Clinical efficacy of the fourth dose of the BNT162b2 vaccine in maintenance dialysis patients.

BACKGROUND AND OBJECTIVES: Highly effective vaccines against severe acute respiratory syndrome virus 2 have been developed and administered worldwide. However, protection from coronavirus disease 2019 is not absolute and an optimal vaccination regimen needs to be established. This study assessed the clinical efficacy of the coronavirus disease 2019 vaccine among dialysis patients receiving 3 or 4 doses of vaccine. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: This retrospective study was conducted using the electronic database of Clalit Health Maintenance Organization in Israel. Chronic dialysis patients treated with either hemodialysis or peritoneal dialysis during the coronavirus disease 2019 pandemic were included. We compared clinical outcomes of patients who had received three or four doses of the severe acute respiratory syndrome virus 2 vaccine. RESULTS: This study included 1,030 patients on chronic dialysis, with a mean age of 68 ± 13 years. Among them, 502 patients had received 3 doses of the vaccine and 528 received 4 doses. Severe acute respiratory syndrome virus 2 infection rates, severe COVID-19 that resulted in hospitalizations, COVID-19-related mortality and all-cause mortality rates were lower among chronic dialysis patients who received a fourth dose of vaccine as compared to those who received only 3 doses (after controlling for age, sex and comorbidities). Despite lower mortality rates observed with the Omicron variant, the fourth dose was significantly associated with reduced COVID-19-related mortality (1.7% vs. 3.8%, p = 0.04). Odds ratio for COVID-19-related mortality was 0.44 with 95% CI 0.2-0.98. CONCLUSIONS: As seen in the general population and with previous vaccine boosters, the fourth dose of the BNT162b2 vaccine reduced rates of severe COVID-19-related hospitalization and mortality among chronic dialysis patients. Further studies are needed to establish the optimal regimens of vaccination for patients on chronic dialysis.

The effects of obesity and metabolic abnormalities on severe COVID-19-related outcomes after vaccination: A population-based study.

Breakthrough SARS-CoV-2 infections of vaccinated individuals are being reported globally, resulting in an increased risk of hospitalization and death among such patients. Therefore, it is crucial to identify the modifiable risk factors that may affect the protective efficacy of vaccine use against the development of severe COVID-19 and thus to initiate early medical interventions. Here, in population-based studies using the UK Biobank database and the 2021 National Health Interview Survey (NHIS), we analyzed 20,362 participants aged 50 years or older and 2,588 aged 18 years or older from both databases who tested positive for SARS-COV-2, of whom 33.1% and 67.7% received one or more doses of vaccine, respectively. In the UK Biobank, participants are followed from the vaccination date until October 18, 2021. We found that obesity and metabolic abnormalities (namely, hyperglycemia, hyperlipidemia, and hypertension) were modifiable factors for severe COVID-19 in vaccinated patients (all p < 0.05). When metabolic abnormalities were present, regardless of obesity, the risk of severe COVID-19 was higher than that of metabolically normal individuals (all p < 0.05). Moreover, pharmacological interventions targeting such abnormalities (namely, antihypertensive [adjusted hazard ratio (aHR) 0.64, 95% CI 0.48-0.86; p = 0.003], glucose-lowering [aHR 0.55, 95% CI 0.36-0.83; p = 0.004], and lipid-lowering treatments [aHR 0.50, 95% CI 0.37-0.68; p < 0.001]) were significantly associated with a reduced risk for this outcome. These results show that more proactive health management of patients with obesity and metabolic abnormalities is critical to reduce the incidence of severe COVID-19 after vaccination.