Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age.

BACKGROUND: Safe, effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in children younger than 12 years of age. METHODS: A phase 1, dose-finding study and an ongoing phase 2-3 randomized trial are being conducted to investigate the safety, immunogenicity, and efficacy of two doses of the BNT162b2 vaccine administered 21 days apart in children 6 months to 11 years of age. We present results for 5-to-11-year-old children. In the phase 2-3 trial, participants were randomly assigned in a 2:1 ratio to receive two doses of either the BNT162b2 vaccine at the dose level identified during the open-label phase 1 study or placebo. Immune responses 1 month after the second dose of BNT162b2 were immunologically bridged to those in 16-to-25-year-olds from the pivotal trial of two 30-µg doses of BNT162b2. Vaccine efficacy against Covid-19 at 7 days or more after the second dose was assessed. RESULTS: During the phase 1 study, a total of 48 children 5 to 11 years of age received 10 µg, 20 µg, or 30 µg of the BNT162b2 vaccine (16 children at each dose level). On the basis of reactogenicity and immunogenicity, a dose level of 10 µg was selected for further study. In the phase 2-3 trial, a total of 2268 children were randomly assigned to receive the BNT162b2 vaccine (1517 children) or placebo (751 children). At data cutoff, the median follow-up was 2.3 months. In the 5-to-11-year-olds, as in other age groups, the BNT162b2 vaccine had a favorable safety profile. No vaccine-related serious adverse events were noted. One month after the second dose, the geometric mean ratio of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing titers in 5-to-11-year-olds to those in 16-to-25-year-olds was 1.04 (95% confidence interval [CI], 0.93 to 1.18), a ratio meeting the prespecified immunogenicity success criterion (lower bound of two-sided 95% CI, >0.67; geometric mean ratio point estimate, ≥0.8). Covid-19 with onset 7 days or more after the second dose was reported in three recipients of the BNT162b2 vaccine and in 16 placebo recipients (vaccine efficacy, 90.7%; 95% CI, 67.7 to 98.3). CONCLUSIONS: A Covid-19 vaccination regimen consisting of two 10-µg doses of BNT162b2 administered 21 days apart was found to be safe, immunogenic, and efficacious in children 5 to 11 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

Safety and Immunogenicity of a ChAd155-Vectored Respiratory Syncytial Virus Vaccine in Infants 6-7 Months of age: A Phase 1/2 Randomized Trial.

BACKGROUND: Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract infections in infants. This phase 1/2, observer-blind, randomized, controlled study assessed the safety and immunogenicity of an investigational chimpanzee-derived adenoviral vector RSV vaccine (ChAd155-RSV, expressing RSV F, N, and M2-1) in infants. METHODS: Healthy 6- to 7-month-olds were 1:1:1-randomized to receive 1 low ChAd155-RSV dose (1.5 × 1010 viral particles) followed by placebo (RSV_1D); 2 high ChAd155-RSV doses (5 × 1010 viral particles) (RSV_2D); or active comparator vaccines/placebo (comparator) on days 1 and 31. Follow-up lasted approximately 2 years. RESULTS: Two hundred one infants were vaccinated (RSV_1D: 65; RSV_2D: 71; comparator: 65); 159 were RSV-seronaive at baseline. Most solicited and unsolicited adverse events after ChAd155-RSV occurred at similar or lower rates than after active comparators. In infants who developed RSV infection, there was no evidence of vaccine-associated enhanced respiratory disease (VAERD). RSV-A neutralizing titers and RSV F-binding antibody concentrations were higher post-ChAd155-RSV than postcomparator at days 31, 61, and end of RSV season 1 (mean follow-up, 7 months). High-dose ChAd155-RSV induced stronger responses than low-dose, with further increases post-dose 2. CONCLUSIONS: ChAd155-RSV administered to 6- to 7-month-olds had a reactogenicity/safety profile like other childhood vaccines, showed no evidence of VAERD, and induced a humoral immune response. Clinical Trials Registration. NCT03636906.

Three-Dimensional Echocardiography and Global Longitudinal Strain in Follow-Up After Multisystem Inflammatory Syndrome in Children: Six-Month, Single-Center, Prospective Study.

OBJECTIVE: To assess the potential long-term cardiac effects after multisystem inflammatory syndrome in children (MIS-C) with cardiovascular involvement in the acute phase. STUDY DESIGN: Our prospective study involved children consecutively diagnosed with MIS-C between October 2020 and February 2022 and followed 6 weeks and 6 months after the disease. In patients with severe cardiac involvement during the acute phase, an additional check-up after 3 months was scheduled. In all patients at all check-ups, 3-dimensional echocardiography and global longitudinal strain (GLS) were used to assess ventricular function. RESULTS: The study enrolled 172 children aged 1-17 years (median, 8 years). The means of ejection fraction (EF) and GLS for both ventricles were within normal limits after 6 weeks with no relationship with initial severity: left ventricular EF (LVEF) 60% (59%-63%), LV GLS -21.08% (-18.63% to -23.2%), right ventricular (RV) EF 64% (62%-67%), and RV GLS -22.8% (-20.5% to -24.5%). Further, statistically significant improvement of LV function was observed after 6 months-LVEF 63% (62%-65%) and LV GLS -22.55% (-21.05% to -24.25%; P < .05); however, RV function remained unchanged. The group with severe cardiac involvement showed LV function recovery pattern with no significant improvement between 6 weeks and 3 months after MIS-C, while still improving between 3 and 6 months after discharge. CONCLUSIONS: LV and RV function is within normal limits 6 weeks after MIS-C regardless of severity of cardiovascular involvement; LV function improves further between 6 weeks and 6 months after the disease. The long-term prognosis is optimistic with full recovery of cardiac function.

The anti-infective effect of ß-glucans in children.

Background: ß-glucans are bioactive ß-D-glucose polysaccharides of natural origin, presenting antimicrobial and immunomodulation properties, with a low risk of toxicity. Objectives: This scoping review aims to present the current knowledge on the anti-infective properties of ß-glucans in the pediatric population. Methods: We used the PRISMA Extension for Scoping Reviews Checklist to prepare this review. Studies were identified by electronic searches of Pubmed, Embase, and Cochrane databases up to May 2021. Results: The primary search allowed us to find 6232 studies, twelve of which were finally included in the analysis. Eight studies were designed as randomized, placebo-controlled trials, while in four studies the intervention outcome was compared with the pre-intervention period in the same group. The type of preparation and doses varied between studies: in five trials pleuran was administered (in dose 10 mg/5 kg of body weight/day), and in one study baker's yeast ß-glucan was used (in two doses: 35 mg/day and 75 mg/day). In six other studies, the analyzed preparation comprised ß-glucan and other substances. The shortest study lasted seven days, while the most prolonged intervention lasted six months, followed by six months of follow-up. Ten out of twelve trials demonstrated the effectiveness of ß-glucans in reducing respiratory tract infection incidence or alleviation of upper respiratory tract infection symptoms. Ten out of twelve studies have reported a good tolerance and safety profile. Conclusions: Good tolerance of ß-glucans shows a favorable benefit-risk ratio of this type of intervention. Nevertheless, further monitoring of their efficacy and safety in high-quality research is necessary.

A 10-Year-old Girl With Late Acute Lymphoblastic Leukemia Recurrence Diagnosed With COVID-19 and Treated With Remdesivir.

Patients with hemato-oncologic diseases are particularly vulnerable to severe infections. Adult patients with blood cancers infected with SARS-CoV-2 had poorer treatment outcomes and higher mortality than patients with COVID-19 without burden. However, in pediatric patients with hemato-oncologic diseases the course of COVID-19 is milder than in adults in the same group of patients. In this report, we describe the case of our patient with acute lymphoblastic leukemia infected with SARS-CoV-2 and treated with remdesivir. We also review the existing literature of pediatric patients who have been diagnosed with both hemato-oncologic diseases and COVID-19.

Effects of Non-Opioid Analgesics on the Cell Membrane of Skin and Gastrointestinal Cancers.

Skin and gastrointestinal cancer cells are the target of research by many scientists due to the increasing morbidity and mortality rates around the world. New indications for drugs used in various conditions are being discovered. Non-opioid analgesics are worth noting as very popular, widely available, relatively cheap medications. They also have the ability to modulate the membrane components of tumor cells. The aim of this review is to analyze the impact of diclofenac, ibuprofen, naproxen, acetylsalicylic acid and paracetamol on skin and gastrointestinal cancers cell membrane. These drugs may affect the membrane through topical application, at the in vitro and in vivo level after oral or parenteral administration. They can lead to up- or downregulated expression of receptors, transporters and other molecules associated with plasma membrane. Medications may also alter the lipid bilayer composition of membrane, resulting in changes in its integrity and fluidity. Described modulations can cause the visualization of cancer cells, enhanced response of the immune system and the initiation of cell death. The outcome of this is inhibition of progression or reduction of tumor mass and supports chemotherapy. In conclusion, non-opioid analgesics may be used in the future as adjunctive therapy for the treatment of these cancers.

SARS-CoV-2 Cluster in Nursery, Poland.

We report a cluster of surprisingly high spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associated with a single nursery in Poland. Our findings contrast with the presumed negligible role of children in driving the SARS-CoV-2 pandemic. Children 1-2 years of age might be effective SARS-CoV-2 spreaders.

Recurrent assessment of lymphocyte subsets in 32 patients with multisystem inflammatory syndrome in children (MIS-C).

BACKGROUND: Lymphopenia is a hallmark of multisystem inflammatory syndrome in children (MIS-C). We aimed to characterize lymphocyte subsets' shifts and their correlations with other severity markers of MIS-C. METHODS: In this prospective cross-sectional study, we performed peripheral lymphocyte phenotyping in 32 patients with MIS-C. We analyzed lymphocyte subsets at three time points of the disease: the acute (A), convalescent (B), and recovery (C) phases. Based on age-normalized lymphocyte counts, we distinguished two groups of patients: "the mild" (higher lymphocyte counts) and "the severe" (lower lymphocyte counts). In addition, we examined differences between these groups regarding other severity markers. RESULTS: In phase A, 84% of children had lymphopenia. Decreased absolute counts of CD3, CD4, and CD8 cells were observed in, respectively, 88%, 72%, and 84% of patients. The natural killer cells were decreased in 63% and CD19 in 59% of children. "The severe" group had significantly higher procalcitonin and troponin I levels and lower platelets and albumin. Moreover, "the severe" group had hypotension more frequently (73% vs. 20%, p = .008). In phase B, all lymphocyte counts increased, and 32% of children had lymphocytosis. The increase of CD3, CD4, and CD8 counts correlated with some laboratory severity markers (hemoglobin, procalcitonin, D-dimer, lactate dehydrogenase, N-terminal prohormone of brain natriuretic peptide, albumin), but not with steroid use. In phase C, most children had normal lymphocyte counts. CONCLUSIONS: Substantial shifts in lymphocyte counts during MIS-C apply most to T lymphocytes and correlate with the disease severity markers, particularly hypotension prevalence. A proportion of children with MIS-C develops transient lymphocytosis during convalescence.

Children were less frequently infected with SARS-CoV-2 than adults during 2020 COVID-19 pandemic in Warsaw, Poland.

Clinical data suggest that during the current COVID-19 pandemic, children are less prone than adults to SARS-CoV-2 infection. Our purpose was to determine the frequency of SARS-CoV-2 in children vs. adults during the 2020 pandemic in Warsaw, Poland, and to investigate whether RSV and/or influenza A/B infections were associated with SARS-CoV-2 infections. We present results of RT-PCR tests for SARS-CoV-2 performed in Warsaw, Poland. Some of the pediatric subjects were also PCR-tested for RSV, and A and B influenza. We compared the test results from the four groups of symptomatic and asymptomatic subjects: 459 symptomatic pediatric patients (children 0-18 years old), 1774 symptomatic adults, 445 asymptomatic children, and 239 asymptomatic adults. 3.26% (15/459) of symptomatic pediatric patients were positive for SARS-CoV-2 in contrast to 5.58% (99/1774) of symptomatic adults (p = 0.0448). There were no SARS-CoV-2 positive cases in the group of asymptomatic children (0/445) and two positive cases in the group of asymptomatic adults (2/239), i.e., 0.83%. In the group of symptomatic pediatric patients, 17.14% (6/35) (p = 0.0002) were positive for RSV, 8.16% (4/49) were positive for influenza A, and 2.04% (1/49), thus 10.20% (5/49) (p = 0.0176) for influenza A/B. Children were less prone to SARS-CoV-2 infection than the adults during the COVID-19 pandemic in Warsaw. Higher percentage of symptomatic children was infected with RSV or influenza A/B than with SARS-CoV-2. This suggests a necessity for the testing for all these viruses for an early identification and isolation of SARS-CoV-2-positive patients for an ensuing 2020 autumn return of COVID-19.

Safety and Impact on Training of the Influenza Vaccines in Elite Athletes Participating in the Rio 2016 Olympics.

OBJECTIVE: The aim of the study was to evaluate the safety and tolerance of influenza vaccines for the northern and southern hemispheres in Polish elite athletes participating in the Rio 2016 Olympics. DESIGN: Prospective, observational, cohort study. SETTING: Institutional level. PARTICIPANTS: Ninety-seven athletes vaccinated only with the northern hemisphere vaccine; 98 athletes received the southern hemisphere vaccine alone, whereas 39 athletes were vaccinated with both vaccines. INTERVENTIONS: The athletes were vaccinated with a trivalent, inactivated influenza vaccine recommended for the northern hemisphere 2015/2016 and then with the vaccine recommended for the southern hemisphere 2016. Athletes kept a diary of adverse events and effects (if any) on training for 6 days after vaccination. MAIN OUTCOME MEASURES: The percentage of general and local adverse events, number of lost or modified training sessions. RESULTS: Significantly more local adverse events (pain and redness) were found in the group immunized with the vaccine for the northern hemisphere. There were no differences in the frequency of general adverse events and influence on training between groups. Of total 273 athletes who had 1911 training days during 6 days after vaccination, 6 athletes (2.2%) lost 13 training days (0.7%) and 16 athletes (5.9%) had to modify 34 (1.7%) training days within first 2 days after vaccination. CONCLUSIONS: Athletes tolerated influenza immunization well. If they are going to travel to the other hemisphere during the influenza season, the use of the second influenza vaccine should be advised. Athletes should anticipate modification of trainings for 2 days after vaccination.

Development of child immunity in the context of COVID-19 pandemic.

Children, because of having an immature immune system, are usually more prone than the adults to the microbial infections and have more severe symptoms, which is especially true for the newborns, and very young children. However, the review of clinical data from the current COVID-19 pandemic indicates otherwise. We discuss here what are the main features and components of children's immune system, the role of maternal transmission of immunity, and what are the possible explanations for the seemingly lower infection rate and severity of COVI-19 in children.

Decreasing Vaccination Coverage Against Hepatitis B and Tuberculosis in Newborns.

The number of parents who refuse to vaccinate their children or present the so-called hesitant behavior, i.e., delay the moment of vaccination beyond the mandatory time, has increased in many developed countries. The purpose of this retrospective study was to evaluate the completeness and timeliness of vaccinations against hepatitis B (HBV) and tuberculosis (TB) in neonates in a single maternity hospital in Warsaw, Poland. We reviewed medical files of 14,785 children born in the hospital in 2015-2017 and calculated the proportion of newborns not vaccinated on time according to the Polish Immunization schedule that includes vaccination against HBV and TB in the first day of life. Newborns remained unvaccinated because of parental refusal (refusers) or decision for a delay (hesitants), or medical contraindications. The percentage of unvaccinated newborns in the 3 years was as follows: 7.3% in 2015, 6.7% in 2016, and 10.1% in 2017. Parental decisions rather than medical contraindications caused nonvaccination (4.4% vs. 2.9% in 2015, 4.7% vs. 2.0% in 2016, and 7.5% vs. 2.6% in 2017). The majority of refusals concerned both vaccinations (67.3% in 2015, 74.8% in 2016, and 68% in 2017). Among parents who refused only one vaccination, TB vaccination was refused more often than HBV (9.2% vs. 7.1% in 2015, 8.3% vs. 5.7% in 2016, and 5.9% vs. 2.7% in 2017). Similar trends were observed among the hesitants. In conclusion, it seems essential to implement effective educational and informative activities targeted to parents to reinforce positive attitudes toward vaccinations.

The clinical course of gastroenteritis due to nosocomial and community acquired norovirus infections in immunocompromised and immunocompetent children - single center experience.

BACKGROUND: After the introduction of rotavirus vaccines into immunization schedules, noroviruses account for the majority of acute gastrointestinal infections. The aim of the study was to assess the clinical presentation in immunocompromised and immunocompetent children with hospital- and community-acquired norovirus gastroenteritis. MATERIAL AND METHODS: We retrospectively reviewed clinical records of children with noroviral gastroenteritis, hospitalized in the Pediatric Hospital, Medical University of Warsaw, between 2015 and 2018. Acute gastrointestinal tract symptoms and confirmed etiology of noroviral infection were inclusion criteria. The analysis was performed in the subgroups of immunocompetent and immunocompromised patients, during community-acquired and nosocomial infections. RESULTS: A total of 57 children with median age 1.5 year (IQR: 0.7-4.0) were recruited. The majority of patients were immunocompetent (87.7%), and nosocomial infections were predominant (56.1%). Gastrointestinal symptoms included nausea, vomiting and diarrhoea (in approximately 85%), while systemic manifestations such as fever and malaise where observed in only ». Routine laboratory tests were normal in most of the patients. An analysis in the subgroups revealed statistically significant differences in blood pH and serum electrolyte levels - acidosis and electrolyte disturbances were statistically significantly more common in immunocompromised vs immunocompetent patients (p<0.05). CONCLUSIONS: More frequently the clinical presentation includes gastrointestinal symptoms with no differences between immunocompromised and immunocompetent hosts. The median laboratory values were normal in generally healthy children; disturbances were observed only in children with immunodeficiencies. Therefore, prophylactic measures are of particular importance in the latter group, which is especially sensitive to severe and nosocomial infections.

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.

Genetic Predisposition for Osteoporosis and Fractures in Postmenopausal Women.

Osteoporosis is a disease with complex etiology where the genetic factors may account for as much as 50-85% of the risk of its development in postmenopausal women. The polymorphism of estrogen receptor genes (ESR1, ESR2) seems essential among the genetic factors. The goal of this study was to analyze polymorphisms of selected genes in a population of postmenopausal women treated for osteoporosis and to evaluate the influence of genetic and nongenetic factors on the estimated 10-year risk of fracture. The study group consisted of 214 women hospitalized for treatment of postmenopausal osteoporosis. We investigated the presence of ESR1, ESR2, LRP5, and WNT16 genetic polymorphisms and the risk of fracture in each woman. The main finding was that of significant differences in the polymorphisms of the WNT16 rs2908004 genetic variant, notably, the less frequent presence of TC allele in women with a greater risk of osteoporotic fractures. We conclude that the polymorphism of the WNT16 gene seems highly relevant in the pathogenesis of osteoporosis, which makes it a promising object for further research on the genetic background of fracture risk.

Autologous Platelet-Rich Plasma Reduces Healing Time of Chronic Venous Leg Ulcers: A Prospective Observational Study.

The study investigated whether the application of dressings with autologous platelet-rich plasma (PRP) would reduce the healing time in patients with chronic venous leg ulcers. This is a prospective observational study that included 100 patients diagnosed with lower extremity venous insufficiency complicated by ulceration of a leg or foot, who had been after angioplasty of stenotic artery. Patients were divided into two groups of 50 each: treated with PRP (study group) and treated with conventional hydrocolloid dressings (control group). We followed the wound changes at Day 10, Day 20, and Day 30 of treatment and compared them with the baseline appearance at Day 0. We evaluated the appearance, area, and depths of wounds with ultrasound. The granulation process was examined histologically to document skin formation and wound tissue neovascularization. The findings were that treatment with PRP dressings resulted in a significant progressive reduction in ulcer size, irrespective of the ulcer's initial size, compared to treatment with conventional dressings. Further, the best effect of PRP was noticed in the category of largest wounds. After a month of treatment with PRP dressings, more than 50% of all ulcers were completely healed. The young epidermis appeared together with the granulation tissue, and the formation of dermis took shape after 20 days of treatment. We conclude that the use of PRP dressings is a safe, nonsurgical adjunctive procedure for treating chronic venous leg ulcers. The potential benefit of PRP dressings over conventional ulcer treatment requires further in-depth exploration.

Healthcare Professionals' Knowledge of Influenza and Influenza Vaccination: Results of a National Survey in Poland.

In Poland, the seasonal influenza vaccination rate is just barely 3% which may be related to the unsatisfactory knowledge of influenza among healthcare professionals, poor recognition of the benefits of influenza immunization and the fear of side effects. To address these issues, we surveyed healthcare professionals through an online questionnaire consisting of 18 closed-ended items. The questionnaire was completed by 495 healthcare professionals, mostly physicians (83%). The results revealed gaps in the knowledge concerning influenza diagnosis, complications, risk groups, and prognostic factors. On average, respondents only answered 4.8 of the 18 questions correctly (27%). Only 10% of respondents passed the threshold of 50% correct answers. The knowledge of contraindications to vaccination far outweighed the knowledge of indications for vaccination. Poor knowledge with a focus on the adverse effects of immunization may be a significant factor responsible for the low vaccination rate in Poland. To increase vaccination rate, healthcare professionals need to be educated about influenza-related risks and benefits of vaccination.

Evaluation of the Implementation of Hospital Antibiotic Policy in Oncosurgery Ward: A Six-Year Experience.

The hospital antibiotic policy should be implemented to rationalize the antibiotic use and to decrease the risk of spread of resistant bacteria. The aim of this study was to describe the antibiotic consumption patterns in a single oncosurgery ward before and after the implementation of hospital antibiotic policy. We conducted a retrospective analysis of the antibiotic use at the oncosurgery ward in Warsaw, Poland, in the years 2011-2016. Calculations were based on daily defined doses (DDD), DDD/100 hospitalizations, and DDD/100 person-days. Drug utilization rates (DU 90% and DU 100%) were also analyzed. After the implementation of hospital antibiotic policy, a total antibiotic consumption increased (365.35 DDD in 2011 vs. 1359.22 DDD in 2016). A significant change was observed in the antibiotic consumption patterns: the use of amoxicillin clavulanate and carbapenems or glycopeptides decreased significantly (p < 0.05), while the use of ciprofloxacin and aminoglycosides increased (p < 0.05). The DU100% rate varied from 6 in 2011 to 12 in 2016; while DU 90% rate varied from 2 in 2011 to 3-5 in 2013-2016. Although the implementation of hospital antibiotic policy did not result in a decrease in the antibiotic consumption, it seems to provide a favorable change into the antibiotic consumption pattern.

Knowledge Regarding Influenza and Influenza Vaccination in General Population: Results of a National Survey in Poland.

For the past 10 years, influenza vaccination coverage rate in Poland remains at a low 3% threshold. This low rate may be related to the unsatisfactory knowledge of vaccination, influenza, and misperception of health risks in the general population. To examine these issues, we used an online questionnaire consisting of 12 closed questions. The basic knowledge on influenza and vaccination was examined. The questionnaire was completed by 1669 persons, mostly young women. Generally, 73% of respondents passed the threshold of 70% correct answers, but important gaps in their knowledge were identified concerning the persons at risk of developing the infection (7.9% of correct answers) and the timing of vaccination (8.4% of correct answers). Although most respondents did identify the etiologic agent correctly (91.1% knew influenza is caused by a virus), only 12.3% knew that the vaccines registered in Poland contain fragments of viruses or its antigens, while 63.1% thought the vaccines contain live bacteria. In conclusion, the knowledge on influenza vaccination is deficient in the general population. Education on immunization should be prioritized to increase vaccination coverage rate in Poland.

Antibody Response to Trivalent Influenza Vaccine in the Northern and the Southern Hemisphere in Elite Athletes.

Being frequent travelers, the elite athletes are advised to undergo an influenza vaccination. The aim of the study was to describe the antibody response to repeated trivalent, inactivated, split influenza vaccine, of different antigenic content, recommended for the Northern and the Southern Hemisphere, administered to sportsmen before the Olympic Games in Brasil in 2016. Fourteen athletes were included in the study. For both A/California/7/209/pdm09 A/H1N1/ antigen and A/Switzerland/971593/2013/A/H3N2/ antigen, higher seroconversion rates were obtained after the first than the second vaccination (10.2 vs. 1.5 and 10.6 vs. 3.0, respectively; p < 0.05 both). Conversion rates for B/Phuket/3073/2013, B/Brisbane/60/2008, and A/HongKong/4801/2014/A/H3N2/ antigens were lower. Nonetheless, the protection rate was greater than 70% for all antigens contained in both vaccines. The proportion of individuals demonstrating a high level of both protection rate and response rate was greater after the first than the second vaccination. We conclude that the immunological response after influenza vaccination is good in elite athletes and remains so after a second influenza vaccination required due to a different vaccine composition recommended for different hemispheres.