Adolescent Vaccination Research Articles

Abstract 46: Human Papilloma Virus Vaccination and Its Determinants Among Adolescent Girls Aged 14 Years Old in Hai District of Kilimanjaro Region in Northern Tanzania

Abstract Purpose: Human Papilloma Virus (HPV) vaccination is a key primary prevention method against cervical cancer which is given to young girls before onset of sexual activity. In Tanzania, cervical cancer is the most frequent occurring cancer among women and is the leading cause of cancer mortality. The HPV Vaccination program was rolled-out in Tanzania in 2018 for adolescent girls aged 9-14 years old to receive two doses at a six months interval, with the annual vaccine uptake of 46.1%. In 2019, the uptake of the HPV vaccine was 64%, where as the national coverage target is 75%. This study is aimed at assessing the determinants of HPV vaccination among adolescent girls in Hai district, Kilimanjaro region, northern Tanzania. Methods: A cross-sectional study was conducted between July and August 2020 among 14 years old girls in selected secondary schools within Hai district. Close ended questionnaire interviews were conducted to the girls on the study. Data was analysed using SPSS version 20 and odds ratio was used to assess the association between several factors and HPV vaccination. Results: A total of 301 adolescent girls aged 14 years consented to the study. HPV vaccination uptake was 65% (196). More than three fifth (60.7%, 119) reported to have received the two required doses. Knowledge of HPV (OR = 5.68 95% CI (0.72- 44.96); p-value = 0.01) and HPV vaccine (OR = 20.11 95% CI (10.88- 37.99); p-value = 0.01) contributed significantly to HPV vaccine uptake among the adolescent girls in the study. More than one-third (34.9%, 105) of the participants were not vaccinated, main reasons adduced for not being vaccinated include lack of proper information about HPV vaccine (60.0%), fear of side effects (14%) and parental refusal (11%). Conclusion: HPV vaccination is globally accepted as a pivotal primary prevention means against cervical cancer. Emphasizing dissemination of clear and comprehensible information to the society, especially to the adolescent girls, about HPV, cervical cancer and HPV vaccine will significantly increase HPV vaccination among the adolescent girls. Utilizing health care workers and policy makers in providing such education will facilitate its successful implementation. Citation Format: Jojet Josephat. Human Papilloma Virus Vaccination and Its Determinants Among Adolescent Girls Aged 14 Years Old in Hai District of Kilimanjaro Region in Northern Tanzania [abstract]. In: Proceedings of the 11th Annual Symposium on Global Cancer Research; Closing the Research-to-Implementation Gap; 2023 Apr 4-6. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(6_Suppl):Abstract nr 46.

Coverage evaluation survey of COVID-19 vaccination among adolescents aged 12 to 17 years in the rural field practice area of medical college near Bangalore

Background: COVID-19 vaccination in India was started from 16 January 2021. The vaccination for adolescents was started one year later. The only source of COVID-19 vaccination coverage is government data. There is a lack of external studies on COVID-19 vaccine coverage in this age group. In this regard, the present study was taken up with the objectives to assess the vaccination coverage of COVID-19 among adolescents aged 12-17 years and the factors associated with COVID-19 vaccine hesitancy. Methods: A coverage evaluation survey was done for assessing COVID-19 vaccination coverage among adolescents aged 12 to 17 years from September to December 2022 in the rural field practice area of a medical college near Bangalore. Results: Out of the 420 study subjects, 294 (70%) were fully vaccinated, 70 (16.6%) were partially vaccinated and 56 (13.4%) were unvaccinated. It was observed that the coverage of COVID-19 vaccine in the age group of 15 to 17 years was higher compared to 12 to 14 years. Conclusions: The COVID 19 vaccine coverage with two doses among adolescents aged 12-14 was 61.9% and 78.1% among 210 adolescents aged 15 to 17 years in the rural locality. The most common reason for partial vaccination was that the school did not provide the second dose and the most common reason for not being vaccinated is that the subject was not eligible for vaccination during the school vaccination campaign.

A qualitative study on COVID-19 pandemic impacts on parental attitudes and intentions for routine adolescent vaccinations: The role of trust

IntroductionThe COVID-19 pandemic has contributed to declines in routine childhood and adolescent vaccination coverage globally. While the declines in Australia have been less, they are a concern, given steady increases in coverage prior to the pandemic. Given limited evidence on how the experiences of parents during the pandemic affected their attitudes about and intentions towards adolescent vaccinations, with this study we aimed to explore these. MethodsThis was a qualitative study. We invited parents of adolescents eligible for school-based vaccinations in 2021 from metropolitan, regional and rural areas of New South Wales and Victoria (the most affected States) and South Australia (less affected) to half hour-long online semi-structured interviews. We analysed data thematically and applied a conceptual model of trust in vaccination. ResultsIn July 2022 we interviewed 15 accepting, 4 hesitant and two parents who refused adolescent vaccinations. We identified three themes: 1. Pandemic impacting on professional and personal lives and routine immunisations; 2. Pandemic strengthening preexisting vaccine hesitancy, with perceived lack of clarity in governmental information about vaccination and stigma around non-vaccinating as contributing factors; 3. Pandemic raising awareness of the benefits of COVID-19 and routine vaccinations, with communication campaigns and one’s trusted doctor’s vaccination recommendations as contributing factors. ConclusionsFor some parents, experiences of poor system readiness and growing distrust towards health and vaccination systems strengthened their pre-existing vaccine hesitancy. We offer recommendations on how trust in the health system and immunisation can be optimised post-pandemic to increase uptake of routine vaccines. These include improving access to vaccination services and clear, timely information about vaccines; supporting immunisation providers in their immunisation consultations; working alongside communities, and building capacity of vaccine champions.

Exploring the factors contributing to low vaccination uptake for nationally recommended routine childhood and adolescent vaccines in Kenya

BackgroundVaccination remains the most effective means of reducing the burden of infectious disease among children. It is estimated to prevent between two to three million child deaths annually. However, despite being a successful intervention, basic vaccination coverage remains below the target. About 20 million infants are either under or not fully vaccinated, most of whom are in Sub-Saharan Africa region. In Kenya, the coverage is even lower at 83% than the global average of 86%. The objective of this study is to explore the factors that contribute to low demand or vaccine hesitancy for childhood and adolescent vaccines in Kenya.MethodsThe study used qualitative research design. Key Informant Interviews (KII) was used to obtain information from national and county-level key stakeholders. In-depth Interviews (IDI) was done to collect opinions of caregivers of children 0–23 months and adolescent girls eligible for immunization, and Human papillomavirus (HPV) vaccine respectively. The data was collected at the national level and counties such as Kilifi, Turkana, Nairobi and Kitui. The data was analyzed using thematic content approach. A total of 41 national and county-level immunization officials and caregivers formed the sample.ResultsInsufficient knowledge about vaccines, vaccine supply issues, frequent healthcare worker’s industrial action, poverty, religious beliefs, inadequate vaccination campaigns, distance to vaccination centers, were identified as factors driving low demand or vaccine hesitancy against routine childhood immunization. While factors driving low uptake of the newly introduced HPV vaccine were reported to include misinformation about the vaccine, rumors that the vaccine is a form of female contraception, the suspicion that the vaccine is free and available only to girls, poor knowledge of cervical cancer and benefits of HPV vaccine.ConclusionsRural community sensitization on both routine childhood immunization and HPV vaccine should be key activities post COVID-19 pandemic. Likewise, the use of mainstream and social media outreaches, and vaccine champions could help reduce vaccine hesitancy. The findings are invaluable for informing design of context-specific interventions by national and county-level immunization stakeholders. Further studies on the relationship between attitude towards new vaccines and connection to vaccine hesitancy is necessary.

Safety and immunogenicity of heterologous boosting with orally aerosolised or intramuscular Ad5-nCoV vaccine and homologous boosting with inactivated vaccines (BBIBP-CorV or CoronaVac) in children and adolescents: a randomised, open-label, parallel-controlled, non-inferiority, single-centre study

Heterologous booster immunisation with orally administered aerosolised Ad5-nCoV vaccine (AAd5) has been shown to be safe and highly immunogenic in adults. Here, we aimed to assess the safety and immunogenicity of heterologous booster immunisation with orally administered AAd5 in children and adolescents aged 6-17 years who had received two doses of inactivated vaccine (BBIBP-CorV or CoronaVac). We did a randomised, open-label, parallel-controlled, non-inferiority study to assess the safety and immunogenicity of heterologous booster immunisation with AAd5 (0·1 mL) or intramuscular Ad5-nCoV vaccine (IMAd5; 0·3 mL) and homologous booster immunisation with inactivated vaccine (BBIBP-CorV or CoronaVac; 0·5 mL) in children (aged 6-12 years) and adolescents (aged 13-17 years) who had received two doses of inactivated vaccine at least 3 months earlier in Hunan, China. Children and adolescents who were previously immunised with two-dose BBIBP-CorV or CoronaVac were recruited for eligibility screening at least 3 months after the second dose. A stratified block method was used for randomisation, and participants were stratified by age and randomly assigned (3:1:1) to receive AAd5, IMAd5, or inactivated vaccine. The study staff and participants were not masked to treatment allocation. Laboratory and statistical staff were masked during the study. In this interim analysis, adverse events within 14 days and geometric mean titre (GMT) of serum neutralising antibodies on day 28 after the booster vaccination, based on the per-protocol population, were used as the primary outcomes. The analysis of non-inferiority was based on comparison using a one-sided 97·5% CI with a non-inferiority margin of 0·67. This study was registered at ClinicalTrials.gov, NCT05330871, and is ongoing. Between April 17 and May 28, 2022, 436 participants were screened and 360 were enrolled: 220 received AAd5, 70 received IMAd5, and 70 received inactivated vaccine. Within 14 days after booster vaccination, vaccine-related adverse reactions were reported: 35 adverse events (in 13 [12%] of 110 children and 22 [20%] of 110 adolescents) in 220 individuals in the AAd5 group, 35 (in 18 [51%] of 35 children and 17 [49%] of 35 adolescents) in 70 individuals in the IMAd5 group, and 13 (in five [14%] of 35 children and eight [23%] of 35 adolescents) in 70 individuals in the inactivated vaccine group. Solicited adverse reactions were also reported: 34 (13 [12%] of 110 children and 21 [10%] of 110 adolescents) in 220 individuals in the AAd5 group, 34 (17 [49%] of 35 children and 17 [49%] of 35 adolescents) in 70 individuals in the IMAd5 group, and 12 (five [14%] of 35 children and seven [20%] of 35 adolescents) in 70 individuals in the inactivated vaccine group. The GMTs of neutralising antibodies against ancestral SARS-CoV-2 Wuhan-Hu-1 (Pango lineage B) in the AAd5 group were significantly higher than the GMTs in the inactivated vaccine group (adjusted GMT ratio 10·2 [95% CI 8·0-13·1]; p<0·0001). Our study shows that a heterologous booster with AAd5 is safe and highly immunogenic against ancestral SARS-CoV-2 Wuhan-Hu-1 in children and adolescents. National Key R&D Program of China.

BNT162b2 COVID-19 Vaccines in Children, Adolescents and Young Adults with Cancer-A 1-Year Follow-Up.

(1) Background: Children and young adults with cancer are poorly represented in COVID-19 vaccination studies, and long-term protection conferred by vaccination is not known. (2) Objectives: 1. To determine the adverse effects associated with BNT162B2 vaccination in children and young adults with cancer. 2. To assess its efficacy in stimulating immunological response and in preventing severe COVID-19 disease. (3) Methods: Retrospective single-center study evaluating patients aged 8 to 22 years, with cancer, who underwent vaccination from January 2021 to June 2022. ELISA serologies and serum neutralization were collected monthly from the first injection. Serologies below 26 were considered negative, while those above 264 BAU/mL were considered positive and indicative of protection. Antibodies titers were considered positive above 20. Data on adverse events and infections were collected. (4) Results: 38 patients were included (M/F = 1.7, median age 16 years), of whom 63% had a localized tumor and 76% were undergoing treatment at the time of the first vaccination. Two or three vaccine injections were administered in 90% of patients. Adverse events were mainly systemic and not severe, except for seven grade 3 toxicities. Four cancer-related deaths were reported. Median serology was negative the month following the first vaccination and became protective during the third month. At 3 and 12 months, median serology was 1778 and 6437 BAU/mL, respectively. Serum neutralization was positive in 97% of the patients. COVID-19 infection occurred despite vaccination in 18%; all were mild forms. (5) Conclusions: In children and young adults with cancer, vaccination was well tolerated and conferred effective serum neutralization. COVID-19 infections were mild, and vaccine seroconversion persisted after 12 months in most patients. The value of additional vaccination should be further established.

Leveraging health infrastructure to optimize HPV vaccination for adolescents in Zambia: Protocol for an implementation study.

Cervical cancer is the leading cause of cancer death in Zambia, where HIV prevalence is also high (11.3%). HIV heightens the risk of developing and dying from cervical cancer. The human papillomavirus (HPV) vaccine can prevent 90% of cervical cancers, and in Zambia is recommended for adolescent girls ages 14-15 years, including those with HIV. Currently they mainly deliver HPV vaccination via school-based campaigns, which may exclude the most vulnerable adolescents-those out-of-school or who irregularly attend. Adolescents living with HIV (ALHIV) are more likely to have these vulnerabilities. Further, school-based campaigns are not tailored to the WHO-recommended HPV vaccination schedule for ALHIV (3 versus 2 doses). Integrating HPV vaccination into routine care in adolescent HIV clinics may ensure that ALHIV have access to vaccine at the WHO-recommended schedule. Such integration requires a multilevel approach, stakeholder engagement, and diversified implementation strategies, given known challenges of providing the HPV vaccine in LMICs, including Zambia. Our study aims to integrate HPV vaccination into routine care in adolescent HIV clinics. To achieve success, we will co-design a package of implementation strategies using a previously successful implementation research approach developed for cervical cancer prevention in LMICs: the Integrative Systems Praxis for Implementation Research (INSPIRE). INSPIRE is a novel, comprehensive approach to develop, implement, and evaluate implementation science efforts. Following key elements of INSPIRE, our specific aims are to: 1) Identify the unique multilevel contextual factors (barriers and facilitators) across HIV settings (rural, urban, peri-urban) that influence HPV vaccine uptake; 2) Use Implementation Mapping to translate stakeholder feedback and findings from Aim 1 into a package of implementation strategies to integrate HPV vaccine into HIV clinics; 3) Conduct a Hybrid Type 3 effectiveness-implementation trial to evaluate the package of multilevel implementation strategies for integrating HPV vaccine into HIV clinics. Our research team has strong support, technical expertise, and resources (e.g., vaccines) from the Zambian Ministry of Health; and political will for scale-up. This stakeholder-based implementation model has the potential to be transported to HIV clinics across Zambia and serve as a model to address cancer prevention priorities for those with HIV in other LMICs. To be registered prior to Aim 3, when implementation strategies finalized.

COVID-19 vaccine in adolescents: no new serious safety concerns identified

COVID-19 vaccine in adolescents: no new serious safety concerns identified

Determinants of vaccine hesitancy towards pediatric and adolescent vaccinations and interventions aimed at contrasting that issue in Europe: an overview of systematic reviews

Determinants of vaccine hesitancy towards pediatric and adolescent vaccinations and interventions aimed at contrasting that issue in Europe: an overview of systematic reviews

Human Papillomavirus (HPV) Vaccination Knowledge, Beliefs, and Hesitancy Associated with Stages of Parental Readiness for Adolescent HPV Vaccination: Implications for HPV Vaccination Promotion.

The vaccination against human papillomavirus (HPV) has shown effectiveness in preventing six different types of cancer. Despite a safe, effective HPV vaccine, vaccination coverage for adolescents remains suboptimal, especially in the Memphis, Tennessee metropolitan area. Parents/Guardians have a substantial influence on adolescent vaccination, but little is known about parental cognitive factors contributing to intent on adolescent HPV vaccination in this region. Thus, this study examined factors associated with stages of parental readiness for adolescent HPV vaccination by applying the transtheoretical model. A cross-sectional, online survey was conducted to collect quantitative data on sociodemographic characteristics; health-related information; HPV vaccination knowledge, beliefs, and hesitancy; and stages of readiness for adolescent HPV vaccination among parents. Convenience sampling was performed to recruit a total of 497 parents of adolescents aged 11-17 years in Shelby and Tipton Counties in Tennessee and DeSoto County in Mississippi. Binary logistic regression analyses showed that greater knowledge of HPV vaccination, greater perceived susceptibility to HPV, and lower levels of HPV vaccination hesitancy, respectively, distinguished higher from lower stages of parental readiness for adolescent HPV vaccination after controlling for other variables. The findings provide implications for developing readiness for stage-specific interventions targeted to effectively influence the parental decision-making process regarding HPV vaccination for adolescents.

Safety, Immunogenicity, and Efficacy of the NVX-CoV2373 COVID-19 Vaccine in Adolescents

Greater than 20% of cases and 0.4% of deaths from COVID-19 occur in children. Following demonstration of the safety and efficacy of the adjuvanted, recombinant spike protein vaccine NVX-CoV2373 in adults, the PREVENT-19 trial immediately expanded to adolescents. To evaluate the safety, immunogenicity, and efficacy of NVX-CoV2373 in adolescents. The NVX-CoV2373 vaccine was evaluated in adolescents aged 12 to 17 years in an expansion of PREVENT-19, a phase 3, randomized, observer-blinded, placebo-controlled multicenter clinical trial in the US. Participants were enrolled from April 26 to June 5, 2021, and the study is ongoing. A blinded crossover was implemented after 2 months of safety follow-up to offer active vaccine to all participants. Key exclusion criteria included known previous laboratory-confirmed SARS-CoV-2 infection or known immunosuppression. Of 2304 participants assessed for eligibility, 57 were excluded and 2247 were randomized. Participants were randomized 2:1 to 2 intramuscular injections of NVX-CoV2373 or placebo, 21 days apart. Serologic noninferiority of neutralizing antibody responses compared with those in young adults (aged 18-25 years) in PREVENT-19, protective efficacy against laboratory-confirmed COVID-19, and assessment of reactogenicity and safety. Among 2232 participants (1487 NVX-CoV2373 and 745 placebo recipients), the mean (SD) age was 13.8 (1.4) years, 1172 (52.5%) were male, 1660 (74.4%) were White individuals, and 359 (16.1%) had had a previous SARS-CoV-2 infection at baseline. After vaccination, the ratio of neutralizing antibody geometric mean titers in adolescents compared with those in young adults was 1.5 (95% CI, 1.3-1.7). Twenty mild COVID-19 cases occurred after a median of 64 (IQR, 57-69) days of follow-up, including 6 among NVX-CoV2373 recipients (incidence, 2.90 [95% CI, 1.31-6.46] cases per 100 person-years) and 14 among placebo recipients (incidence, 14.20 [95% CI, 8.42-23.93] cases per 100 person-years), yielding a vaccine efficacy of 79.5% (95% CI, 46.8%-92.1%). Vaccine efficacy for the Delta variant (the only viral variant identified by sequencing [n = 11]) was 82.0% (95% CI, 32.4%-95.2%). Reactogenicity was largely mild to moderate and transient, with a trend toward greater frequency after the second dose of NVX-CoV2373. Serious adverse events were rare and balanced between treatments. No adverse events led to study discontinuation. The findings of this randomized clinical trial indicate that NVX-CoV2373 is safe, immunogenic, and efficacious in preventing COVID-19, including the predominant Delta variant, in adolescents. ClinicalTrials.gov Identifier: NCT04611802.

Decision-Making about COVID-19 Vaccines among Health Care Workers and Their Adolescent Children.

Health care workers promote COVID-19 vaccination for adolescent patients, and as parents, may influence their own children to get vaccinated. We conducted virtual, semi-structured qualitative interviews with vaccinated health care workers and their adolescent children to explore their decision-making process for COVID-19 vaccination. In total, 21 health care workers (physicians, nurses, and medical staff) and their adolescent children (N = 17) participated in interviews. The following three themes described parent-adolescent decision-making for COVID-19 vaccination: (1) family anticipation and hesitation about COVID-19 vaccine approval; (2) parents' or adolescents' choice: the decision maker for adolescent COVID-19 vaccination; and (3) leveraging one's vaccination status to encourage others to get vaccinated. Nurses encouraged adolescent autonomy in decisions for COVID-19 vaccination while physicians viewed vaccination as the parent's decision. Health care workers and their adolescent children used role-modeling to motivate unvaccinated peers and may model their decision-making process for adolescent COVID-19 vaccination with their own children to support their patients' and parents' vaccine decisions.

Long COVID and Hybrid Immunity among Children and Adolescents Post-Delta Variant Infection in Thailand.

This study aimed to assess long COVID, and describe immunogenicity against Omicron variants following BNT162b2 vaccination. A prospective cohort study was conducted among children (aged 5-11) and adolescents (aged 12-17) who had SARS-CoV-2 infection from July to December 2021 (Delta predominant period). Long COVID symptoms were assessed by questionnaires at 3 months after infection. Immunogenicity was evaluated by using a surrogate virus-neutralizing antibody test (sVNT) against the Omicron variant. We enrolled 97 children and 57 adolescents. At 3 months, 30 children (31%) and 34 adolescents (60%) reported at least one long COVID symptom, with respiratory symptoms prevailing (25% children and 32% adolescents). The median time from infection to vaccination was 3 months in adolescents and 7 months in children. At 1 month following vaccination, in children who received one-dose and two-dose BNT162b2 vaccines, the median (IQR) sVNT against Omicron was 86.2% inhibition (71.1-91.8) and 79.2% inhibition (61.5-88.9), respectively (p = 0.26). Among adolescents who received one-dose and two-dose BNT162b2 vaccines, the median (IQR) sVNT against Omicron was 64.4% inhibition (46.8-88.8) and 68.8% inhibition (65.0-91.2) (p = 0.64). Adolescents had a higher prevalence of long COVID than children. Immunogenicity against the Omicron variant after vaccination was high and did not vary between one or two doses of the vaccine in either children or adolescents.

Effectiveness of an inactivated SARS-CoV-2 vaccine in children and adolescents: a large-scale observational study

Policymakers urgently need evidence to adequately balance the costs and benefits of mass vaccination against COVID-19 across all age groups, including children and adolescents. In this study, we aim to assess the effectiveness of CoronaVac's primary series among children and adolescents in Chile. We used a large prospective national cohort of about two million children and adolescents 6-16 years to estimate the effectiveness of an inactivated SARS-CoV-2 vaccine (CoronaVac) in preventing laboratory-confirmed symptomatic SARS-CoV-2 infection (COVID-19), hospitalisation, and admission to an intensive care unit (ICU) associated with COVID-19. We compared the risk of individuals treated with a complete primary immunization schedule (two doses, 28 days apart) with the risk of unvaccinated individuals during the follow-up period. The study was conducted in Chile from June 27, 2021, to January 12, 2022, when the SARS-CoV-2 Delta variant was predominant but other variants of concern were co-circulating, including Omicron. We used inverse probability-weighted survival regression models to estimate hazard ratios of complete immunization over the unvaccinated status, accounting for time-varying vaccination exposure and adjusting for relevant demographic, socioeconomic, and clinical confounders. The estimated adjusted vaccine effectiveness for the inactivated SARS-CoV-2 vaccine in children aged 6-16 years was 74.5% (95% CI, 73.8-75.2), 91.0% (95% CI, 87.8-93.4), 93.8% (95% CI, 87.8-93.4) for the prevention of COVID-19, hospitalisation, and ICU admission, respectively. For the subgroup of children 6-11 years, the vaccine effectiveness was 75.8% (95% CI, 74.7-76.8) for the prevention of COVID-19 and 77.9% (95% CI, 61.5-87.3) for the prevention of hospitalisation. Our results suggest that a complete primary immunization schedule with the inactivated SARS-CoV-2 vaccine provides effective protection against severe COVID-19 disease for children 6-16 years. Agencia Nacional de Investigación y Desarrollo (ANID) Millennium Science Initiative Program and Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP).

COVID-19 Vaccines Are Safely Tolerated in Adolescents with Cutaneous Mastocytosis

Introduction: The management of the COVID-19 vaccine in children with mastocytosis is unclear due to a lack of data. In the current study, we aimed to evaluate the adverse reactions following COVID-19 vaccination in adolescents with cutaneous mastocytosis (CM). Methods: This study included 27 paediatric patients who were diagnosed with CM and were followed up in the paediatric allergy department of a tertiary care children’s hospital. Results: The median (IQR) age of the patients at the time of COVID-19 vaccination was 180 (156–203) months. Forty-four per cent of patients were vaccinated with the COVID-19 vaccine. Among all participants, the vaccination rate was found to be higher in older children, those who had been diagnosed with MPCM, and those who had not been infected with COVID-19 (p = 0.019, p = 0.009, p = 0.002, respectively). A total of 23 doses of the COVID-19 vaccine, including two doses of Sinovac/CoronaVac and 21 doses of Pfizer/BioNTech, were administered to 12 paediatric patients with CM. One of the patients had a history of intense itch, erythematous urticarial plaques, and had an exacerbation of existing skin lesions within 24–48 h after both doses of Pfizer/BioNTech vaccination. Conclusion: The COVID-19 vaccination of patients with CM in this series seems to be safe, and the rate of adverse events was comparable to that in the general population. These results found in adolescents with CM are in line with the existing evidence that CM does not preclude vaccination in children.

Hybrid immunity against reinfection with SARS-CoV-2 following a previous SARS-CoV-2 infection and single dose of the BNT162b2 vaccine in children and adolescents: a target trial emulation

Although most children and adolescents have had a previous SARS-CoV-2 infection and many continue to receive COVID-19 vaccinations, studies of the effectiveness of hybrid immunity against reinfection with the omicron (B.1.1.529) variant are scarce. We aimed to examine the effectiveness of vaccination in convalescent children and adolescents against reinfection with the delta (B.1.617.2) variant and the BA.1 and BA.2 and BA.4 and BA.5 omicron subvariants. This retrospective cohort study was devised to emulate a target randomised control trial using a retrospective dataset of anonymised health records of children (5-11 years old) and adolescents (12-16 years old) who were members of the Maccabi Healthcare Services, Israel. The design emulated 91 randomised trials by devising a series of multiple nested trials, compiling the results into a single dataset, and fitting Cox proportional hazards models to estimate adjusted hazard ratios (HRs) with 95% CIs of each measured outcome. The primary aim was to assess the protection from reinfection with the delta variant and the BA.1 and BA.2 and BA.4 and BA.5 omicron subvariants associated with hybrid immunity as a result of a previous SARS-CoV-2 infection followed by vaccination with the BNT162b2 (Pfizer-BioNTech) vaccine. Data from between from March 1, 2020, to July 31, 2022, for 163 812 individuals (120 721 children [59 404 girls and 61 317 boys], median age 8·0 years [IQR 6·7 to 10·2]; and 43 091 adolescents [21 239 girls and 21 852 boys], median age 13·5 years [12·6 to 14·8]) were included in at least one trial. A single dose of the BNT162b2 vaccine in convalescent children and adolescents confers statistically significant protection against the delta variant (78% [95% CI 72 to 83] in adolescents and 64% [3 to 87] in children) and the omicron BA.1 and BA.2 subvariants (54% [50 to 57] in adolescents and 71% [67 to 73] in children) compared with children who had a previous infection but were unvaccinated. However, the vaccine was not found to confer statistically significant protection against the BA.4 and BA.5 omicron subvariants in adolescents (8% [-18 to 29]) and children (12% [-6 to 27]). Decision makers in BA.4 and BA.5 dominant regions should re-examine whether convalescent individuals aged 5-16 years should receive the BNT162b2 vaccine to prevent future reinfection, especially in light of reports that show that most children and adolescents have already been infected with SARS-CoV-2. None.

Safety and Immunogenicity Following the Second and Third Doses of the BNT162b2 mRNA COVID-19 Vaccine in Adolescents with Juvenile-Onset Autoimmune Inflammatory Rheumatic Diseases: A Prospective Multicentre Study.

To explore the long-term safety and dynamics of the immune response induced by the second and third doses of the BNT162b2 mRNA COVID-19 vaccine in adolescents with juvenile-onset autoimmune inflammatory rheumatic diseases (AIIRDs) compared with healthy controls. This international prospective study included adolescents with AIIRDs and controls vaccinated with two (AIIRDs n = 124; controls n = 80) or three (AIIRDs n = 64; controls n = 30) doses of the BNT162b2 vaccine, evaluated for vaccine side-effects, disease activity, COVID-19 breakthrough infection rates and severity, and anti-spike S1/S2 IgG antibody titers in a sample from both groups. The vaccination safety profile was favorable, with most patients reporting mild or no side-effects. The rheumatic disease remained stable at 98% and 100% after the second and third doses, respectively. The two-dose vaccine induced comparable seropositivity rates among patients (91%) and controls (100%), (p = 0.55), which declined within 6 months to 87% and 100%, respectively (p = 0.3) and increased to 100% in both groups after the third vaccine dose. The overall post-vaccination COVID-19 infection rate was comparable between patients and controls, 47.6% (n = 59) and 35% (n = 28), respectively; p = 0.5278, with most infections occurring during the Omicron surge. In relation to the last vaccination, time-to-COVID-19 infection was similar between patients and controls, at a median of 5.5 vs. 5.2 months, respectively (log-rank p = 0.1555). The safety profile of three doses of the BNT162b2 mRNA vaccine was excellent, with adequate humoral response and similar efficacy among patients and controls. These results support the recommendation for vaccinating adolescents with juvenile-onset AIIRDs against COVID-19.

Effectiveness of BNT162b2 COVID-19 Vaccination in Children and Adolescents.

We assessed BNT162b2 vaccine effectiveness (VE) against mild to moderate and severe coronavirus disease 2019 (COVID-19) in children and adolescents through the Omicron BA.4/BA.5 period. Using VISION Network records from April 2021 to September 2022, we conducted a test-negative, case-control study assessing VE against COVID-19-associated emergency department/urgent care (ED/UC) encounters and hospitalizations using logistic regression, conditioned on month and site, adjusted for covariates. We compared 9800 ED/UC cases with 70 232 controls, and 305 hospitalized cases with 2612 controls. During Delta, 2-dose VE against ED/UC encounters at 12 to 15 years was initially 93% (95% confidence interval 89 to 95), waning to 77% (69% to 84%) after ≥150 days. At ages 16 to 17, VE was initially 93% (86% to 97%), waning to 72% (63% to 79%) after ≥150 days. During Omicron, VE at ages 12 to 15 was initially 64% (44% to 77%), waning to 13% (3% to 23%) after ≥150 days; at ages 16 to 17 VE was 31% (10% to 47%) during days 60 to 149, waning to 7% (-8 to 20%) after 150 days. A monovalent booster increased VE to 54% (40% to 65%) at ages 12 to 15 and 46% (30% to 58%) at ages 16 to 17. At ages 5 to 11, 2-dose VE was 49% (33% to 61%) initially and 41% (29% to 51%) after 150 days. During Delta, VE against hospitalizations at ages 12 to 17 was high (>97%), and at ages 16 to 17 remained 98% (73% to 100%) beyond 150 days; during Omicron, hospitalizations were too infrequent to precisely estimate VE. BNT162b2 protected children and adolescents against mild to moderate and severe COVID-19. VE was lower during Omicron predominance including BA.4/BA.5, waned after dose 2 but increased after a monovalent booster. Children and adolescents should receive all recommended COVID-19 vaccinations.

Awareness of HPV and HPV vaccines, acceptance to vaccination and its influence factors among parents of adolescents 9 to 18 years of age in China: A cross-sectional study

BackgroundVaccination uptake rates for adolescents are still low in China despite safe and effective human papillomavirus vaccines being available. The awareness and attitudes of parents to HPV vaccines play a decisive role in adolescents' HPV vaccination uptake. MethodsA cross-sectional study was conducted from March, 2022 to May, 2022 using an anonymous questionnaire among parents of 9 to 18 years of age from 73 cities in 23 provinces in mainland China. Demographic characteristics of parents, their knowledge and attitudes about HPV and HPV vaccination, as well as factors influencing HPV vaccination in adolescents were assessed. ResultsMore than two-thirds of parents heard of HPV (75.5%) and HPV vaccines (84.7%). Of these participants, mothers (83.8%) were in the majority. Parents willing to vaccinate themselves and their children against HPV were 84.9% and 87.6%, respectively. Parents were more likely to vaccinate their daughters against HPV than their sons (P < 0.001). Parents who had heard of the HPV vaccines (P = 0.028) or had vaccinated themselves (P < 0.001) were more likely to have HPV vaccination for their children. Parents who accepted the price of the HPV vaccines (P = 0.005) were more likely to have their children vaccinated against HPV. ConclusionsChildren's gender, awareness of the HPV vaccines, parental HPV vaccination, and the price of the HPV vaccines are likely to be the reason for parents' vaccine hesitancy for adolescents. Practice implicationsNurses have a critical role in identifying parental hesitancy and providing individualized education to expand the parental awareness and knowledge and encourage on-time adolescents vaccination.

Abstract 721: Vaccination barriers for HPV vaccine initiation and completion: A perception analysis using the Association of Immunization Managers annual survey

Abstract Background: Human Papillomavirus (HPV) is the most common sexually transmitted infection in the United States of America (USA) and it is associated with six types of cancers. Vaccines that protect against HPV infection have been introduced since 2006. Despite many national efforts, vaccination rates remain under 80% and many individual and systematic barriers influence HPV vaccine uptake and completion. Addressing the stem of these barriers at a national level and their regional differences, will help in understanding necessary policies for the acceptance of HPV vaccine. Objective: This study aims to describe the frequency of immunization program managers’ perceptions of the most relevant barriers to HPV vaccination in each national jurisdiction. Methods: Immunization Program Managers (IPMs) in the USA were surveyed from August 2021 to February 2022 as part of the Implementation of School-Entry Policies for Papilloma Virus Vaccination (HPV-PIVac) study with the collaboration of the Association of Immunization Managers. We gathered IPMs perceptions on the most relevant barriers to HPV vaccination within their jurisdiction. Four vaccine barriers were evaluated; for each one, IPMs reported the level (moderate, significant, no barrier) in a three-item scale. The three-item scale was merged into a two-item scale (low/high) and multiple answers from the same state were grouped. Descriptive analysis was performed for each question and results were mapped. Fisher’s exact test was performed to determine the relation between barriers. IPMs that refused or didn’t know their jurisdiction’s barriers were removed from the analysis. Results: 49 IPMs from 31 states and territories participated, resulting in a 53.4% participation rate. For the cost barrier to complete HPV vaccination of children, most IPMs perceived low barriers (51.7%) within their jurisdiction. For the perception of geographical difficulties to complete HPV vaccination, higher barriers (67.9%) were reported among participants. Limited number of providers offering the HPV vaccine was perceived equally as low or high level (50.0%), whereas lack of a strong provider recommendation or failure of providers to discuss and strongly recommend the HPV vaccine was the most significant barrier with a higher level (96.7%). Fisher’s exact test indicated independency between all barriers (p&amp;gt;0.05). For most variables, the Western region reported a greater level of barriers. Conclusion: This analysis documents the IPMs perception of prevalent HPV vaccine barriers for vaccine initiation and completion nationally. These results confirmed the need of further engagement for the accessibility of the vaccine, as preliminary data from NIS-Teen 2021 shows an average adolescent HPV vaccine initiation and UTD coverage of 78.2 and 62.7, respectfully. Funding: NCI Grant #R01CA232743 Citation Format: Alondra Katerina Mercado-Andino, Erick L. Suárez-Pérez, Olga L. Díaz-Miranda, Diana T. Medina-Labees, Ana P. Ortiz, Katelyn Wells, Vivian Colón-López. Vaccination barriers for HPV vaccine initiation and completion: A perception analysis using the Association of Immunization Managers annual survey [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 721.