Adherence to pneumococcal conjugate vaccination schedule and uptake rate as compared to the established diphtheria-tetanus-acellular pertussis vaccination in Cyprus

Immunization strategies for individuals with sickle cell anemia: A narrative review

Sickle cell anemia (SCA) is a hereditary blood disorder characterized by the production of abnormal hemoglobin, leading to the formation of sickle-shaped red blood cells. These distorted cells can obstruct blood flow, causing vaso-occlusive crises and increasing the risk of severe infections due to functional asplenia and immune system dysregulation. Immunization is a crucial strategy to mitigate infection-related complications in individuals with SCA, necessitating a comprehensive and tailored vaccination approach. Current immunization guidelines for individuals with SCA recommend a combination of standard and additional vaccines to address their heightened susceptibility to infections. Key vaccines include pneumococcal conjugate (PCV13) and polysaccharide (PPSV23) vaccines, meningococcal conjugate (MenACWY) and serogroup B (MenB) vaccines, Haemophilus influenzae type b (Hib) vaccine, annual influenza vaccine, and hepatitis A and B vaccines. These vaccinations aim to provide broad protection against pathogens that pose significant risks to patients with SCA. Despite generally adequate immune responses, the variability in vaccine efficacy due to immune dysfunction necessitates booster doses and additional vaccinations. This narrative review highlights the importance of adhering to current immunization recommendations and addresses challenges such as access to care, vaccine hesitancy, and monitoring vaccination status.

Factors Associated with the Uptake of Rotavirus and Pneumococcal Conjugate Vaccines among Children in Armenia: Implications for Future New Vaccine Introductions

Advances in vaccinology have resulted in various new vaccines being introduced into recommended immunization schedules. Armenia introduced the rotavirus vaccine (RV) and the pneumococcal conjugate vaccine (PCV) into its national schedule in 2012 and 2014, respectively. Using data from the Armenia Demographic and Health Survey, the uptake of the RV and the PCV among children aged younger than three years was estimated. Multilevel logistic regression models were used to evaluate individual- and community-level factors associated with uptake. Intra-cluster correlations were estimated to explain variations in uptake between clusters. The uptake proportionof each RV dose were 90.0% and 86.6%, while each PCV dose had values of 83.5%, 79.4%, and 75.5%, respectively. Non-uptake was highest among children less than 6 months old, children with one sibling, children from a wealthy family, or children whose living distance to a health clinic was problematic. Significant variability in non-uptake due to cluster differences was found for both RV doses (30.5% and 22.8%, respectively) and for the second PCV dose (53.9%). When developing strategies for new vaccine implementation, characteristics of the child, such as age, siblingship, and distance to a health clinic or residence, should be considered. Further exploration of cluster differences may provide insights based on the increased uptake of these and other new vaccines.

Childhood COVID-19 vaccine acceptance and preference from caregivers and healthcare workers in China: A survey experiment

With approval of more COVID-19 vaccines for children, vaccine attributes may influence parental acceptance and choices. We aimed to assess effects of vaccine attributes and information on herd immunity on childhood COVID-19 vaccine acceptance. A survey experiment was conducted with caregivers of children aged 6 months to 11 years old and health care workers (HCWs) in China from September 14 to November 18, 2021. Respondents were randomly assigned to receive differing information on herd immunity (> 80% of the entire population must be vaccinated; or no information). Respondents then completed eight discrete choice tasks to assess vaccine acceptance based on attributes. 2331 (90.07%) of 2588 surveyed caregivers and 1576 (92.71%) of 1700 surveyed HCWs would accept COVID-19 vaccination for children, respectively. High Odds Ratios (OR) were found for acceptance of a vaccine with 90% over 50% efficacy (OR 6.70 [95% CI 6.11-7.35] for caregivers; 11.44 [10.12-12.95] for HCWs); and risk of adverse reactions to be 1 over 10 in 10,000 (3.96 [3.72-4.22] for caregivers; 2.98 [2.76-3.22] for HCWs). To achieve herd immunity target (> 80% vaccination coverage), vaccine efficacy should reach over 70% and risk of adverse reactions lower than 1 in 10,000. Knowledge on herd immunity target increased the odds of vaccine acceptance (1.82 [1.34-2.46] for caregivers; 2.42 [1.58-3.72] for HCWs). Childhood COVID-19 vaccine acceptance was high in China, independent of child's age, and depended on vaccine attributes.

Fatal outcomes following immunization errors as reported to the EudraVigilance: A case series

BACKGROUND

Serious adverse reactions after immunization are rare but do occur. In very rare instances, cases with fatal outcome have been reported. These reports can have a huge impact and even more so when due to an immunization error. The aim of this study is to systematically review immunization errors with fatal outcomes in EudraVigilance.

METHODS

This was a case-series analysis of Individual Case Safety Reports (ICSRs) reporting immunization errors and a fatal outcome. To determine the level of certainty of a causal association between the immunization errors and fatal outcomes two independent reviewers assessed all ICSRs using the WHO tool "Causality assessment of an Adverse Event Following Immunization (AEFI)". In accordance with the tool, the ICSRs were classified as consistent, indeterminate, inconsistent/coincidental, or unclassifiable. In addition, we estimated the contribution of reported errors to the fatal outcomes as large, moderate, small, none, or unclassifiable using a classification developed for this study.

RESULTS

A total of 154 ICSRs met the inclusion criteria. Vaccines reported most frequently were pneumococcal (33), rabies (27) and influenza vaccines (24). Most frequently reported errors were non-compliance with recommended schedules of immunization (63). The most frequently reported vaccine-error combination was rabies vaccines and non-compliance with a recommended schedule of immunization (23). Twelve cases were classified as consistent with causal association and had a large error contribution. These cases concerned a cluster of six cases reporting incorrect handling of multi-dose vials containing measles vaccine and six cases reporting administration of live-attenuated vaccines to immunocompromised patients.

DISCUSSION

In this study, we showed that fatal outcomes following immunization errors are very rare. Four key issues were the importance of: (1) quality control of multi-dose vaccines, (2) screening patients for immunocompromising factors, (3) education on the importance of adherence, and (4) measures to improve distinction between vaccines and medicines.

Compliance with vaccination schedules

Childhood immunization is amongst the most cost-effective public health interventions for reducing children's morbidity and mortality. Vaccination coverage is commonly used to assess the vaccination status of a community. Adherence to schedule is critical for providing maximum effectiveness against vaccine-preventable diseases in the community. This is of paramount importance for diseases that are continuously circulating because they can cause large outbreaks. All stakeholders (public health administrators and vaccination providers) should work together in order to increase both vaccination coverage and adherence to schedule. They have to improve the infrastructure used for delivering vaccines, train the health care professionals and finally raise the awareness of the importance of vaccines among parents.