Lessons learnt from influenza vaccination in immunocompromised children undergoing treatment for cancer

Formulation development of a stable influenza recombinant neuraminidase vaccine candidate

Current influenza vaccines could be augmented by including recombinant neuraminidase (rNA) protein antigen to broaden protective immunity and improve efficacy. Toward this goal, we investigated formulation conditions to optimize rNA physicochemical stability. When rNA in sodium phosphate saline buffer (NaPBS) was frozen and thawed (F/T), the tetrameric structure transitioned from a "closed" to an "open" conformation, negatively impacting functional activity. Hydrogen deuterium exchange experiments identified differences in anchorage binding sites at the base of the open tetramer, offering a structural mechanistic explanation for the change in conformation and decreased functional activity. Change to the open configuration was triggered by the combined stresses of acidic pH and F/T. The desired closed conformation was preserved in a potassium phosphate buffer (KP), minimizing pH drop upon freezing and including 10% sucrose to control F/T stress. Stability was further evaluated in thermal stress studies where changes in conformation were readily detected by ELISA and size exclusion chromatography (SEC). Both tests were suitable indicators of stability and antigenicity and considered potential critical quality attributes (pCQAs). To understand longer-term stability, the pCQA profiles from thermally stressed rNA at 6 months were modeled to predict stability of at least 24-months at 5°C storage. In summary, a desired rNA closed tetramer was maintained by formulation selection and monitoring of pCQAs to produce a stable rNA vaccine candidate. The study highlights the importance of understanding and controlling vaccine protein structural and functional integrity.

Relationship between vaccine hesitancy and vaccination behaviors: Systematic review and meta-analysis of observational studies

BACKGROUND

Vaccination is crucial for prevention of infectious diseases, and identification of the impact of vaccine hesitancy on vaccination programs is crucial for early intervention and formulation of policies to alleviate vaccine hesitancy. The aim of this systematic review was to explore the relationship between vaccine hesitancy and negative vaccination behavior globally.

METHODS

We searched for observational studies in various databases. We conducted a meta-analysis using pooled odds ratios (OR) and 95 % confidence intervals (CI), performed meta regression and subgroup analysis to explore the role factors such as location and individual characteristics on the association between vaccine hesitancy and vaccination behavior.

RESULTS

A total of 46 articles were included in systematic analysis and 34 articles were included in the meta-analysis. The systematic analysis comprised 162,601 samples, whereas the meta-analysis included 147,554 samples. The meta-analysis showed that a higher rate of vaccine hesitancy was associated with an increased likelihood of adverse vaccination behaviors (all adverse behaviors: OR = 1.50, 95 % CI, 1.33-1.70, P < 0.001; unvaccinated: OR = 1.48, 95 % CI, 1.29-1.70, P < 0.001; vaccine delay: OR = 2.61, 95 % CI, 1.97-3.44, P < 0.001). The meta-regression results indicated that the heterogeneity observed was mainly from sample selection methods, age of vaccinees and the health status of participants. The results showed that parents of minor vaccinees or without high-risk health status had a higher association between vaccine hesitancy and vaccine uptake compared with populations exposed to higher health risks or adult vaccinees.

CONCLUSION

The findings provide evidence on the association between vaccine hesitancy and adverse vaccination behaviors. The results showed that these population-specific factors should be considered in future research, and during formulation of interventions and implementation of policies to improve vaccination uptake.

Current vaccination status and safety of children with peripheral neuroblastoma in the real-world

Background

peripheral neuroblastic tumors (pNT) have high incidence and mortality, and infants are prone to various infectious diseases. The purpose of this study is to understand the immunization status of children with pNT in the real-world and the incidence of adverse reactions after vaccination, and to evaluate the feasibility of vaccination and the influencing factors of vaccination.

Methods

Children with pNT treated in the Children's Hospital Affiliated to Zhejiang University from January 1, 2011 to December 1, 2021 were included. By referring to medical records, the vaccination history of the national immunization program (NIP) vaccines and the occurrence of adverse events following immunization(AEFI), current status and safety of immunization in children with pNT in the real-world were analyzed.

Results

Among 784 children with pNT, 394 were able to obtain the history of vaccination. The overall vaccination rate of NIP vaccines was 71.49% before chemotherapy and 37.67% after chemotherapy, and the recovery time of vaccination after treatment was 16.00 (6.00,24.00) months. Age, time of tumor diagnosis and disease classification were significantly correlated with vaccination. AEFI reported an incidence of 0.23‰.

Conclusion

The vaccination rate of children with pNT is generally low, especially the vaccination rate after chemotherapy. The vaccination safety is good, children should be encouraged to immunize.