Coronavirus disease 2019 (COVID‐19), the highly contagious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has spread worldwide with millions of cases and more than 5 million deaths to date. SARS‐CoV‐2 has caused serious damage all over the world with many countries experiencing the third or the fourth wave of the viral disease outbreaks, mainly due to the emergence of mutant variants. Those who unvaccinated remain most vulnerable to COVID‐19 and its variants. COVID‐19 vaccination, along with prevention strategies, is a critical measure to defense against the disease. COVID‐19 vaccination can reduce the spread of virus and help protect susceptible population. Although herd immunity might not be realized solely by vaccination, COVID‐19 vaccines have been proved to be effective in reducing the risk of severe disease, hospitalization, and even death. It is recommended that people get vaccinated as soon as they are eligible. This review summarizes the recent SARS‐CoV‐2 variants that brought challenges for vaccination and herd immunity and discusses promising management strategies.

Introduction: Pulmonary infections are frequent in immunocompromised hosts (ICH), and microbial detection is difficult. As a new method, nextgeneration sequencing (NGS) may offer a solution.Objectives: This study aimed to assess the impact of NGS-assisted pathogenic detection on the diagnosis, treatment, and outcomes of ICH complicated by pulmonary infection and radiographic evidence of bilateral diffuse lesions.Methods: This study enrolled 356 patients with ICH complicated by pulmonary infection that were admitted to Zhongshan Hospital, Fudan University, from November 17, 2017, to November 23, 2018, including 102 and 254 in the NGS and non-NGS groups, respectively. Clinical characteristics, detection time, rough positive rate, effective positive rate, impact on anti-infective treatment plan, 30-day/60-day mortality, and in-hospital mortality were compared. Results: NGS-assisted pathogenic detection reduced detection time (28.2 h [interquartile range (IQR) 25.9-29.83 h] vs. 50.50 h [IQR 47.90-90.91 h], P < 0.001), increased positive rate, rate of mixed infection detected, effective positive rate, and proportion of antibiotic treatment modification (45.28% vs. 89.22%, 4.72% vs. 51.96%, 21.65% vs. 64.71%, 16.54% vs. 46.08%, P < 0.001). The NGS group had a significantly lower 60-day mortality rate (18.63% Donghui Zhang, Shujing Chen and Ying Wang contributed equally to this work.