The current study systematically reviewed, summarized and meta-analyzed the clinical features of the vaccines in clinical trials to provide a better estimate of their efficacy, side effects and immunogenicity. All relevant publications were systematically searched and collected from major databases up to 12 March 2021. A total of 25 RCTs (123 datasets), 58,889 cases that received the COVID-19 vaccine and 46,638 controls who received placebo were included in the meta-analysis. In total, mRNA-based and adenovirus-vectored COVID-19 vaccines had 94.6% (95% CI 0.936–0.954) and 80.2% (95% CI 0.56–0.93) efficacy in phase II/III RCTs, respectively. Efficacy of the adenovirus-vectored vaccine after the first (97.6%; 95% CI 0.939–0.997) and second (98.2%; 95% CI 0.980–0.984) doses was the highest against receptor-binding domain (RBD) antigen after 3 weeks of injections. The mRNA-based vaccines had the highest level of side effects reported except for diarrhea and arthralgia. Aluminum-adjuvanted vaccines had the lowest systemic and local side effects between vaccines’ adjuvant or without adjuvant, except for injection site redness. The adenovirus-vectored and mRNA-based vaccines for COVID-19 showed the highest efficacy after first and second doses, respectively. The mRNA-based vaccines had higher side effects. Remarkably few experienced extreme adverse effects and all stimulated robust immune responses.

Natural killer (NK) cells are among the most important innate immunity members, which are the first cells that fight against infected cells. The function of these cells is impaired in patients with...

Alveolar macrophages are pivotal components of the lung's innate immune defense against respiratory virus infections. Their multifaceted role spans from viral clearance to modulation of immune responses, making them essential players in shaping disease outcomes. In this comprehensive review collection, we look into the intricate interplay between Alveolar macrophages and various respiratory viruses, shedding light on their dynamic contributions to immune resilience. From influenza to respiratory syncytial virus, Alveolar macrophages emerge as sentinels of the airways, actively participating in viral detection and initiating rapid antiviral responses. Their ability to recognize viral pathogens triggers a cascade of events, including cytokine and chemokine production that guides the recruitment and activation of immune effectors. Furthermore, Alveolar macrophages impact the fate of adaptive immune responses by modulating the activation of T lymphocytes and the secretion of key cytokines. These reviews encompass a range of insights, including the regulation of inflammasome activation, the influence of Alveolar macrophages on cytokine dysregulation, and their role in preventing secondary bacterial pneumonia post-infection. Collectively, they highlight the significance of Alveolar macrophages in preserving pulmonary integrity and immune homeostasis during viral challenges.

Human metapneumovirus (hMPV) is a significant respiratory pathogen, yet its global prevalence and epidemiological patterns remain poorly characterized. This study presents the first comprehensive systematic review and meta-analysis of hMPV prevalence among patients with respiratory tract infections (RTIs), addressing a critical gap in the literature, and clarifying the association between hMPV infection and RTIs. We conducted a systematic search across PubMed, Scopus, and Web of Science, from 2002 to 2024. Studies reporting hMPV prevalence detected by Polymerase chain reaction-based methods in respiratory samples were included. Data was analyzed using random-effects models, with subgroup analyses by age, region, diagnostic methods, and patient’s demographic. The main outcome was hMPV prevalence among patients with RTIs. The global pooled prevalence of hMPV among 2,236,820 patients with RTIs was 5.3% (95% CI: 5.0%–5.6%). Prevalence was highest in children under 5 years (6.7%) and lowest in adults (2.5%). Lower respiratory infections showed the highest prevalence (8.2%), with bronchiolitis (7.0%) and pneumonia (5.5%) being prominent. Inpatients exhibited a significantly higher prevalence of hMPV (6.1%) compared to outpatients (3.3%). Among hMPV-positive samples, type A was more prevalent than type B. A meta-analysis of 41 case-control datasets revealed a significant association between hMPV infection and respiratory infections (pooled odds ratio [OR] = 4.6; 95% CI: 3.7–5.6; I² = 14.4%). This first-of-its-kind meta-analysis highlights hMPV as a major contributor to RTIs, particularly in young children and severe respiratory conditions. The findings show the need for improved diagnostic strategies, targeted surveillance, and vaccine development to mitigate hMPV’s global burden. This study was financially supported by the 10.13039/100012021 Iran University of Medical Sciences (Grant Number: 1402-2-75-25881).