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.

HPV knowledge and vaccine acceptability: a survey-based study among parents of adolescents (KAPPAS study).

BACKGROUND: Human papillomavirus (HPV) infection is recognized as one of the major causes of infection-related cancer worldwide. In Spain, the HPV vaccination program started in 2007 and until 2022, it targeted 12-year-old girls. METHODS: This was a cross-sectional, multicenter survey-based research carried out at 24 pediatric offices to describe HPV knowledge and vaccine acceptability in parents of children aged between 9 and 14 years-old in Spain. Parents were randomly selected from the medical records following specific quotas to ensure representativeness. The survey included five sections that aim to collect information about sociodemographic characteristics, knowledge of HPV, knowledge and acceptability of vaccines in general, HPV vaccination knowledge and HPV vaccine acceptability. Each section was constituted by a number of close questions with different answer options. Specific scores were assigned to each possible answer to these questions. Based on these scores, four composite variables were created to assess HPV knowledge, HPV vaccine knowledge, HPV vaccine acceptability and vaccines knowledge and acceptability in general. A latent class analysis was performed to identify different group of respondents according to their HPV vaccine acceptability. RESULTS: A total of 1405 valid surveys were included, with 86.19% of the respondents being mothers. The mean score of HPV knowledge was 28.92 out of 40 (maximum value) (95% CI 28.70-29.20) and the mean score of HPV vaccine acceptability was 3.37 out of 5 (maximum value). One third of parents still need more information to take a final decision about HPV vaccination in their children. Parents perceived that females were more likely to become infected than males and tended to associate HPV infection mainly with cervical cancer, showing a. a lack of information about other HPV-related diseases affecting males. CONCLUSIONS: This study results highlight the need for future actions and educational initiatives to raise awareness of HPV consequences in both genders and to contribute to achieving the elimination of HPV-related diseases beyond cervical cancer.

Impact of maternal diphtheria-tetanus-acellular pertussis vaccination on pertussis booster immune responses in toddlers: Follow-up of a randomized trial.

BACKGROUND: Transplacentally transferred antibodies induced by maternal pertussis vaccination interfere with infant immune responses to pertussis primary vaccination. We evaluated whether this interference remains in toddlers after booster vaccination. METHODS: In a prior phase IV, observer-blind, placebo-controlled, randomized study (NCT02377349), pregnant women in Australia, Canada and Europe received intramuscular tetanus-reduced-antigen-content diphtheria-three-component acellular pertussis vaccine (Tdap group) or placebo (control group) at 270/7-366/7 weeks' gestation, with crossover immunization postpartum. Their infants were primed (study NCT02422264) and boosted (at 11-18 months; current study NCT02853929) with diphtheria-tetanus-three-component acellular pertussis-hepatitis B virus-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTaP-HepB-IPV/Hib) and 13-valent pneumococcal conjugate vaccine. Immunogenicity before and after booster vaccination, and reactogenicity and safety of the booster were evaluated descriptively. RESULTS: 263 (Tdap group) and 277 (control group) toddlers received a DTaP-HepB-IPV/Hib booster. Pre-booster vaccination, observed geometric mean concentrations (GMCs) for the three pertussis antigens and diphtheria were 1.4-1.5-fold higher in controls than in the Tdap group. No differences were observed for the other DTaP-HepB-IPV/Hib antigens. One month post-booster vaccination, booster response rates for pertussis antigens were ≥ 92.1% and seroprotection rates for the other DTaP-HepB-IPV/Hib antigens were ≥ 99.2% in both groups (primary objective). Higher post-booster GMCs were observed in controls versus the Tdap group for anti-filamentous hemagglutinin (1.2-fold), anti-pertussis toxoid (1.5-fold) and anti-diphtheria (1.4-fold). GMCs for the other DTaP-HepB-IPV/Hib antigens were similar between groups. Serious adverse events were reported for three toddlers (controls, not vaccination-related). One death occurred pre-booster (Tdap group, not vaccination-related). CONCLUSIONS: As a consequence of interference of maternal pertussis antibodies with infant immune responses to pertussis primary vaccination, pertussis antibody concentrations were still lower in toddlers from Tdap-vaccinated mothers before DTaP-HepB-IPV/Hib booster vaccination. After the booster, antibody concentrations were lower for filamentous hemagglutinin and pertussis toxoid but not for pertactin. The clinical significance of this interference requires further evaluation. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02853929.

Correction to: HPV knowledge and vaccine acceptance among European adolescents and their parents: a systematic literature review.

[This corrects the article DOI: 10.1186/s40985-020-00126-5.].

HPV knowledge and vaccine acceptance among European adolescents and their parents: a systematic literature review.

BACKGROUND: Since the introduction of HPV vaccines, several studies have been conducted in different countries to assess HPV knowledge and vaccine acceptance. The aim of this study was to perform a systematic literature review to summarize results and identify factors associated with HPV knowledge and vaccine acceptance in adolescents and their parents and to compile the measurement tools used in the published research studies performed in European countries where HPV is licensed. METHODS: A systematic literature review was conducted for studies published between January 1st 2006 and December 31st 2017. RESULTS: Seventy non-interventional studies performed in 16 European countries met the inclusion criteria. Thirty-eight of them reported data on HPV knowledge and 40 reported data on HPV vaccine acceptance. Further, 51.8% of adolescents (range 0% to 98.6%) and 64.4% of parents (range 1.7% to 99.3%) knew about HPV infection. Insufficient information and safety concerns were the main barriers to vaccination acceptance. CONCLUSION: HPV knowledge and vaccine acceptance are still modest and vary widely between studies across EU countries. Coordinated efforts should be made to provide the relevant population with information for informed decision-making about HPV vaccination.