ABSTRACT
INTRODUCTION: The association between influenza vaccination and COVID-19 remains controversial. This meta-analysis aimed to investigate whether influenza vaccination reduces the susceptibility and severity of SARS-CoV-2 infection. METHODS: A systematic literature search of PubMed, Web of Science, the Cochrane Library, Embase, China National Knowledge Infrastructure, SinoMed, Wanfang Data Knowledge Service Platform, and China Science and Technology Journal VIP Database was conducted from database inception to August 2021. The pooled RR with 95% CI was used to estimate the effect of influenza vaccination on COVID-19. The I2 value was used to assess heterogeneity. If I2>50%, the random-effects model was used as the pooling method. RESULTS: A total of 23 published articles with 1,037,445 participants were identified. This meta-analysis showed that influenza vaccination was associated with reduced risk of COVID-19 infection (RR=0.83, 95% CI=0.76, 0.90) and hospitalization (RR=0.71, 95% CI=0.59, 0.84), although not significantly associated with intensive care unit admission and death (risk of intensive care unit admission: RR=0.93, 95% CI=0.64, 1.36; risk of death: RR=0.83, 95% CI=0.68, 1.01). Further analysis suggested that the tetravalent influenza vaccine may be associated with a reduced risk of COVID-19 infection (RR=0.74, 95% CI=0.65, 0.84). DISCUSSION: The results suggest that influenza vaccination is associated with reduced susceptibility to or disease severity of COVID-19 and that influenza vaccination may reduce the risk of COVID-19 and improve clinical outcomes.
Subject(s)
COVID-19 , Influenza Vaccines , Influenza, Human , COVID-19/epidemiology , COVID-19/prevention & control , Humans , Influenza, Human/epidemiology , Influenza, Human/prevention & control , SARS-CoV-2 , VaccinationABSTRACT
OBJECTIVES: The purpose of this study was to compare and determine whether there were any differences in clinical outcomes between pregnant and non-pregnant women who had been infected with COVID-19. METHODS: A literature search was performed in 9 databases on November 20, 2021. The relative risk (RR) with 95% confidence interval (95% CI) was used to estimate the effect of pregnancy on COVID-19 outcomes. The I square value was used to assess heterogeneity, and the random or the fixed-effects model were adopted. Sensitivity and publication bias analyses were performed. RESULTS: This study included 8 published studies with 859,278 COVID-19 female patients. The incidences of fever and cough among pregnant women with COVID-19 were 19.07% and 28.79%, respectively. Pregnancy was associated with significantly increased risks of intensive care unit (ICU) admission (RR = 2.23, 95% CI = 1.58-3.16) and ventilation (RR = 2.13, 95% CI = 1.06-4.28), but was not associated with a statistically significant increase in mortality. CONCLUSIONS: Our results suggest that pregnant women with COVID-19 have a significantly higher probability of being hospitalized to the ICU and ventilation than non-pregnant women with COVID-19. To avoid these adverse outcomes, pregnant women should take precautions (for example, reduce going out, maintain social distance, and wear a mask) to avoid COVID-19 infection. Finally, additional research into the fetal outcomes is required to better investigate the impact of COVID-19 on pregnancy.