Associations of psychological wellbeing with COVID-19 hospitalization and mortality in adults aged 50 years or older from 25 European countries and Israel.

Background: Lower psychological wellbeing is associated with poor outcomes in a variety of diseases and healthy populations. However, no study has investigated whether psychological wellbeing is associated with the outcomes of COVID-19. This study aimed to determine whether individuals with lower psychological wellbeing are more at risk for poor outcomes of COVID-19. Methods: Data were from the Survey of Health, Aging, and Retirement in Europe (SHARE) in 2017 and SHARE's two COVID-19 surveys in June-September 2020 and June-August 2021. Psychological wellbeing was measured using the CASP-12 scale in 2017. The associations of the CASP-12 score with COVID-19 hospitalization and mortality were assessed using logistic models adjusted for age, sex, body mass index, smoking, physical activity, household income, education level, and chronic conditions. Sensitivity analyses were performed by imputing missing data or excluding cases whose diagnosis of COVID-19 was solely based on symptoms. A confirmatory analysis was conducted using data from the English Longitudinal Study of Aging (ELSA). Data analysis took place in October 2022. Results: In total, 3,886 individuals of 50 years of age or older with COVID-19 were included from 25 European countries and Israel, with 580 hospitalized (14.9%) and 100 deaths (2.6%). Compared with individuals in tertile 3 (highest) of the CASP-12 score, the adjusted odds ratios (ORs) of COVID-19 hospitalization were 1.81 (95% CI, 1.41-2.31) for those in tertile 1 (lowest) and 1.37 (95% CI, 1.07-1.75) for those in tertile 2. As for COVID-19 mortality, the adjusted ORs were 2.05 (95% CI, 1.12-3.77) for tertile 1 and 1.78 (95% CI, 0.98-3.23) for tertile 2, compared with tertile 3. The results were relatively robust to missing data or the exclusion of cases solely based on symptoms. This inverse association of the CASP-12 score with COVID-19 hospitalization risk was also observed in ELSA. Conclusion: This study shows that lower psychological wellbeing is independently associated with increased risks of COVID-19 hospitalization and mortality in European adults aged 50 years or older. Further study is needed to validate these associations in recent and future waves of the COVID-19 pandemic and other populations.

HIV-related mortality in the United States during the COVID-19 pandemic: A population-based study.

BACKGROUND: US progress toward ending the HIV epidemic was disrupted during the COVID-19 pandemic. OBJECTIVES: To determine the impact of the pandemic on HIV-related mortality and potential disparities. METHODS: Using data from the Centers for Disease Control and Prevention and the United States (US) Census Bureau, HIV-related mortality data of decedents aged ≥25 years between 2012 and 2021 were analyzed. Excess HIV-related mortality rates were estimated by determining the difference between observed and projected mortality rates during the pandemic. The trends of mortality were quantified with joinpoint regression analysis. RESULTS: Of the 79,725 deaths documented in adults aged 25 years and older between 2012 and 2021, a significant downward trend was noted in HIV-related mortality rates before the pandemic, followed by a surge during the pandemic. The observed mortality rates were 18.8% (95% confidence interval [CI]: 13.1%-25.5%) and 25.4% (95%CI: 19.9%-30.4%) higher than the projected values in 2020 and 2021, respectively. Both of these percentages were higher than that in the general population in 2020 (16.4%, 95%CI: 14.9%-17.9%) and 2021 (19.8%, 95%CI: 18.0%-21.6%), respectively. Increased HIV-related mortality was observed across all age subgroups, but those aged 25-44 years demonstrated the greatest relative increase and the lowest COVID-19-related deaths when compared to middle- and old-aged decedents. Disparities were observed across racial/ethnic subgroups and geographic regions. CONCLUSIONS: The pandemic led to a reversal in the attainments made to reduce the prevalence of HIV. Individuals living with HIV were disproportionately affected during the pandemic. Thoughtful policies are needed to address the disparity in excess HIV-related mortality.

Trends of Cirrhosis-related Mortality in the USA during the COVID-19 Pandemic.

Immunocompromised status and interrupted routine care may render patients with cirrhosis vulnerable to the coronavirus disease 2019 (COVID-19) pandemic. A nationwide dataset that includes more than 99% of the decedents in the U.S. between April 2012 and September 2021 was used. Projected age-standardized mortality during the pandemic were estimated according to prepandemic mortality rates, stratified by season. Excess deaths were determined by estimating the difference between observed and projected mortality rates. A temporal trend analysis of observed mortality rates was also performed in 0.83 million decedents with cirrhosis between April 2012 and September 2021 was included. Following an increasing trend of cirrhosis-related mortality before the pandemic, with a semiannual percentage change (SAPC) of 0.54% [95% confidence interval (CI): (0.0-1.0%), p=0.036], a precipitous increase with seasonal variation occurred during the pandemic (SAPC 5.35, 95% CI: 1.9-8.9, p=0.005). Significantly increased mortality rates were observed in those with alcohol-associated liver disease (ALD), with a SAPC of 8.44 (95% CI: 4.3-12.8, p=0.001) during the pandemic. All-cause mortality of nonalcoholic fatty liver disease rose steadily across the entire study period with a SAPC of 6.79 (95% CI: 6.3-7.3, p<0.001). The decreasing trend of HCV-related mortality was reversed during the pandemic, while there was no significant change in HBV-related deaths. While there was significant increase in COVID-19-related deaths, more than 55% of the excess deaths were the indirect impact of the pandemic. We observed an alarming increase in cirrhosis-related deaths during the pandemic especially for ALD, with evidence in both direct and indirect impact. Our findings have implications on formulating policies for patients with cirrhosis.

Isothermal nucleic acid amplification technology for rapid detection of virus.

While the research field and industrial market of in vitro diagnosis (IVD) thrived during and post the COVID-19 pandemic, the development of isothermal nucleic acid amplification test (INAAT) based rapid diagnosis was engendered in a global wised large measure as a problem-solving exercise. This review systematically analyzed the recent advances of INAAT strategies with practical case for the real-world scenario virus detection applications. With the qualities that make INAAT systems useful for making diagnosis relevant decisions, the key performance indicators and the cost-effectiveness of enzyme-assisted methods and enzyme-free methods were compared. The modularity of nucleic acid amplification reactions that can lead to thresholding signal amplifications using INAAT reagents and their methodology design were examined, alongside the potential application with rapid test platform/device integration. Given that clinical practitioners are, by and large, unaware of many the isothermal nucleic acid test advances. This review could bridge the arcane research field of different INAAT systems and signal output modalities with end-users in clinic when choosing suitable test kits and/or methods for rapid virus detection.

Excess risk for acute myocardial infarction mortality during the COVID-19 pandemic.

The COVID-19 pandemic has had a detrimental impact on the healthcare system. Our study armed to assess the extent and the disparity in excess acute myocardial infarction (AMI)-associated mortality during the pandemic, through the recent Omicron outbreak. Using data from the CDC's National Vital Statistics System, we identified 1 522 669 AMI-associated deaths occurring between 4/1/2012 and 3/31/2022. Accounting for seasonality, we compared age-standardized mortality rate (ASMR) for AMI-associated deaths between prepandemic and pandemic periods, including observed versus predicted ASMR, and examined temporal trends by demographic groups and region. Before the pandemic, AMI-associated mortality rates decreased across all subgroups. These trends reversed during the pandemic, with significant rises seen for the youngest-aged females and males even through the most recent period of the Omicron surge (10/2021-3/2022). The SAPC in the youngest and middle-age group in AMI-associated mortality increased by 5.3% (95% confidence interval [CI]: 1.6%-9.1%) and 3.4% (95% CI: 0.1%-6.8%), respectively. The excess death, defined as the difference between the observed and the predicted mortality rates, was most pronounced for the youngest (25-44 years) aged decedents, ranging from 23% to 34% for the youngest compared to 13%-18% for the oldest age groups. The trend of mortality suggests that age and sex disparities have persisted even through the recent Omicron surge, with excess AMI-associated mortality being most pronounced in younger-aged adults.

Impact of the COVID-19 pandemic on liver disease-related mortality rates in the United States.

BACKGROUND: The pandemic has resulted in an increase of deaths not directly related to COVID-19 infection. We aimed to use a national death dataset to determine the impact of the pandemic on people with liver disease in the U.S, focusing on alcohol-associated liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). METHODS: Using data from the National Vital Statistic System from the CDC WONDER platform and ICD-10 codes, we identified deaths associated with liver disease. We evaluated observed versus predicted mortality for 2020-2021 based on trends from 2010-2019 with joinpoint and prediction modeling analysis. RESULTS: Among 626,090 chronic liver disease-related deaths between 2010 and 2021, Age-standardized mortality rates (ASMR) for ALD dramatically increased between 2010-2019 and 2020-2021 (annual percentage change [APC] 3.5% to 17.6%, P<0.01), leading to a higher observed ASMR (per 100,000 persons) than predicted for 2020 (15.67 vs.13.04) and 2021 (17.42 vs.13.41). ASMR for NAFLD also increased during the pandemic (APC:14.5%), while the rates for hepatitis B and C decreased. Notably, the ASMR rise for ALD was most pronounced in non-Hispanic Whites, Blacks, and Alaska Indians/Native Americans (APC: 11.7%, 10.8%, 18.0%, all P<0.05), with similar but less critical findings for NAFLD while rates were steady for non-Hispanic Asians throughout 2010-2021 (APC: 4.9%). The ASMR rise for ALD was particularly severe for the 25-44 age group (APC: 34.6%, versus 13.7% and 12.6% for 45-64 and ≥65, all P<0.01), which were also all higher than pre-COVID-19 rates (all P<0.01). CONCLUSIONS: ASMR for ALD and NAFLD increased at an alarming rate during the COVID-19 pandemic with the largest disparities among the young, non-Hispanic White, and Alaska Indian/Native American populations. LAY SUMMARY: The impact of the pandemic on people with liver disease in the U.S remains unclear. This study indicated that age-standardized mortality rates for alcohol associated liver disease and non-alcohol fatty liver disease greatly accelerated during the COVID-19 pandemic with the largest disparities among the young, non-Hispanic White, and Alaska Indian/Native American populations. Increasing awareness about the care importance of chronic liver disease in specific populations must be prioritized.

Racial and Ethnic Disparities in Years of Potential Life Loss Among Patients With Cirrhosis During the COVID-19 Pandemic in the United States.

INTRODUCTION: Our aim was to evaluate the impact of race/ethnicity on cirrhosis-related premature death during the COVID-19 pandemic. METHODS: We obtained cirrhosis-related death data (n = 872,965, January 1, 2012-December 31, 2021) from the US National Vital Statistic System to calculate age-standardized mortality rates and years of potential life lost (YPLL) for premature death aged 25-64 years. RESULTS: Significant racial/ethnic disparity in cirrhosis-related age-standardized mortality rates was noted prepandemic but widened during the pandemic, with the highest excess YPLL for the non-Hispanic American Indian/American Native (2020: 41.0%; 2021: 68.8%) followed by other minority groups (28.7%-45.1%), and the non-Hispanic White the lowest (2020: 20.7%; 2021: 31.6%). COVID-19 constituted >30% of the excess YPLLs for Hispanic and non-Hispanic American Indian/American Native in 2020, compared with 11.1% for non-Hispanic White. DISCUSSION: Ethnic minorities with cirrhosis experienced a disproportionate excess death and YPLLs in 2020-2021.

Excess Non-COVID Mortality Among IBD Decedents During the COVID-19 Pandemic

Methods: This serial population-based analysis included data from the CDC’s National Vital Statistics System on IBD decedents aged ≥25 years from 1/1/06 to 12/31/21. The rise in neoplasm-related non-COVID deaths and mortality rates prior to hospital arrival during the pandemic suggests that indirect effects of the pandemic, such as delayed presentation, likely exacerbated healthcare disparities and adversely impacted timely interventions and care. Subgroup Analyses of Observed COVID, Non-COVID, and Predicted Age-Standardized Mortality Rates Among IBD Decedents Stratification Group Year COVID ASMRs Non-COVID ASMRs Predicted ASMRs with 95% CI Age UC 25-64 years 2020 0.01 0.20* 0.17 [0.15-0.19] 2021 0.03 0.18 0.17 [0.15-0.19] ≥65 years 2020 0.28 2.31 2.30 [2.01-2.58] 2021 0.28 2.53 2.45 [2.04-2.86] CD 25-64 years 2020 0.02 0.46 0.42 [0.37-0.47] 2021 0.04 0.46 0.45 [0.38-0.52] ≥65 years 2020 0.25 2.95 2.79 [2.46-3.12] 2021 0.33 3.15 2.87 [2.49-3.25] Sex UC Male 2020 0.07 0.70 0.68 [0.62-0.75] 2021 0.09 0.69 0.70 [0.63-0.78] Females 2020 0.06 0.54 0.53 [0.44-0.61] 2021 0.07 0.60 0.57 [0.44-0.70] CD Males 2020 0.06 0.94 0.93 [0.83-1.04] 2021 0.11 0.99 1.01 [0.86-1.16] Females 2020 0.06 0.95 0.90 [0.78-1.02] 2021 0.09 0.99 0.94 [0.76-1.12] Race UC Hispanics 2020 0.04 0.26 0.23 [0.07-0.38] Non-Hispanic whites 2020 0.07 0.71 0.71 [0.63-0.78] Non-Hispanic blacks 2020 0.02 0.39 0.41 [0.29-0.52] CD Hispanics 2020 0.03 0.27 0.27 [0.08-0.47] Non-Hispanic whites 2020 0.07 1.15 1.12 [0.99-1.25] Non-Hispanic blacks 2020 0.06 0.75* 0.55 [0.41-0.70] * Signifies statistical significance ASMRs are per 100,000 persons.

Excess diabetes mellitus-related deaths during the COVID-19 pandemic in the United States.

Background: Diabetes mellitus (DM) is a critical risk factor for severe SARS-CoV-2 infection, and SARS-CoV-2 infection contributes to worsening glycemic control. The COVID-19 pandemic profoundly disrupted the delivery of care for patients with diabetes. We aimed to determine the trend of DM-related deaths during the pandemic. Methods: In this serial population-based study between January 1, 2006 and December 31, 2021, mortality data of decedents aged ≥25 years from the National Vital Statistics System dataset was analyzed. Decedents with DM as the underlying or contributing cause of death on the death certificate were defined as DM-related deaths. Excess deaths were estimated by comparing observed versus expected age-standardized mortality rates derived from mortality during 2006-2019 with linear and polynomial regression models. The trends of mortality were quantified with joinpoint regression analysis. Subgroup analyses were performed by age, sex, race/ethnicity, and state. Findings: Among 4·25 million DM-related deaths during 2006-2021, there was a significant surge of more than 30% in mortality during the pandemic, from 106·8 (per 100,000 persons) in 2019 to 144·1 in 2020 and 148·3 in 2021. Adults aged 25-44 years had the most pronounced rise in mortality. Widened racial/ethnic disparity was observed, with Hispanics demonstrating the highest excess deaths (67·5%; 95% CI 60·9-74·7%), almost three times that of non-Hispanic whites (23·9%; 95% CI 21·2-26·7%). Interpretation: The United States saw an increase in DM-related mortality during the pandemic. The disproportionate rise in young adults and the widened racial/ethnic disparity warrant urgent preventative interventions from diverse stakeholders. Funding: National Natural Science Foundation of China.

The Epidemiological, Clinical Features and Outcomes of Imported Chinese COVID-19 Patients Following Inactivated Vaccines Injection.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination had been demonstrated as an effective way to reduce the risk of coronavirus disease 2019 (COVID-19), and only a few vaccines suffered from SARS-CoV-2 infection. However, limited data concerning the clinical features of these vaccines infected with SARS-CoV-2 can be identified. Methods: We retrospectively collected and analyzed epidemiological and clinical characteristics data of the imported COVID-19 cases who received Chinese inactivated vaccines abroad. Data were extracted from electronic medical records from a designated hospital in the Shaanxi Province of China between March 22 and May 17, 2021. Results: Totally, 46 confirmed SARS-CoV-2 infection patients were enrolled. The mean age was 40.5 years (range 20-61), 41 (89.1%) are male. Eighteen (39.1%) patients were from Pakistan. Fourteen (30.4%) patients had at least one comorbidity. Forty (87.0%) and 6 cases were fully vaccinated and partly vaccinated. The time interval between vaccination and infection was 88 days (IQR, 33-123), 31 (67.4%) and 15 (32.6%) were asymptomatic and symptomatic cases, respectively. Fever (3/46, 6.5%) was the most common symptom; however, none had a body temperature higher than 38.0°C, and no severe case was observed. Notably, the rate of SARS-CoV-2 shedding discontinuation at 7 days after hospitalization in asymptomatic cases was higher than symptomatic one (93.5% vs 40%, P < 0.0001). Conclusion: Individuals who received Chinese inactivated vaccines abroad remain to have the probability of being infected with SARS-CoV-2, but all the vaccines infected with SARS-CoV-2 were asymptomatic or had mild symptoms with favorable clinical outcomes.

COVID-19 epidemic in New York City: development of an age group-specific mathematical model to predict the outcome of various vaccination strategies.

BACKGROUND: Since December 14, 2020, New York City (NYC) has started the first batch of COVID-19 vaccines. However, the shortage of vaccines is currently an inevitable problem. Therefore, optimizing the age-specific COVID-19 vaccination is an important issue that needs to be addressed as a priority. OBJECTIVE: Combined with the reported COVID-19 data in NYC, this study aimed to construct a mathematical model with five age groups to estimate the impact of age-specific vaccination on reducing the prevalence of COVID-19. METHODS: We proposed an age-structured mathematical model and estimated the unknown parameters based on the method of Markov Chain Monte Carlo (MCMC). We also calibrated our model by using three different types of reported COVID-19 data in NYC. Moreover, we evaluated the reduced cumulative number of deaths and new infections with different vaccine allocation strategies. RESULTS: Compared with the current vaccination strategy in NYC, if we gradually increased the vaccination coverage rate for only one age groups from March 1, 2021 such that the vaccination coverage rate would reach to 40% by June 1, 2021, then as of June 1, 2021, the cumulative deaths in the 75-100 age group would be reduced the most, about 72 fewer deaths per increased 100,000 vaccinated individuals, and the cumulative new infections in the 0-17 age group would be reduced the most, about 21,591 fewer new infections per increased 100,000 vaccinated individuals. If we gradually increased the vaccination coverage rate for two age groups from March 1, 2021 such that the vaccination coverage rate would reach to 40% by June 1, 2021, then as of June 1, 2021, the cumulative deaths in the 65-100 age group would be reduced the most, about 36 fewer deaths per increased 100,000 vaccinated individuals, and the cumulative new infections in the 0-44 age group would be reduced the most, about 17,515 fewer new infections per increased 100,000 vaccinated individuals. In addition, if we had an additional 100,000 doses of vaccine for 0-17 and 75-100 age groups as of June 1, 2021, then the allocation of 80% to the 0-17 age group and 20% to the 75-100 age group would reduce the maximum numbers of new infections and deaths simultaneously in NYC. CONCLUSIONS: The COVID-19 burden including deaths and new infections would decrease with increasing vaccination coverage rate. Priority vaccination to the elderly and adolescents would minimize both deaths and new infections.

The impact of COVID-19 on the cascade of care of HCV in the US and China.

BACKGROUND AND OBJECTIVES: The COVID-19 pandemic imperiled the global health system. We aimed to determine the impact of COVID-19 on the care continuum of HCV-infected patients. MATERIAL AND METHODS: Two hundred and fifty-six patients who were prescribed a course of DAA therapy at three tertiary medical centers in the US and China between January 1, 2019 to June 30, 2020 were included. We assessed the proportions of patients who completed DAA therapy and had HCV RNA testing during and after the end of therapy. We also assessed the impact of utilization of telemedicine. RESULTS: The proportion of patients undergoing HCV RNA testing during DAA treatment decreased from >81.7% before pandemic to 67.8% during the pandemic (P=0.006), with a more prominent decrease in the US. There were significant decreases in HCV RNA testing >12 (P<0.001) and >20 weeks (P<0.001) post-treatment during COVID-19 era. Compared to pre-COVID period, post-treatment clinic encounters during COVID-19 era decreased significantly in China (Xi'an: 13.6% to 7.4%; Nanjing: 16.7% to 12.5%) but increased in the US (12.5% to 16.7%), mainly due to the use of telemedicine. There was a 4-fold increase in utilization of telemedicine in the US. CONCLUSIONS: COVID-19 pandemic carried profound impact on care for HCV patients in both the US and China. HCV cure rate assessment decreased by half during COVID era but the proportion of patients finishing DAA therapy was not significantly affected. Increased utilization of telemedicine led to increased compliance with DAA therapy but did not encourage patients to have their laboratory assessment for HCV cure.

Dynamic changes in liver function parameters in patients with coronavirus disease 2019: a multicentre, retrospective study.

BACKGROUND: Liver injuries have been reported in patients with coronavirus disease 2019 (COVID-19). This study aimed to investigate the clinical role played by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: In this multicentre, retrospective study, the parameters of liver function tests in COVID-19 inpatients were compared between various time-points in reference to SARS-CoV-2 shedding, and 3 to 7 days before the first detection of viral shedding was regarded as the reference baseline. RESULTS: In total, 70 COVID-19 inpatients were enrolled. Twenty-two (31.4%) patients had a self-medication history after illness. At baseline, 10 (14.3%), 7 (10%), 9 (12.9%), 2 (2.9%), 15 (21.4%), and 4 (5.7%) patients already had abnormal alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), albumin, and total bilirubin (TBIL) values, respectively. ALT and AST abnormal rates and levels did not show any significant dynamic changes during the full period of viral shedding (all p > 0.05). The GGT abnormal rate (p = 0.008) and level (p = 0.033) significantly increased on day 10 of viral shedding. Meanwhile, no simultaneous significant increases in abnormal ALP rates and levels were observed. TBIL abnormal rates and levels significantly increased on days 1 and 5 of viral shedding (all p < 0.05). Albumin abnormal decrease rates increased, and levels decreased consistently from baseline to SARS-CoV-2 clearance day (all p < 0.05). Thirteen (18.6%) patients had chronic liver disease, two of whom died. The ALT and AST abnormal rates and levels did not increase in patients with chronic liver disease during SARS-CoV-2 shedding. CONCLUSIONS: SARS-CoV-2 does not directly lead to elevations in ALT and AST but may result in elevations in GGT and TBIL; albumin decreased extraordinarily even when SARS-CoV-2 shedding ended.

How to Reduce the Transmission Risk of COVID-19 More Effectively in New York City: An Age-Structured Model Study.

Background: In face of the continuing worldwide COVID-19 epidemic, how to reduce the transmission risk of COVID-19 more effectively is still a major public health challenge that needs to be addressed urgently. Objective: This study aimed to develop an age-structured compartment model to evaluate the impact of all diagnosed and all hospitalized on the epidemic trend of COVID-19, and explore innovative and effective releasing strategies for different age groups to prevent the second wave of COVID-19. Methods: Based on three types of COVID-19 data in New York City (NYC), we calibrated the model and estimated the unknown parameters using the Markov Chain Monte Carlo (MCMC) method. Results: Compared with the current practice in NYC, we estimated that if all infected people were diagnosed from March 26, April 5 to April 15, 2020, respectively, then the number of new infections on April 22 was reduced by 98.02, 93.88, and 74.08%. If all confirmed cases were hospitalized from March 26, April 5, and April 15, 2020, respectively, then as of June 7, 2020, the total number of deaths in NYC was reduced by 67.24, 63.43, and 51.79%. When only the 0-17 age group in NYC was released from June 8, if the contact rate in this age group remained below 61% of the pre-pandemic level, then a second wave of COVID-19 could be prevented in NYC. When both the 0-17 and 18-44 age groups in NYC were released from June 8, if the contact rates in these two age groups maintained below 36% of the pre-pandemic level, then a second wave of COVID-19 could be prevented in NYC. Conclusions: If all infected people were diagnosed in time, the daily number of new infections could be significantly reduced in NYC. If all confirmed cases were hospitalized in time, the total number of deaths could be significantly reduced in NYC. Keeping a social distance and relaxing lockdown restrictions for people between the ages of 0 and 44 could not lead to a second wave of COVID-19 in NYC.

Effectivity of mesenchymal stem cells for bleomycin-induced pulmonary fibrosis: a systematic review and implication for clinical application.

Pulmonary fibrosis (PF) is a chronic, progressive, fibrotic interstitial disease of the lung with poor prognosis and without effective treatment currently. Data from previous coronavirus infections, such as the Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome, as well as current clinical evidence from the Coronavirus disease 2019 (COVID-19), support that SARS-CoV-2 infection may lead to PF, seriously impacting patient prognosis and quality of life. Therefore, effective prevention and treatment of PF will improve patient prognosis and reduce the overall social and economic burdens. Stem cells, especially mesenchymal stem cells (MSCs) have many great advantages, including migration to damaged lung tissue and secretion of various paracrine factors, thereby regulating the permeability of endothelial and epithelial cells, reducing inflammatory response, promoting tissue repair and inhibiting bacterial growth. Clinical trials of MSCs for the treatment of acute lung injury, PF and severe and critically ill COVID-19 are ongoing. The purpose of this study is to systematically review preclinical studies, explored the effectiveness of MSCs in the treatment of bleomycin (BLM)-induced pulmonary fibrosis and analyze the potential mechanism, combined with clinical trials of current MSCs for idiopathic pulmonary fibrosis (IPF) and COVID-19, so as to provide support for clinical research and transformation of MSCs. Searching PubMed and Embase (- 2021.4) identified a total of 36 preclinical studies of MSCs as treatment of BLM-induced acute lung injury and PF in rodent models. Most of the studies showed the MSCs treatment to reduce BLM-induced lung tissue inflammatory response, inflammatory cell infiltration, inflammatory cytokine expression, extracellular matrix production and collagen deposition, and to improve Ashcroft score. The results of present studies indicate that MSCs may serve as a potential therapeutic modality for the treatment of PF, including viral-induced PF and IPF.