25-Hydroxyvitamin D concentrations do not affect the humoral or cellular immune response following SARS-CoV-2 mRNA vaccinations.

BACKGROUND: To improve effectiveness of vaccination against SARS-CoV-2, it is important to identify factors that influence the immune response induced by vaccination. Evidence for the role of vitamin D in immune response against SARS-CoV-2 is contradictory. It is therefore of interest whether 25-hydroxyvitamin D (25[OH]D) concentrations affect the humoral and/or cellular response following SARS-CoV-2 vaccination. METHODS: In this prospective cohort study, blood samples were collected from 98 SARS-CoV-2 naive health care workers (HCW) receiving the first two doses of either BNT162b2 or mRNA-1273 in 2021. Wild-type spike (S) protein binding and neutralizing antibodies were determined approximately three weeks after the first dose and four to five weeks after the second dose. Antigen specific T-cells and functionality (proliferative response and interferon gamma [IFN-γ] release) were determined in 18 participants four weeks after the second dose of BNT162b2. We studied the association between 25(OH)D concentrations, which were determined prior to vaccination, and humoral and cellular immune responses following vaccination. RESULTS: We found no association between 25(OH)D concentrations (median 55.9 nmol/L [IQR 40.5-69.8]) and binding or neutralizing antibody titers after complete vaccination (fold change of antibody titers per 10 nmol/L 25(OH)D increase: 0.98 [95% CI 0.93-1.04] and 1.03 [95% CI: 0.96-1.11], respectively), adjusted for age, sex and type of mRNA vaccine. Subsequently, continuous 25(OH)D concentrations were divided into commonly used clinical categories (<25 nmol/L [n = 6, 6%], 25-49 nmol/L [n = 33, 34%], 50-75 nmol/L [n = 37, 38%] and ≥75 nmol/L [n = 22, 22%]), but no association with the humoral immune response following vaccination was found. Also, 25(OH)D concentrations were not associated with the SARS-CoV-2 specific T cell response. CONCLUSION: No association was found between 25(OH)D concentrations and the humoral or cellular immune response following mRNA vaccination against SARS-CoV-2. Based on our findings there is no rationale to advise vitamin D optimization preceding SARS-CoV-2 vaccination in HCW with moderate vitamin D status.

Risk of SARS-CoV-2 transmission upon return to work in RNA-positive healthcare workers.

BACKGROUND: Healthcare workers (HCWs) are at risk for coronavirus disease 2019 (COVID-19), and for spreading severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) amongst colleagues and patients. AIM: To study the presence of SARS-CoV-2 RNA and possible onward transmission by HCWs upon return to work after COVID-19, and association with disease severity and development of antibodies over time. METHODS: Unvaccinated HCWs with positive SARS-CoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) were recruited prospectively. Data on symptoms were collected via telephone questionnaires on days 2, 7, 14 and 21 after a positive test. Upon return to work, repeat SARS-CoV-2 RT-PCR was performed and serum was collected. Repeat serum samples were collected at weeks 4, 8, 12 and 16 to determine antibody dynamics over time. Phylogenetic analysis was conducted to investigate possible transmission events originating from HCWs with a positive repeat RT-PCR. FINDINGS: Sixty-one (84.7%) participants with mild/moderate COVID-19 had a repeat SARS-CoV-2 RT-PCR performed upon return to work (median 13 days after symptom onset), of which 30 (49.1%) were positive with a median cycle threshold (Ct) value of 29.2 (IQR 26.9-29.9). All HCWs developed antibodies against SARS-CoV-2. No significant differences in symptomatology and presence of antibodies were found between repeat RT-PCR-positive and -negative HCWs. Eleven direct colleagues of six participants with a repeat RT-PCR Ct value <30 tested positive after the HCW returned to work. Phylogenetic and epidemiologic analysis did not indicate onward transmission through HCWs who were SARS-CoV-2 RNA positive upon return to work. CONCLUSIONS: HCWs regularly return to work with substantial SARS-CoV-2 RNA loads. However, this study found no evidence for subsequent in-hospital transmission.

The impact of laboratory closing times on delay of adequate therapy in blood stream infections.

BACKGROUND: Patients with bloodstream infections need early adequate antimicrobial treatment to reduce mortality. This raises the question of timing and logistics. How important is the time of day when a culture is flagged positive to the processing of blood cultures and optimisation of antimicrobial therapy? METHODS: We performed a retrospective study assessing the time delay of a positive blood culture result during and after office hours and its impact on adequate antimicrobial therapy. Process duration from the moment of culture positivity to Gram stain completion was compared at different timepoints during the day in a medium-sized hospital with an offsite microbiological laboratory. RESULTS: Ninety-four patients with positive, noncontaminated blood cultures were included. Sixty-six patients (70%) received adequate empirical therapy; this increased to 76 cases (82%) and to 88 cases (95%) after analysis of Gram stain results and complete determination, respectively (p < 0.05 for all comparisons). Median duration from culture positivity to Gram stain completion (including offsite culture transport) increased from a median of four to 12 hours if time of cultures turned positive after office hours (p < 0.05), irrespective of the adequacy of empirical coverage. This also resulted in a median 12-hour delay for the complete process from time of culture positivity to administration of the antimicrobial drug (p < 0.05). CONCLUSION: Processing blood cultures after office hours is often deferred, which can lead to a delay in adequate antimicrobial therapy for patients with bloodstream infections.

[Orphanet: a European database for rare diseases]. / Orphanet: een Europese database over zeldzame ziekten.

Orphanet is a European initiative that aims to improve the management and treatment of rare diseases. It comprises a database dedicated to information on rare diseases and orphan drugs, and offers services adapted to the needs of patients and their families, health professionals, and researchers. The database can be accessed through the website (www.orpha.net) and has some interesting options for searching, for example research projects, support groups or searching by clinical signs. Health professionals are encouraged to add activities concerning rare diseases to the database.