Efficacy and safety of a fourth dose of the COVID-19 vaccine in kidney transplant recipients: A systematic review and meta-analysis.

BACKGROUND: Kidney transplant recipients (KTRs) who become infected with SARS-CoV-2 are at greater risk of serious illness and death than the general population. To date, the efficacy and safety of the fourth dose of the COVID-19 vaccine in KTRs have not been systematically discussed. METHODS: This systematic review and meta-analysis included articles from PubMed, Embase, the Cochrane Library, Web of Science, China National Knowledge Infrastructure, and Wanfang Med Online published before May 15, 2022. Studies evaluating the efficacy and safety of a fourth dose of the COVID-19 vaccine in kidney transplant recipients were selected. RESULTS: Nine studies were included in the meta-analysis, with a total of 727 KTRs. The overall pooled seropositivity rate after the fourth COVID-19 vaccine was 60% (95% CI, 49%-71%, I2 = 87.83%, p > 0.01). The pooled proportion of KTRs seronegative after the third dose that transitioned to seropositivity after the fourth dose was 30% (95% CI, 15%-48%, I2 = 94.98%, p < 0.01). CONCLUSIONS: The fourth dose of the COVID-19 vaccine was well tolerated in KTRs with no serious adverse effects. Some KTRs showed a reduced response even after receiving the fourth vaccine dose. Overall, the fourth vaccine dose effectively improved seropositivity in KTRs, as recommended by the World Health Organization for the general population.

Hydroxypropyl methylcellulose 2% for dry eye prevention during phacoemulsification in senile and diabetic patients.

PURPOSE: To assess the effect of hydroxypropyl methylcellulose (HPMC) 2% to prevent dry eye during phacoemulsification in senile and diabetic patients. METHODS: This prospective interventional case series comprised 60 eyes (44 patients) with age-related cataract scheduled for standardized phacoemulsification surgery. The patients were assigned to receive either balanced saline solution (BSS, 30 eyes) or HPMC 2% (30 eyes) during surgery. Preoperative and postoperative examinations (1, 3, 7 and 30 days) included measurements of automatic noninvasive tear film breakup time (NITBUT), fluorescein staining, Schirmer I test, tear meniscus height, depth and area and subjective symptoms. Intraoperative application frequency was also assessed. RESULTS: The mean age of patients was 68.7 ± 2.3 years. The application frequency of BSS during surgery was significantly reduced in HPMC group (P = 0.001). The incidence of dry eye syndrome (DES) was significantly reduced in HPMC group in both senile and diabetic patients. Scores of subjective symptoms were significantly higher in the BSS group in 1 day (P = 0.003) and 3 days (P = 0.043) postoperatively. The first and average NITBUT were significantly higher in HPMC group in 1 day and 3 days after surgery, respectively (P = 0.012 and P = 0.024, respectively). NITBUT values did not significantly change postoperatively in the HPMC group (P > 0.05), while they were significantly lower postoperatively in the BSS group. CONCLUSIONS: Application of HPMC 2% during phacoemulsification reduced the incidence of DES and improved patients' satisfaction in both senile and diabetic cataract patients. It was also effective in maintaining corneal hydration and was able to significantly reduce the application frequency intraoperatively.