COVID-19 vaccine responses are influenced by distinct risk factors in naive and SARS-CoV-2 experienced hemodialysis recipients.

Background: Clinical risk factors of deficient immune responses to COVID-19 mRNA vaccination in SARS-CoV-2 naive hemodialysis recipients (HDR) have already been identified. Clinical factors influencing hybrid immunity induced by SARS-CoV-2 infection and vaccination in HDR have not been reported.

Methods: A comprehensive analysis of antibody (Ab) and T cell responses to two doses of BNT162b2 mRNA vaccination was performed in 103 HDR, including 75 SARS-CoV-2 naive and 28 experienced patients, and in 106 healthy controls (HC) not undergoing HD, including 40 SARS-CoV-2 naive and 66 experienced subjects.

Persistent defect in SARS-CoV-2 humoral and cellular immunity in lung transplant recipients.

Lung transplant recipients (LTRs) are susceptible to severe Coronavirus Disease 2019 (COVID-19) and had lower immune responses to primary severe acute respiratory syndrome-related to coronavirus 2 (SARS-CoV-2) vaccination as compared to the general population and to other solid organ transplant recipients. As immunity induced by booster vaccination and natural infection has increased since the beginning of the pandemic in the general population, immunity acquired by LTRs is not well documented. Humoral and cellular immunity to SARS-CoV-2 was monitored in February and May 2023 in 30 LTRs and compared to that of health care workers (HCWs) and nursing home residents (NHRs).

Third dose of COVID-19 mRNA vaccine closes the gap in immune response between naïve nursing home residents and healthy adults.

Background: Nursing home residents, a frail and old population group, respond poorly to primary mRNA COVID-19 vaccination. A third dose has been shown to boost protection against severe disease and death in this immunosenescent population, but limited data is available on the immune responses it induces.

Methods: In this observational cohort study, peak humoral and cellular immune responses were compared 28 days after the second and third doses of the BNT162b2 mRNA COVID-19 vaccine in residents and staff members of two Belgian nursing homes.

Safety and immunogenicity of a reduced dose of the BNT162b2 mRNA COVID-19 vaccine (REDU-VAC): A single blind, randomized, non-inferiority trial.

Fractional dosing of COVID-19 vaccines could accelerate vaccination rates in low-income countries. Dose-finding studies of the mRNA vaccine BNT162b2 (Pfizer-BioNTech) suggest that a fractional dose induces comparable antibody responses to the full dose in people <55 years. Here, we report the safety and immunogenicity of a fractional dose regimen of the BNT162b2 vaccine.

Humoral and cellular immune correlates of protection against COVID-19 in kidney transplant recipients.

As solid organ transplant recipients are at high risk of severe COVID-19 and respond poorly to primary SARS-CoV-2 mRNA vaccination, they have been prioritized for booster vaccination. However, an immunological correlate of protection has not been identified in this vulnerable population. We conducted a prospective monocentric cohort study of 65 kidney transplant recipients who received 3 doses of BNT162b2 mRNA vaccine.

A Genome-Wide CRISPR Interference Screen Reveals an StkP-Mediated Connection between Cell Wall Integrity and Competence in Streptococcus salivarius.

Competence is one of the most efficient bacterial evolutionary and adaptative strategies by synchronizing production of antibacterial compounds and integration of DNA released by dead cells. In most streptococci, this tactic is orchestrated by the ComRS system, a pheromone communication device providing a short time window of activation in which only part of the population is responsive. Understanding how this developmental process integrates multiple inputs to fine-tune the adequate response is a long-standing question.

Competence shut-off by intracellular pheromone degradation in salivarius streptococci.

Competence for DNA transformation is a major strategy for bacterial adaptation and survival. Yet, this successful tactic is energy-consuming, shifts dramatically the metabolism, and transitory impairs the regular cell-cycle. In streptococci, complex regulatory pathways control competence deactivation to narrow its development to a sharp window of time, a process known as competence shut-off.