Immunogenicity of the BNT162b2 mRNA Covid-19 vaccine in elderly people over 85 years of age in Greece: the GREVAXIMO study.

BACKGROUND: Elderly people aged over 85 years were among the first groups to receive the BNT162b2 mRNA Covid-19 vaccine in Greece according to the national priority assignment policy. AIM: The aim of this study was to provide useful insight into the antibody generation taking place post-immunization in elderly individuals aged over 85. METHODS: In the first phase of our study, antibody levels were monitored in a total of 400 participants, while our final sample consisted of 297 subjects. Humoral immune responses were recorded in 69.75% (95% CI 65.25-74.25) of vaccinees post-first dose and in 98.99% (95% CI 97.85-100) post-second dose. RESULTS: Overall, a remarkable 40-fold change in IgG levels was observed between the two doses. Subjects displaying low antibody levels after the first dose had significantly higher IgG fold changes than vaccinees whose initial antibody levels were high. CONCLUSION: Taken together, our findings highlighted the high fold change (41.18) recorded in the titers of neutralizing antibodies after the second dose suggesting the need for its timely administration to elderly individuals.

Molecular epidemiology of noroviruses in Northern Greece, 2005-2006.

Noroviruses (NoVs) are important human pathogens associated with acute viral gastroenteritis worldwide, displaying significant genetic heterogeneity. Genotype GII.4 is responsible for the majority of outbreaks reported to date. A total of 460 faecal samples from sporadic gastroenteritis cases were screened for the presence of NoV RNA. Four additional human samples collected during a waterborne NoV gastroenteritis outbreak observed in 2005 in northern Greece, were also included in the study. All PCR-positive samples were tested further using a multiplex RT-PCR, which targets the viral capsid VP1 region D. PCR products from all outbreak samples and from 20 randomly selected samples were sequenced. Phylogenetic analysis revealed that GII.4 genotype predominated (70%), while genotypes GII.2 (10%), GII.7 (15%), and GI.1 (5%) were also detected. All the outbreak NoV strains belonged to the GI.1 genotype. The present study provides a first insight into the epidemiology and genetic diversity of NoVs in Greece and shows that various strains are circulating in the country and cause sporadic cases or outbreaks.

Immunogenicity after the first dose of the BNT162b2 mRNA Covid-19 vaccine: real-world evidence from Greek healthcare workers.

Real-world data regarding the effectiveness, safety and immunogenicity of the Pfizer-BioNTech BNT162b2 mRNA vaccine are accumulating in the literature, suggesting that this vaccine generates high titres of S1-binding IgG antibodies that exhibit potent virus neutralization capacity. This is the first phase IV immunogenicity study to recruit a large number of Greek healthcare workers (n=425) including 63 previously-infected subjects. We measured titres of neutralizing IgGs against the receptor-binding domain of the S1 subunit of the spike protein of SARS-CoV-2 14 days post-immunization with the first dose, employing the SARS-CoV-2 IgG II Quant assay. A total of 92.24 % of our study cohort received a positive assay outcome and titres varied with age. Post-hoc analysis revealed that although titres did not significantly differ among participants aged 20-49 years, a significant decline was marked in the age group of 50-59 years, which was further accentuated in subjects aged over 60. Antibody titres escalated significantly among the previously-infected, indicating the potential booster effect of the first dose in that group.

Second dose of the BNT162b2 mRNA vaccine: Value of timely administration but questionable necessity among the seropositive.

This study monitored titers of neutralizing IgG against the receptor-binding domain of the SARS-CoV-2 S1 subunit 14 days post-injection of each dose of the BNT162b2 mRNA Covid-19 vaccine in 401 Greek healthcare workers aged 20-67. After the first dose, titers varied upon age and history of infection, being lower in the 50+ age group and significantly higher among the seropositive. After the second dose, immunogenicity was significantly boosted in the age 50+ and SARS-CoV-2-naïve individuals, indicating the effectuality of its timely administration, yet questioning its value among the seropositive.

Corynebacterium jeikeium bacteremia in a hemodialyzed patient.

Corynebacterium jeikeium, frequently encountered in clinical specimens, is part of the normal skin flora. Nevertheless, a few cases of C. jeikeium bacteremia followed by severe clinical manifestations have been reported. C. jeikeium has been reported to cause endocarditis, septicemia, meningitis, pneumonia and osteomyelitis, along with soft tissue and trauma infections. Herein we describe a case of C. jeikeium bacteremia in Greece. The isolation of a coryneform bacterium from a clinical specimen should not immediately be considered a superinfection by the skin flora. Clinical and laboratory investigations are essential in order to evaluate such cases before applying appropriate treatment. On the other hand, the association of coryneform bacteria and disease should be critically investigated, with a thorough identification of the strain, ideally beyond the classical methods, at a specialized center.