Prognostic performance of blood neurofilament light chain protein in hospitalized COVID-19 patients without major central nervous system manifestations: an individual participant data meta-analysis.

BACKGROUND AND AIMS: To investigate the prognostic value of blood neurofilament light chain protein (NfL) levels in the acute phase of coronavirus disease 2019 (COVID-19). METHODS: We conducted an individual participant data (IPD) meta-analysis after screening on MEDLINE and Scopus to May 23rd 2022. We included studies with hospitalized adult COVID-19 patients without major COVID-19-associated central nervous system (CNS) manifestations and with a measurement of blood NfL in the acute phase as well as data regarding at least one clinical outcome including intensive care unit (ICU) admission, need of mechanical ventilation (MV) and death. We derived the age-adjusted measures NfL Z scores and conducted mixed-effects modelling to test associations between NfL Z scores and other variables, encompassing clinical outcomes. Summary receiver operating characteristic curves (SROCs) were used to calculate the area under the curve (AUC) for blood NfL. RESULTS: We identified 382 records, of which 7 studies were included with a total of 669 hospitalized COVID-19 cases (mean age 66.2 ± 15.0 years, 68.1% males). Median NfL Z score at admission was elevated compared to the age-corrected reference population (2.37, IQR: 1.13-3.06, referring to 99th percentile in healthy controls). NfL Z scores were significantly associated with disease duration and severity. Higher NfL Z scores were associated with a higher likelihood of ICU admission, need of MV, and death. SROCs revealed AUCs of 0.74, 0.80 and 0.71 for mortality, need of MV and ICU admission, respectively. CONCLUSIONS: Blood NfL levels were elevated in the acute phase of COVID-19 patients without major CNS manifestations and associated with clinical severity and poor outcome. The marker might ameliorate the performance of prognostic multivariable algorithms in COVID-19.

Smartphone-based active vaccine safety surveillance (SmartVax) at a Swiss adult vaccination clinic - a pilot study.

INTRODUCTION: Post-licensure surveillance of adverse events following immunisation (AEFI) is critical for detecting rare but severe AEFI. SmartVax software, using smartphone technology, actively solicits reports of AEFI via automated, opt-out SMS surveys to vaccine recipients in the days following immunisation. We report on a pilot study to test the feasibility and acceptance of SmartVax in Switzerland. METHODS: Between February and September 2020, consecutive subjects immunised at an adult immunisation clinic and the employee health service at the University Hospital of Basel were screened. Participants included three subgroups: healthcare workers (HCW), subjects with immune-mediated inflammatory diseases (IMID) and clients of the regular adult immunisation clinic. Three days after vaccination, participants received an SMS inquiring if they had any AEFI. In the case of an AEFI, subjects received an automated SMS with a link to an online survey assessing the type and temporal evolution of the AEFI. Descriptive statistics of response rate, time-to-response, frequency and type of AEFI by vaccine and clinical subgroup were performed. RESULTS: Of 293 subjects screened, 276 were included (46.6% routine vaccination check-up visits, 33.3% HCW, 20.1% IMID patients) receiving 625 vaccinations during 360 immunisation visits. The SMS response rate was high (90.3%), with a median time-to-respond of 47 minutes (interquartile range11-205). After 29.8% of immunisation visits at least one AEFI was reported. There were no differences in frequency or type of AEFI between the three clinical subgroups. The recombinant, adjuvanted zoster vaccine Shingrix® was associated with the highest rate of local and systemic reactions. CONCLUSION: Monitoring post-licensure vaccine safety using the active SMS-based surveillance system SmartVax is feasible in Switzerland. We observed a high acceptance in the diverse study population, including healthcare workers and IMID patients. High response rates in the elderly and reliable monitoring almost in real-time make SmartVax a promising tool for COVID-19 vaccine safety monitoring.