Immune response and severity of Omicron BA.5 reinfection among individuals previously infected with different SARS-CoV-2 variants.

Introduction: COVID-19 continues to spread worldwide, with an increasing number of individuals experiencing reinfection after recovering from their primary infection. However, the nature and progression of this infection remain poorly understood. We aimed to investigate the immune response, severity and outcomes of Omicron BA.5 reinfection among individuals previously infected with different SARS-CoV-2 variants. Methods: We enrolled 432 COVID-19 cases who had experienced prior infection with the ancestral SARS-CoV-2 virus, Delta variant or Omicron BA.2 variant between January 2020 and May 2022 in Guangzhou, China. All cases underwent follow-up from March to April, 2023 through telephone questionnaires and clinical visits. Nasal lavage fluid and peripheral blood were collected to assess anti-RBD IgA, anti-RBD IgG and virus-specific IFN-γ secreting T cells. Results: Our study shows that 73.1%, 56.7% and 12.5% of individuals with a prior infection of the ancestral virus, Delta or Omicron BA.2 variant experienced reinfection with the BA.5 variant, respectively. Fever, cough and sore throat were the most common symptoms of BA.5 reinfection, with most improving within one week and none progressing to a critical condition. Compared with individuals without reinfection, reinfected patients with a prior Delta infection exhibited elevated levels of nasal anti-RBD IgA, serum anti-RBD IgG and IFN-γ secreting T cells, whereas there was no noticeable change in reinfected individuals with a prior BA.2 infection. Conclusion: These results suggest that BA.5 reinfection is common but severe outcomes are relatively rare. Reinfection with a novel SARS-CoV-2 variant different from the prior infection may induce a more robust immune protection, which should be taken into account during vaccine development.

Factors associated with diagnostic accuracy, technical success and adverse events of endoscopic ultrasound-guided fine-needle biopsy: A systematic review and meta-analysis.

BACKGROUND AND AIM: Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is used to diagnose lesions within or adjacent to the digestive tract. However, there is no report on the overall diagnostic accuracy, technical success, and adverse events of FNB. The aims of this study were to conduct a systematic review and meta-analysis to comprehensively assess the diagnostic accuracy, technical success, and adverse events of FNB. METHODS: Pubmed, Embase, and Cochrane Library databases were searched for relevant articles published in English from January 1998 to May 2019 (No. CRD42019141647). Primary outcomes were EUS-FNB related diagnostic accuracy rate, technical success rate, and adverse event rate. RESULTS: A total of 51 articles including 5330 patients met our criteria. The overall EUS-FNB related diagnostic accuracy rate, technical success rate, and adverse event rate was 90.82% [95% confidence interval (CI) 88.69-92.76%], 99.71% [95% CI 99.35-99.93%], and 0.59% [95% CI 0.29-1.0%], respectively. Biopsy with 22G needle could increase the diagnostic accuracy rate and technical success rate to 92.17% [95% CI 89.32-94.61%] and 99.88% [95% CI 99.64-99.99%], respectively, and decrease the adverse event to 0.37% [95% CI 0.08-0.87%]. Moreover, it showed that 22G needle was an independent factor associated with a higher diagnostic accuracy rate and technical success rate and a lower adverse event rate (P = 0.04, P < 0.001, and P = 0.04, respectively) by univariate and multivariate meta-regression analyses. CONCLUSION: Endoscopic ultrasound-guided fine-needle biopsy is a feasible and safe procedure for lesions within or adjacent to the digestive tract. Biopsy using 22G needle could increase the diagnostic accuracy rate and technical success rate and decrease adverse event rate during the FNB procedure.