Diphtheria / Tetanus / Pertussis (acellular component) / Hepatitis B (surface antigen) / Poliomyelitis (inactivated) / Haemophilus type b conjugate vaccine (adsorbed) powder and suspension for suspension for injection 0.5ml pre-filled syringes

Background: Many human activities release harmful substances, contaminating the air, water, and soil. Since exposure to environmental pollutants is currently unavoidable, it is important to verify how these compounds may influence individual immune responses to vaccines. Methods: This review was conducted in accordance with the PRISMA statement. The protocol was registered on the PROSPERO platform with the following ID: CRD42024582592. We evaluated all observational, semi-experimental, and experimental studies written in both Italian and English that reported possible effects of exposure to environmental pollutants on the production of vaccine-induced antibodies. Results: Forty-two studies were included. The effects of pollutants were examined mainly in terms of antibody production in relation to mumps, measles and rubella, diphtheria and tetanus, hepatitis A and B, Haemophilus influenzae type B, influenza, tuberculosis, pertussis, Japanese encephalitis, poliomyelitis, and COVID-19 vaccines. Perfluorinated compounds were the most studied pollutants. Conclusions: Correlations between exposure to pollutants and reductions in antibody production were found in quite all the selected studies, suggesting that pollution control policies could contribute to increase the efficacy of vaccination campaigns. However, the heterogeneity of the examined studies did not allow us to perform a meta-analysis, and the literature on each type of vaccine or pollutant is still too limited to generate robust evidence. In order to confirm the findings of the present systematic review, and in the perspective of establishing possible exposure limit values for each type of pollutant, further research in this field is required.

Abstract licence: CC BY

Background: Co-administration of vaccines can impact the immune response and safety. We aim to systematically review the current scientific literature and find evidence regarding the immunogenicity and safety of pneumococcal vaccines co-administered with common vaccines that are recommended for travelers, including hepatitis A, hepatitis B, yellow fever, tetanus, diphtheria, and acellular pertussis (Tdap), Japanese encephalitis, rabies, typhoid, or meningococcal (MCV) vaccine in adults (18 years or older). Methods: We followed the PRISMA 2020 guidelines and used the PICOS process to select the keywords. We searched PubMed, Web of Science, Scopus, EMBASE, and Google from 1 January 2000 to 30 June 2024. We included randomized controlled trials, non-randomized controlled trials, observational studies, case series, and case reports in adults, all published in English. Results: Out of 598 articles screened, 6 studies were included in our study. Three studies involved immunocompetent individuals, and three involved immunocompromised individuals. Co-administration of pneumococcal vaccine with Tdap or Hepatitis A in immunocompetent individuals was safe and immunogenic. Similar findings were reported for immunocompromised individuals when pneumococcal vaccines were co-administered with Tdap, hepatitis A, and hepatitis B. However, no reports investigated the co-administration of yellow fever, rabies, Japanese encephalitis, and typhoid. Two non-randomized studies in immunocompromised individuals had a high risk of bias. Conclusions: The studies collectively indicate that the co-administration of pneumococcal vaccines with Hepatitis A and Tdap vaccines in adult immunocompetent and immunocompromised individuals is safe and immunogenic. However, a knowledge gap remains, and further high-quality studies are needed, particularly due to the limited number of studies and the potential risk of bias.

Abstract licence: CC BY

Background: Acute lymphoblastic leukemia is the most prevalent childhood cancer and the leading cause of cancer mortality before the age of 20. Although therapeutic advances have significantly improved survival, children and adolescents treated for acute lymphoblastic leukemia remain vulnerable to infections, largely preventable by vaccination, due to humoral and cellular immune dysfunction induced by disease and treatment. Materials and Methods: This systematic review, based on electronic databases, aims to evaluate antibody levels associated with potential protective immunity against vaccine antigens for diphtheria, pertussis, tetanus, poliomyelitis, Haemophilus influenzae type b, measles, mumps, rubella, influenza, varicella-zoster virus, yellow fever, pneumococcal, and meningococcal diseases in children and adolescents treated for acute lymphoblastic leukemia after completion of chemotherapy. Results: A total of twenty-four studies published between 1981 and 2023 were included, comprising 1110 children and adolescents. Protective antibody levels ranged from 11% to 97% for diphtheria, 0% to 90% for pertussis, 20% to 100% for tetanus, and 11% to 95% for poliomyelitis. Haemophilus influenzae type b, protection ranged from 16.7% to 100%. Viral vaccines also showed heterogeneous responses, with protection rates of 25–79% for mumps, 16–86% for measles, 35–98% for rubella, and 23–75% for varicella-zoster virus. Antibody responses to pneumococcal and meningococcal vaccines were consistently low, with protection rates of 5–38% for pneumococcal studies and 12% in a single meningococcal study. Conclusions: This review found a consistent and clinically relevant loss of vaccine-induced immunity in children and adolescents treated for acute lymphoblastic leukemia. The recommendation of vaccine booster doses for this vulnerable population, irrespective of serological status, may represent a more practical approach to ensuring adequate post-chemotherapy treatment protection.

Abstract licence: CC BY

Vaccination programs have had a pivotal part in the successful reduction of global morbidity and mortality of infectious diseases. Despite their undeniable success, vaccination rates among children with congenital heart disease (CHD) remain suboptimal. This article aims to address the challenges surrounding immunization in CHD patients and provide guidance for immunization practices within this population. Most experts advocate for adherence to standard immunization practices in CHD patients who are immunocompetent and in good health. Supplemental vaccinations against rotavirus, varicella, meningococcus, hepatitis A and influenza are recommended. RSV prophylaxis with palivizumab is advisable in patients with hemodynamically significant CHD during winter season. However, special considerations are warranted in specific situations, such as around cardiac surgery or in patients who are immunocompromised. Furthermore, adjustments to the vaccination schedule might be necessary for patients who require antithrombotic prophylaxis or blood transfusions. Lastly, special attention should be given to individuals at a high risk of decompensation after immunization, who might require close parental or medical monitoring for up to 72 hours post-vaccination.

Abstract licence: CC BY-ND

Hexyon® is a fully-liquid, ready-to-use, hexavalent vaccine approved in the EU since 2013 for primary and booster vaccination in infants and toddlers from age 6 weeks against diphtheria, tetanus, pertussis, hepatitis B (HB), poliomyelitis, and invasive diseases caused by Haemophilus influenzae type b (Hib). While the source of HB antigen in Hexyon® is different from other vaccines, the rest of its valences have been extensively used in other approved vaccines. Hexyon® is highly immunogenic for all its component toxoids/antigens when used as primary and booster vaccine in infants and toddlers, irrespective of vaccination schedule. It provides durable protection against hepatitis B. Hexyon® can be used for a mixed primary series of hexavalent-pentavalent-hexavalent vaccines or as a booster in infants primed with Infanrix hexa™ or pentavalent (whole-cell or acellular pertussis) vaccines. Coadministration of Hexyon® with other common childhood vaccines did not affect immune response to any vaccines. Hexyon® has a good reactogenicity/safety profile. The immunogenicity and safety profile of Hexyon® was similar to that of several approved vaccines, including Infanrix hexa™. However, Hexyon® offers the convenience of full-liquid, ready-to-use formulation, which may minimize vaccination errors and preparation time. Thus, Hexyon® is a convenient, useful option for vaccination against childhood diseases caused by six major pathogens.

Abstract licence: CC BY-NC