bactericidal antibody using human complement (hSBA) titres between baseline and 1 month after each vaccination. For serogroup B, secondary endpoints included the proportion of participants who achieved at least a four-fold increase in hSBA titres from baseline for each of four primary test strains and the proportion of participants who achieved titres of at least the lower limit of quantitation against all four test strains combined at 1 month after the second dose. Endpoints for serogroups A, C, W, and Y were assessed in the modified intent-to-treat (mITT) population, which included all randomly assigned participants who received at least one vaccine dose and had at least one valid and determinate MenB or serogroup A, C, W, or Y assay result before vaccination up to 1 month after the second dose, assessed in ACWY-experienced and ACWY-naive participants separately. Secondary endpoints for serogroup B were analysed in the evaluable immunogenicity population, which included all participants in the mITT population who were randomly assigned to the group of interest, received all investigational products as randomly assigned, had blood drawn for assay testing within the required time frames, had at least one valid and determinate MenB assay result after the second vaccination, and had no important protocol deviations; outcomes were assessed in both ACWY-experienced and ACWY-naive populations combined. Non-inferiority of MenABCWY to MenACWY-CRM and MenB-FHbp was determined using a -10% non-inferiority margin for these endpoints. Reactogenicity and adverse events were assessed among all participants who received at least one vaccine dose and who had available safety data. This trial is registered with Clinicaltrials.gov, NCT03135834, and is complete. FINDINGS: Between April 24 and November 10, 2017, 1610 participants (809 MenACWY-naive; 801 MenACWY-experienced) were randomly assigned: 544 to receive MenABCWY and placebo (n=272 MenACWY-naive; n=272 MenACWY-experienced) and 1066 to receive MenB-FHbp and MenACWY-CRM (n=537 MenACWY-naive; n=529 MenACWY-experienced). Among MenACWY-naive or MenACWY-experienced MenABCWY recipients, 75·5% (95% CI 69·8-80·6; 194 of 257; serogroup C) to 96·9% (94·1-98·7; 254 of 262; serogroup A) and 93·0% (88·4-96·2; 174 of 187; serogroup Y) to 97·4% (94·4-99·0; 224 of 230; serogroup W) achieved at least four-fold increases in hSBA titres against serogroups ACWY after dose 1 or 2, respectively, in ad-hoc analyses. Additionally, 75·8% (71·5-79·8; 320 of 422) to 94·7% (92·1-96·7; 396 of 418) of MenABCWY and 67·4% (64·1-70·6; 563 of 835) to 95·0% (93·3-96·4; 782 of 823) of MenB-FHbp recipients achieved at least four-fold increases in hSBA titres against MenB strains after dose 2 in secondary analyses; 79·9% (334 of 418; 75·7-83·6) and 74·3% (71·2-77·3; 605 of 814), respectively, achieved composite responses. MenABCWY was non-inferior to MenACWY-CRM (single dose) and to MenB-FHbp in ad-hoc analyses based on the proportion of participants with at least a four-fold increase in hSBA titres from baseline and (for MenB-FHbp only) composite responses. Reactogenicity events after vaccination were similarly frequent across groups, were mostly mild or moderate, and were unaffected by MenACWY experience. No adverse events causing withdrawals were related to the investigational product. Serious adverse events were reported in four (1·5%; 0·4-3·7) MenACWY-naive individuals in the MenABCWY group versus six (2·2%; 0·8-4·8) among MenACWY-experienced individuals in the MenABCWY group and 14 (1·3%; 0·7-2·2) in the active control group (MenACWY-experienced and MenACWY-naive individuals combined); none of these were considered related to the investigational product. INTERPRETATION: MenABCWY immune responses were robust and non-inferior to MenACWY-CRM and MenB-FHbp administered separately, and MenABCWY was well tolerated. The favourable benefit-risk profile supports further MenABCWY evaluation as a simplified schedule compared with current adolescent meningococcal vaccination programmes. FUNDING: Pfizer.

Trained Immunity, BCG and SARS-CoV-2 General Outline and Possible Management in COVID-19.

The Bacillus Calmette-Guérin (BCG) vaccine has been in use for over 100 years. It protects against severe, blood-borne forms of tuberculosis. Observations indicate that it also increases immunity against other diseases. The mechanism responsible for this is trained immunity, an increased response of non-specific immune cells in repeated contact with a pathogen, not necessarily of the same species. In the following review, we present the current state of knowledge on the molecular mechanisms responsible for this process. We also seek to identify the challenges facing science in this area and consider the application of this phenomenon in managing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic.

Evaluation of BNT162b2 Covid-19 Vaccine in Children Younger than 5 Years of Age.

BACKGROUND: Safe and effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in young children. METHODS: We conducted a phase 1 dose-finding study and are conducting an ongoing phase 2-3 safety, immunogenicity, and efficacy trial of the BNT162b2 vaccine in healthy children 6 months to 11 years of age. We present results for children 6 months to less than 2 years of age and those 2 to 4 years of age through the data-cutoff dates (April 29, 2022, for safety and immunogenicity and June 17, 2022, for efficacy). In the phase 2-3 trial, participants were randomly assigned (in a 2:1 ratio) to receive two 3-µg doses of BNT162b2 or placebo. On the basis of preliminary immunogenicity results, a third 3-µg dose (≥8 weeks after dose 2) was administered starting in January 2022, which coincided with the emergence of the B.1.1.529 (omicron) variant. Immune responses at 1 month after doses 2 and 3 in children 6 months to less than 2 years of age and those 2 to 4 years of age were immunologically bridged to responses after dose 2 in persons 16 to 25 years of age who received 30 µg of BNT162b2 in the pivotal trial. RESULTS: During the phase 1 dose-finding study, two doses of BNT162b2 were administered 21 days apart to 16 children 6 months to less than 2 years of age (3-µg dose) and 48 children 2 to 4 years of age (3-µg or 10-µg dose). The 3-µg dose level was selected for the phase 2-3 trial; 1178 children 6 months to less than 2 years of age and 1835 children 2 to 4 years of age received BNT162b2, and 598 and 915, respectively, received placebo. Immunobridging success criteria for the geometric mean ratio and seroresponse at 1 month after dose 3 were met in both age groups. BNT162b2 reactogenicity events were mostly mild to moderate, with no grade 4 events. Low, similar incidences of fever were reported after receipt of BNT162b2 (7% among children 6 months to <2 years of age and 5% among those 2 to 4 years of age) and placebo (6 to 7% among children 6 months to <2 years of age and 4 to 5% among those 2 to 4 years of age). The observed overall vaccine efficacy against symptomatic Covid-19 in children 6 months to 4 years of age was 73.2% (95% confidence interval, 43.8 to 87.6) from 7 days after dose 3 (on the basis of 34 cases). CONCLUSIONS: A three-dose primary series of 3-µg BNT162b2 was safe, immunogenic, and efficacious in children 6 months to 4 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

Newborn screening and gene therapy in SMA: Challenges related to vaccinations.

Spinal muscular atrophy (SMA) affects one in 7,500-10,000 newborns. Before the era of disease-modifying therapies, it used to be the major genetic cause of mortality in infants. Currently, there are three therapies approved for SMA, including two molecules modifying the splicing of the SMN2 gene and one gene therapy providing a healthy copy of the SMN gene with a viral vector. The best effects of any of these therapies are achieved when the treatment is administered in the presymptomatic stage of the disease, therefore newborn screening programs are being introduced in many countries. Patients identified in newborn screening might be eligible for gene therapy. However, gene therapy and the associated administration of steroids in newborns might interfere with the vaccination schedule, which includes live immunization against tuberculosis in some countries. The timing of gene therapy in patients who received live vaccinations has not yet been addressed neither in the clinical trials nor in the existing international guidelines. The Polish Vaccinology Association has developed the first recommendations for gene therapy administration in newborns who received live vaccination against tuberculosis. Their statement was implemented in the current guidelines for Polish SMA patients identified in the newborn screening program and might be helpful for medical professionals in other countries where live vaccine against tuberculosis is still in routine use in newborns.

A Multi-Center, Randomised, Double-Blind, Placebo-Controlled Phase III Clinical Trial Evaluating the Impact of BCG Re-Vaccination on the Incidence and Severity of SARS-CoV-2 Infections among Symptomatic Healthcare Professionals during the COVID-19 Pandemic in Poland-First Results.

Tuberculosis vaccines (Bacillus Calmette-Guérin, BCG) were introduced 100 years ago and are still recommended by the World Health Organization to prevent the disease. Studies have shown that BCG vaccination can stimulate non-specific immune responses and reduce the incidence of certain diseases. At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, it was hypothesised that the incidence of COVID-19 was lower in countries with BCG prevention. In an attempt to verify this thesis, we conducted a multicenter, randomised, double-blind, placebo-controlled study on a group of 695 health care workers aged 25 years and over in Poland. All participants in the study had a tuberculin test, after which those who were negative were randomised (1:1) and received either the BCG- or placebo vaccine. From then on, these people were subjected to three months of observation for the occurrence of COVID-19 symptoms. The statistical analysis did not reveal any significant correlation between the frequency of incidents suspected of COVID-19 and BCG-10 vaccination, the result of the tuberculin test and the number of scars. The only statistically significant feature was the type of medical profession-nurses became infected more often than doctors or other medical workers (p = 0.02). The results differ from similar trials in other countries. Perhaps this is due to the lack of an unvaccinated control group. The impact of BCG vaccination on the course of COVID-19 requires further research.

A phase 3 study to assess the immunogenicity, safety, and tolerability of MenB-FHbp administered as a 2-dose schedule in adolescents and young adults.

BACKGROUND: The MenB-FHbp vaccine is licensed to prevent meningococcal serogroup B disease on either a 2-dose (0, 6 months) or 3-dose (0, 1-2, 6 months) series. This phase 3 study further assessed the immunogenicity and safety of the 2-dose MenB-FHbp schedule. METHODS: Subjects 10-25 years of age received MenB-FHbp (months 0, 6) and the quadrivalent meningococcal conjugate vaccine MenACWY-CRM (month 0). Primary immunogenicity endpoints included percentages of subjects achieving ≥ 4-fold increases from baseline in serum bactericidal antibody using human complement (hSBA) titers for 4 diverse, vaccine-heterologous primary serogroup B test strains and titers ≥ lower limit of quantitation (LLOQ; 1:8 or 1:16) for all 4 primary strains combined (composite response) after dose 2; a titer ≥ 1:4 is the accepted correlate of protection. Percentages of participants with hSBA titers ≥ LLOQ for 10 additional vaccine-heterologous strains were also assessed; positive predictive values of primary strain responses for secondary strain responses were determined. Safety was assessed. RESULTS: Overall, 1057 subjects received dose 1 and 946 received dose 2 of MenB-FHbp. Percentages of participants achieving ≥ 4-fold increases in hSBA titers against each primary strain after dose 2 ranged from 67.4% to 95.0% and the composite response was 74.3%. Primary strain responses were highly predictive of secondary strain responses. Most reactogenicity events were mild-to-moderate in severity and did not lead to withdrawal from the study. Adverse events (AEs) considered by the investigator to be related to vaccination occurred in 4.2% (44/1057) of subjects, and there were no serious AEs or newly diagnosed chronic medical conditions considered related to vaccination. CONCLUSIONS: MenB-FHbp administered at 0, 6 months was well tolerated and induced protective bactericidal antibody responses against diverse serogroup B strains. Findings provide further support for the continued use of MenB-FHbp on a 2-dose schedule in this population.

A Multi-Centre, Randomised, Double-Blind, Placebo-Controlled Phase III Clinical Trial Evaluating the Impact of BCG Re-Vaccination on the Incidence and Severity of SARS-CoV-2 Infections among Symptomatic Healthcare Professionals during the COVID-19 Pandemic in Poland-Evaluation of Antibody Concentrations.

Tuberculosis (TB) was the predominant cause of death from a single infectious agent worldwide before the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic. Although TB vaccines have been successfully used for about 100 years, their full effect is still unknown. In previous studies, a reduced incidence and mortality from a coronavirus disease in TB-vaccinated populations were reported. In this article, we present the secondary analysis of a randomised controlled trial, reporting the results of a serological assessment evaluating the effect of the Bacillus Calmette-Guérin (BCG) vaccine on SARS-CoV-2. Participants-healthcare workers-were assessed 1-2 and 8 months after the second dose of the coronavirus disease 2019 (COVID-19) vaccine. We found no associations between antibody concentration, BCG revaccination, and additional characteristics, such as age, gender, or Body Mass Index. The effect of BCG vaccination on the immunological response against SARS-CoV-2 requires further research.

Ten-year follow-up on efficacy, immunogenicity and safety of two doses of a combined measles-mumps-rubella-varicella vaccine or one dose of monovalent varicella vaccine: Results from five East European countries.

BACKGROUND: We assessed the 10-year efficacy, immunogenicity and safety of two doses of a combined measles-mumps-rubella-varicella vaccine (MMRV) or one dose of a monovalent varicella vaccine (V) in children from Czech Republic, Lithuania, Poland, Romania and Slovakia. METHODS: This was a phase IIIB follow-up of an observer-blind, randomized, controlled trial (NCT00226499). In phase A, healthy children aged 12-22 months from 10 European countries were randomized in a 3:3:1 ratio to receive two doses of MMRV (MMRV group), one dose of MMR followed by one dose of V (MMR + V group), or two doses of MMR (MMR; control group), 42 days apart. Vaccine efficacy (VE) against varicella (confirmed by viral DNA detection or epidemiological link and clinical assessment) was calculated with 95% confidence intervals using Cox proportional hazards regression model. Immunogenicity was assessed as seropositivity rates and geometric mean concentrations (GMCs). Solicited and unsolicited adverse events (AEs) and serious AEs (SAEs) were recorded. RESULTS: A total of 3705 children were vaccinated (1590, MMRV group; 1586, MMR + V group; 529, MMR group). There were 663 confirmed varicella cases (47, MMRV group; 349, MMR + V group; 267, MMR group). VE ranged between 95.4% (Lithuania) and 97.4% (Slovakia) in the MMRV group and between 59.3% (Lithuania) and 74% (Slovakia) in the MMR + V group. At year 10, seropositivity rates were 99.5%-100% in the MMRV group, 98%-100% in the MMR + V group and 50%-100% in the MMR control group, and the anti-VZV antibody GMCs were comparable between MMRV and MMR + V groups. The occurrence of solicited and unsolicited AEs was similar across groups and no SAE was considered as vaccination-related. No new safety concerns were identified. CONCLUSIONS: Our results indicated that two doses of varicella zoster virus-containing vaccine provided better protection than one dose against varicella and induced antibody responses that persisted 10 years post-vaccination.

Who or What Influences the Individuals' Decision-Making Process Regarding Vaccinations?

Thanks to vaccines, many people are not exposed to the risks associated with vaccine-preventable diseases (VPDs). This, however, results in growing popularity of antivaccine movements and affects global and local epidemiological situation. Vaccine hesitancy has become a significant problem not only for epidemiologists but also for practitioners. Fortunately, the hesitant group seems to be vulnerable to intervention, and studies indicate that these patients can be persuaded to undergo vaccinations. The aim of the present study was to determine the factors most strongly affecting vaccination-related attitudes and decisions. An anonymous, self-administered survey consisting of demographic data and single select multiple-choice questions regarding vaccination was conducted. The voluntary study included secondary school pupils, medical and nonmedical students, healthcare professionals, hospital and clinic patients as well as parents. A total of 7950 survey forms were distributed between January 2018 and June 2019 in south-eastern Poland. A total of 6432 respondents (80.2%) completed a questionnaire that was eligible for analysis. The positive attitude toward vaccination was significantly affected by older age, by the fact of obtaining information on vaccinations from a physician, this information's higher quality (assessed in school grade scale), higher level of knowledge on vaccines and by the fact of denying the association between vaccination and autism in children (p < 0.001). The probability of supporting vaccinations was almost eight-fold lower among respondents believing the vaccine-autism relationship. Chance of supporting vaccination doubled in the group with a higher knowledge level. The individuals not provided with expert information on vaccination were twice as often unconvinced. Age, education and having children significantly affected the attitude toward influenza immunization (p < 0.001). Older, better educated respondents and those having children were more positive about vaccinations. The medical community still exert decisive effects on attitudes toward vaccinations. High-quality information provided by them is of great importance. Skillful and competent provision of evidence-based information disproving the myth about vaccine-autism connection and proper education of medical staff is essential in molding positive attitudes toward vaccinations.

Vaccination Against Measles, Mumps, and Rubella in the Light of Current Epidemic Threats: Unjustified Postponement.

A worrying increase in the number of measles cases has been noted recently in Poland, which may have to do with a decreasing proportion of children vaccinated against measles, mumps, and rubella (MMR) in the second year of life (<95%). For many years, MMR vaccination in children has been associated with a fear of allergy to eggs. This study seeks to define the reason and justification for postponing MMR vaccination in a population of children referred to the outpatient specialist immunization clinic. One hundred and thirty eight (138) children, mean 24.5 ± 26.6 months, with a history of past allergies, in whom the first-time MMR vaccination was delayed by family doctors for fear of allergic reactions, were enrolled into the study. The mean delay in a vaccine shot was 12.3 ± 26.9 months. There were 101 children who displayed a distinct allergy to the egg proteins, among other accompanying types of allergy. All of the 138 children were found eligible to receive MMR vaccine at the visit to the clinic. No early allergic responses were noticed in any of the children. There were negligible delayed allergic responses in six children, all from the egg allergy group. We conclude that MMR vaccination in children with egg allergy is safe and can be conducted on the outpatient basis without any specific precautions or safety measures. Delays in vaccination were unjustified and may jeopardize children's health. There is a need for insightful education of primary care doctors concerning of MMR vaccination safety, particularly when allergy is suspected, to avoid unduly and potentially harmful delays.

[Why are preventive vaccinations still required?]

Vaccinations in Poland and other industrialized countries have been in the firing line for more than two decades. Members of the "anti-vaccine movement" and alternative medicine supporters are openly reluctant to this form of preventing infectious diseases, however their arguments are not based on reliable medical data. Contrary to false theories, the threat of infectious diseases is not lower than in the past. What is more, it has escalated in recent years as a result of the increasing number of parents who avoid vaccinations. Nevertheless, erroneous arguments find a breeding ground among parents or guardians of children covered by vaccination programs undermining trust in vaccines in general. In this situation, it is the responsibility of: physicians who provide preventive care for children, administrative bodies responsible for implementing immunization but also medical schools and other healthcare institutions, on the one hand to raise the level of social awareness about the meaning of vaccination, and on the other to effectively oppose the anti-vaccine propaganda. The way to achieve these goals is to thoroughly understand social needs and constantly improve the professional qualifications of primary care physicians, midwives, community nurses and doctors of different specialties who have daily contact with children and their parents. The key area of focus should also be to place greater emphasis on education about the prevention of infectious diseases among students of all medical school faculties.

One or two doses of live varicella virus-containing vaccines: Efficacy, persistence of immune responses, and safety six years after administration in healthy children during their second year of life.

BACKGROUND: This phase III B follow-up of an initial multicenter study (NCT00226499) will evaluate the ten-year efficacy of two doses of the combined measles-mumps-rubella-varicella vaccine (MMRV) and one dose of the live attenuated varicella vaccine (V) versus a measles-mumps-rubella control group (MMR) for the prevention of clinical varicella disease. Here we present efficacy results for six years post-vaccination. METHODS: In phase A of the study, healthy children aged 12-22 months from ten European countries were randomized (3:3:1) and received either two doses of MMRV, or one dose of combined MMR and one dose of monovalent varicella vaccine (MMR+V), or two doses of the MMR vaccine (control), 42 days apart. Vaccine efficacy against all and against moderate or severe varicella (confirmed by detection of viral DNA or epidemiological link) was assessed from six weeks up to six years post-dose 2 for the MMRV and MMR+V groups, and was calculated with 95% confidence intervals (CI). The severity of varicella was calculated using the modified Vázquez scale (mild ≤ 7; moderately severe = 8-15; severe ≥ 16). Herpes zoster cases were also recorded. RESULTS: 5289 children (MMRV = 2279, mean age = 14.2, standard deviation [SD] = 2.5; MMR+V = 2266, mean age = 14.2, SD = 2.4; MMR = 744, mean age = 14.2, SD = 2.5 months) were included in the efficacy cohort. 815 varicella cases were confirmed. Efficacy of two doses of MMRV against all and against moderate or severe varicella was 95.0% (95% CI: 93.6-96.2) and 99.0% (95% CI: 97.7-99.6), respectively. Efficacy of one dose of varicella vaccine against all and against moderate or severe varicella was 67.0% (95% CI: 61.8-71.4) and 90.3% (95% CI: 86.9-92.8), respectively. There were four confirmed herpes zoster cases (MMR+V = 2, MMR = 2), all were mild and three tested positive for the wild-type virus. CONCLUSIONS: Two doses of the MMRV vaccine and one dose of the varicella vaccine remain efficacious through six years post-vaccination.

A randomized study of fever prophylaxis and the immunogenicity of routine pediatric vaccinations.

OBJECTIVE: Prophylactic antipyretic use during pediatric vaccination is common. This study assessed whether paracetamol or ibuprofen prophylaxis interfere with immune responses to the 13-valent pneumococcal conjugate vaccine (PCV13) given concomitantly with the combined DTaP/HBV/IPV/Hib vaccine. METHODS: Subjects received prophylactic paracetamol or ibuprofen at 0, 6-8, and 12-16 h after vaccination, or 6-8 and 12-16 h after vaccination at 2, 3, 4, and 12months of age. At 5 and 13months, immune responses were evaluated versus responses in controls who received no prophylaxis. RESULTS: After the infant series, paracetamol recipients had lower levels of circulating serotype-specific pneumococcal anticapsular immunoglobulin G than controls, reaching significance (P<0.0125) for 5 serotypes (serotypes 3, 4, 5, 6B, and 23F) when paracetamol was started at vaccination. Opsonophagocytic activity assay (OPA) results were similar between groups. Ibuprofen did not affect pneumococcal responses, but significantly (P<0.0125) reduced antibody responses to pertussis filamentous hemagglutinin and tetanus antigens after the infant series when started at vaccination. No differences were observed for any group after the toddler dose. CONCLUSIONS: Prophylactic antipyretics affect immune responses to vaccines; these effects vary depending on the vaccine, antipyretic agent, and time of administration. In infants, paracetamol may interfere with immune responses to pneumococcal antigens, and ibuprofen may reduce responses to pertussis and tetanus antigens. The use of antipyretics for fever prophylaxis during infant vaccination merits careful consideration. ClinicalTrials.gov identifier: NCT01392378https://clinicaltrials.gov/ct2/show/NCT01392378?term=NCT01392378&rank=1.

Circulating Antibody 1 and 2 Years After Vaccination With the 13-Valent Pneumococcal Conjugate Vaccine in Preterm Compared With Term Infants.

BACKGROUND: Premature infants have lower short-term immune responses to vaccination than term infants, but patterns of antibody persistence in preterm infants over longer periods are not well established. This study assessed the persistence of antibody response to the 13-valent pneumococcal conjugate vaccine (PCV13) in formerly preterm versus term infants. METHODS: In total, 100 preterm and 100 term infants received PCV13 with routine vaccines at ages 2, 3, 4 and 12 months. Serotype-specific anticapsular immunoglobulin G (IgG)-binding antibodies and opsonophagocytic activity were determined 1 and 2 years after the last PCV13 dose. RESULTS: At 1 and 2 years after the last vaccination (toddler dose), IgG geometric mean concentrations (GMCs) for all serotypes had declined from levels measured 1 month after the toddler dose but remained above pretoddler dose levels. IgG GMCs were significantly lower in preterm than term subjects for a majority of serotypes at both follow-up time points. IgG GMCs increased in both groups for some serotypes from the 1-year to 2-year follow-up, whereas others declined. Opsonophagocytic activity results supported the IgG results. CONCLUSIONS: The routine (3 + 1) vaccination schedule is likely to offer long-term protection against invasive pneumococcal disease in preterm infants and should be initiated regardless of gestational age or weight at birth, without delay of the toddler dose.

13-valent pneumococcal conjugate vaccine (PCV13) in preterm versus term infants.

OBJECTIVES: This study evaluated the immune response and safety profile of 13-valent pneumococcal conjugate vaccine (PCV13) in preterm infants compared with term infants. METHODS: This Phase IV, open-label, 2-arm, multicenter, parallel-group study enrolled 200 healthy infants (preterm, n = 100; term, n = 100) aged 42 to 98 days. All subjects received PCV13 at ages 2, 3, 4 (infant series), and 12 (toddler dose [TD]) months, together with routine vaccines (diphtheria-tetanus-acellular pertussis, hepatitis B, inactivated poliovirus, and Haemophilus influenzae type b vaccine and meningococcal group C conjugate vaccine). RESULTS: Most subjects achieved an anticapsular immunoglobulin G (IgG) antibody concentration ≥ 0.35 µg/mL for all serotypes: >85% after the infant series (except preterm infants for serotypes 5, 6A, and 6B) and >97% after TD (except for serotype 3). Preterm infants had overall lower IgG geometric mean concentrations compared with term infants; however, geometric mean fold increases after TD were similar for all serotypes. Opsonophagocytic activity results were consistent with IgG results and titers increased after TD in both groups for all serotypes, including serotype 3. PCV13 was generally well tolerated, with similar safety profiles in all preterm subgroups. CONCLUSIONS: Immune responses were lower in preterm infants than in term infants. However, the majority of subjects in both groups achieved both pneumococcal serotype-specific IgG antibody levels after the infant series that exceeded the World Health Organization-established threshold of protection and functional antibody responses. Responses were uniformly higher after TD, reinforcing the importance of a timely booster dose. PCV13 was well tolerated regardless of gestational age.

Safety and immunogenicity of a 13-valent pneumococcal conjugate vaccine manufactured with and without polysorbate 80 given to healthy infants at 2, 3, 4 and 12 months of age.

BACKGROUND: Polysorbate 80 (P80), a nonionic detergent used to solubilize proteins, is used in both oral and injectable medications including vaccines. Development studies with 13-valent pneumococcal conjugate vaccine (PCV13) showed that adding P80 resulted in a more robust manufacturing process. Before adding P80 to the formulation of PCV13, we investigated the immunogenicity and safety of PCV13 with and without P80. METHODS: Phase 3, parallel-group, randomized, active-controlled, double-blind multicenter trial was conducted at 15 sites in Poland. Healthy infants were randomized (1:1) to receive PCV13+P80 or PCV13 without P80 given at ages 2, 3, 4 and 12 months concomitantly with DTaP-IPV-Hib at 2, 3 and 4 months; hepatitis B at 2 months and measles, mumps, and rubella at 12 months. Serotype-specific antipneumococcal immune responses were evaluated using antipolysaccharide capsular immunoglobulin (Ig)G responses and opsonophagocytic activity (OPA) assay. Safety data were also collected. RESULTS: The 2 treatment groups were demographically similar. Following the infant immunization series, anticapsular IgG antibody geometric mean concentrations and OPA geometric mean titers for each serotype were within 2-fold between the 2 groups. Formal noninferiority criteria for comparison of proportion of responders (subjects with IgG titers ≥0.35 µg/mL) were met for 11 of the 13 serotypes. Overall population responses were highly similar. Anticapsular IgG responses were also within 2-fold following the toddler dose. Safety profiles were similar between the 2 groups. CONCLUSIONS: Addition of P80 to PCV13 did not adversely affect PCV13 immunogenicity or safety when compared with vaccine formulated without P80.

Vaccination of preterm infants by polyvalent vaccines: immunogenicity and safety- review of literature.

The immunization of infants against infectious diseases still raises many controversies, not only with parents, but also among physicians. This refers particularly to preterm infants. Due to the increasing popularity of polyvalent vaccines, a number of studies has recently been conducted to verify their immunogenicity and safety in preterm infants. The aim of the present paper was to review the current literature dealing with the problem in question. The following recommendations regarding the use of polyvalent vaccines in preterm infants and neonates with low birth weight can be formulated on the basis of current evidence (1). Due to sufficient immunogenicity, polyvalent vaccines can be administered to preterm infants in accordance with their calendar age (2). Booster vaccination of preterm infants after completing 12 months of age is vital for achieving complete and persistent immunity against all vaccine antigens (3). In order to reduce the risk of adverse events after the administration of a polyvalent vaccine, it is essential to carefully consider the cardiorespiratory status of preterm infants during preimmunization examination, as well as their history of any cardiorespiratory dysfunctions. In such cases administering the first dose of the vaccine in a hospital setting is strongly advised.