Behavioral and Cultural Insights, a Nationwide Study Based on Repetitive Surveys of WHO Behavioral Insights Tool in Greece Regarding COVID-19 Pandemic and Vaccine Acceptance

Monitoring behavioral and cultural insights during the pandemic is a useful tool to identify factors related to COVID-19 vaccine acceptance and confront the pandemic’s vast impact. Data were collected using a questionnaire designed according to the “survey tool and guidance” provided by the World Health Organization (WHO). Surveys were conducted by a market research company for five consecutive months, with a sample of 1000 individuals recruited per survey. Vaccination acceptance increased from 55.2% to 67.2%, while the percentage of undecisive individuals decreased from 16.3% to 10.6%. The proportion of vaccine resistant participants remained relatively steady (25–30%). Knowledge about the pandemic and compliance with preventive measures was high (>90%). Factors associated with vaccination included: Increased age, male gender, influenza vaccination, following authorities’ recommendations, being informed by HCWs or formal information sources, care for others, concern about the country’s economic recession and health system overload. Pandemic fatigue was reflected across the surveys, indicated by a decrease in the intention to self-isolate and remain at home when ill. Despite the decrease of undecisive individuals, a firm core of vaccine resistant individuals may be responsible for the relatively lower vaccine coverage compared to northern EU countries. Study results could be useful for developing approaches tailored to a reluctant population

Intensity of Humoral Immune Responses, Adverse Reactions, and Post-Vaccination Morbidity after Adenovirus Vector-Based and mRNA Anti-COVID-19 Vaccines

The aim of the study was to compare mRNA vaccine BNT162b2 with adenovirus vector- based vaccines in terms of presence of adverse reactions, immunogenicity, and protection against COVID-19. A total of 270 individuals were enrolled, of which 135 were vaccinated with adenovirus vector-based vaccines and compared with 135 age- and sex-matched participants who received the BNT162b2 mRNA vaccine. Serum sampling was performed on all participants on days 21, 42, 90, and 180 following the first dose, to evaluate anti-spike IgG and IgA responses. Antibodies were quantified by chemiluminescent microplate and ELISA assays. We demonstrate that both mRNA and adenovirus vector-based vaccines caused mild side-effects and were effective in inducing adequate antibody responses against SARS-CoV-2, although BNT162b2 was superior concerning the intensity of antibody responses and protection against severe COVID-19. Moreover, we identify that IgG and IgA responses depended primarily on both history of previous COVID-19 infection and vaccination platform used, with individuals immunized with a single-dose vaccine having lower antibody titers over time. Lastly, all vaccine platforms had limited side-effects, with the most frequent pain at the injection site. Our results provide useful information regarding antibody responses after vaccination with different vaccine platforms, which can be useful for public health vaccination strategies

TACI Mutations in Primary Antibody Deficiencies: A Nationwide Study in Greece

Background and objectives: Monoallelic (heterozygous) or biallelic (homozygous or compound heterozygous) TACI mutations have been reported as the most common genetic defects in patients with common variable immunodeficiency (CVID), which is the most common clinically significant primary immunodeficiency in humans. The aim of our study was to evaluate the prevalence and any correlations of TACI defects in Greek patients with primary antibody deficiencies. Materials and Methods: 117 patients (male/female: 53/64) with CVID (110) and a combined IgA and IgG subclass deficiency (7) with a CVID-like clinical phenotype were enrolled in the study. Genomic DNA was extracted from peripheral blood and the molecular analysis of the TACI gene was performed by PCR (Polymerase Chain Reaction) and sequencing of all 5 exons, including exon-intron boundaries. Results: Seventeen patients (14.5%) displayed TACI defects, four (23.5%) carried combined heterozygous mutations and 13 (76.5%) carried single heterozygous mutations. The most frequently detected mutation was C104R (58.8%), followed by I87N (23.5%) and A181E (11.8%), while R20C, C62Y, P151L, K188M and E236X mutations were present in only one patient each. Patients with TACI defects were more frequently male (p = 0.011) and displayed a benign lymphoproliferation (splenomegaly and lymph node enlargement, p = 0.047 and p = 0.002, respectively), had a history of tonsillectomy (p = 0.015) and adenoidectomy (p = 0.031) and more frequently exhibited autoimmune cytopenias (p = 0.046). Conclusions: Considering that accumulating evidence suggests several CVID patients have a complex rather than a monogenic inheritance, our data further support the notion that TACI mutations, particularly as monoallelic defects, should be primarily considered as susceptibility co-factors and/or modifiers of primary antibody deficiencies