scholarly journals Influenza vaccine failure in the tropics: a retrospective cohort study of waning effectiveness

2020 ◽  
Vol 148 ◽  
Author(s):  
B. E. Young ◽  
T. M. Mak ◽  
L. W. Ang ◽  
S. Sadarangani ◽  
H. J. Ho ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Cohort Study ◽  
Influenza Vaccine ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Influenza Infection ◽  
Winter Season ◽  
Temperate Climate ◽  
Vaccine Failure ◽  
Virus Activity

Abstract Influenza vaccine effectiveness (VE) wanes over the course of a temperate climate winter season but little data are available from tropical countries with year-round influenza virus activity. In Singapore, a retrospective cohort study of adults vaccinated from 2013 to 2017 was conducted. Influenza vaccine failure was defined as hospital admission with polymerase chain reaction-confirmed influenza infection 2–49 weeks after vaccination. Relative VE was calculated by splitting the follow-up period into 8-week episodes (Lexis expansion) and the odds of influenza infection in the first 8-week period after vaccination (weeks 2–9) compared with subsequent 8-week periods using multivariable logistic regression adjusting for patient factors and influenza virus activity. Records of 19 298 influenza vaccinations were analysed with 617 (3.2%) influenza infections. Relative VE was stable for the first 26 weeks post-vaccination, but then declined for all three influenza types/subtypes to 69% at weeks 42–49 (95% confidence interval (CI) 52–92%, P = 0.011). VE declined fastest in older adults, in individuals with chronic pulmonary disease and in those who had been previously vaccinated within the last 2 years. Vaccine failure was significantly associated with a change in recommended vaccine strains between vaccination and observation period (adjusted odds ratio 1.26, 95% CI 1.06–1.50, P = 0.010).

scholarly journals Influenza Vaccine Effectiveness in Preventing Severe Outcomes in Patients Hospitalized with Laboratory-Confirmed Influenza during the 2017–2018 Season. A Retrospective Cohort Study in Catalonia (Spain)

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1465
Author(s):  
Lesly Acosta ◽  
Nuria Soldevila ◽  
Nuria Torner ◽  
Ana Martínez ◽  
Xavier Ayneto ◽  
...  
Keyword(s):  
Cohort Study ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Vaccine Effectiveness ◽  
Public Hospitals ◽  
Categorical Variables ◽  
Type B ◽  
Icu Admission

Seasonal influenza is a common cause of hospital admission, especially in older people and those with comorbidities. The objective of this study was to determine influenza vaccine effectiveness (VE) in preventing intensive care admissions and shortening the length of stay (LOS) in hospitalized laboratory-confirmed influenza cases (HLCI) in Catalonia (Spain). A retrospective cohort study was carried out during the 2017–2018 season in HLCI aged ≥18 years from 14 public hospitals. Differences in means and proportions were assessed using a t-test or a chi-square test as necessary and the differences were quantified using standardized effect measures: Cohen’s d for quantitative and Cohen’s w for categorical variables. Adjusted influenza vaccine effectiveness in preventing severity was estimated by multivariate logistic regression where the adjusted VE = (1 − adjusted odds ratio) · 100%; adjustment was also made using the propensity score. We analyzed 1414 HLCI aged ≥18 years; 465 (33%) were vaccinated, of whom 437 (94%) were aged ≥60 years, 269 (57.8%) were male and 295 (63.4%) were positive for influenza type B. ICU admission was required in 214 (15.1%) cases. There were 141/1118 (12.6%) ICU admissions in patients aged ≥60 years and 73/296 (24.7%) in those aged <60 years (p < 0.001). The mean LOS and ICU LOS did not differ significantly between vaccinated and unvaccinated patients. There were 52/465 (11.2%) ICU admissions in vaccinated cases vs. 162/949 (17.1%) in unvaccinated cases. Patients admitted to the ICU had a longer hospital LOS (mean: 22.4 [SD 20.3] days) than those who were not (mean: 11.1 [SD 14.4] days); p < 0.001. Overall, vaccination was associated with a lower risk of ICU admission. Taking virus types A and B together, the estimated adjusted VE in preventing ICU admission was 31% (95% CI 1–52; p = 0.04). When stratified by viral type, the aVE was 40% for type A (95% CI -11–68; p = 0.09) and 25% for type B (95% CI -18–52; p = 0.21). Annual influenza vaccination may prevent ICU admission in cases of HLCI. A non-significantly shorter mean hospital stay was observed in vaccinated cases. Our results support the need to increase vaccination uptake and public perception of the benefits of influenza vaccination in groups at a higher risk of hospitalization and severe outcomes.

scholarly journals Clinical characteristics and outcome of influenza virus infection among adults hospitalized with severe COVID-19: a retrospective cohort study from Wuhan, China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xunliang Tong ◽  
Xiaomao Xu ◽  
Guoyue Lv ◽  
He Wang ◽  
Anqi Cheng ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Cohort Study ◽  
Clinical Features ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Cox Regression ◽  
Influenza Virus Infection ◽  
Chronic Respiratory Disease ◽  
Hospital Death ◽  
New City

Abstract Background Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that rapidly spreads worldwide and co-infection of COVID-19 and influenza may occur in some cases. We aimed to describe clinical features and outcomes of severe COVID-19 patients with co-infection of influenza virus. Methods Retrospective cohort study was performed and a total of 140 patients with severe COVID-19 were enrolled in designated wards of Sino-French New City Branch of Tongji Hospital between Feb 8th and March 15th in Wuhan city, Hubei province, China. The demographic, clinical features, laboratory indices, treatment and outcomes of these patients were collected. Results Of 140 severe COVID-19 hospitalized patients, including 73 patients (52.14%) with median age 62 years were influenza virus IgM-positive and 67 patients (47.86%) with median age 66 years were influenza virus IgM-negative. 76 (54.4%) of severe COVID-19 patients were males. Chronic comorbidities consisting mainly of hypertension (45.3%), diabetes (15.8%), chronic respiratory disease (7.2%), cardiovascular disease (5.8%), malignancy (4.3%) and chronic kidney disease (2.2%). Clinical features, including fever (≥38 °C), chill, cough, chest pain, dyspnea, diarrhea and fatigue or myalgia were collected. Fatigue or myalgia was less found in COVID-19 patients with IgM-positive (33.3% vs 50/7%, P = 0.0375). Higher proportion of prolonged activated partial thromboplastin time (APTT) > 42 s was observed in COVID-19 patients with influenza virus IgM-negative (43.8% vs 23.6%, P = 0.0127). Severe COVID-19 Patients with influenza virus IgM positive have a higher cumulative survivor rate than that of patients with influenza virus IgM negative (Log-rank P = 0.0308). Considering age is a potential confounding variable, difference in age was adjusted between different influenza virus IgM status groups, the HR was 0.29 (95% CI, 0.081–1.100). Similarly, difference in gender was adjusted as above, the HR was 0.262 (95% CI, 0.072–0.952) in the COX regression model. Conclusions Influenza virus IgM positive may be associated with decreasing in-hospital death.

scholarly journals Impact of B.1.351 (beta) SARS-CoV-2 variant on BNT162b2 mRNA vaccine effectiveness in long-term care facilities of eastern France: a retrospective cohort study

2021 ◽  
Author(s):  
Benjamin Lefevre ◽  
Laura Tondeur ◽  
Yoann Madec ◽  
Rebecca Grant ◽  
Bruno Lina ◽  
...  
Keyword(s):  
Cohort Study ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Long Term Care ◽  
Multivariable Analysis ◽  
Winter Season ◽  
Vaccine Effectiveness ◽  
Term Care ◽  
Care Facilities

Abstract Background: We aimed to assess the effectiveness of the BNT162b2 mRNA vaccine against B.1.351 (beta) variant among residents of long-term care facilities (LCTFs) in eastern France. Methods: We used routinely collected surveillance and COVID-19 vaccination data to conduct a retrospective cohort study of SARS-CoV-2 B.1.351 infection incidence and vaccine effectiveness among LCTFs residents in eastern France between 15 January and 19 May 2021. Data from secondary RT-PCR screening were used to identify B.1.351 variants. Findings: Included in our analysis were 378 residents from five LCTFs: 287 (76%) females, with median (IQR) age of 89 (83-92) years. Two B.1.351 outbreaks took place in LTCFs in which more than 70% of residents had received two doses of BNT162b2 mRNA vaccine, which included 11 cases of severe disease and six deaths among those who had received two doses. Vaccine effectiveness (95% CI) seven days after the second dose of vaccine was 49% (14-69) against any infection with B.1.351 and 86% (67-94) against severe forms of COVID-19. In multivariable analysis, females were less likely to develop severe forms of disease (IRR = 0.35, 95% CI = 0.20-0.63). Interpretation: We observed reduced vaccine effectiveness associated with B.1.351, as well as B.1.351 outbreaks in two LTCFs among individuals who had received two doses of vaccine. Our findings highlight the need to maintain SARS-CoV-2 surveillance in these high-risk settings beyond the current COVID-19 mass vaccination campaign, and advocate for a booster vaccine dose prior to the next winter season.

scholarly journals Clinical characteristics and outcome of influenza virus infection among adults hospitalized with severe COVID-19: A retrospective cohort study from Wuhan, China

2020 ◽  
Author(s):  
Xunliang Tong ◽  
Xiaomao Xu ◽  
Guoyue Lv ◽  
He Wang ◽  
Anqi Cheng ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Cohort Study ◽  
Clinical Features ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Influenza Virus Infection ◽  
Clinical Feature ◽  
Risk Of Death ◽  
New City ◽  
Characteristic Features

Abstract Background Coronavirus disease 2019 (COVID-19) is an emerging infection disease that rapidly spreads worldwide. Co-infection may occur in some cases of COVID-19, like influenza virus and so on. Clinical features and outcomes of severe COVID-19 patients with co-infection of influenza virus need to be noticed.Methods Retrospective cohort study was performed and total of 140 patients with severe COVID-19 was enrolled in designated wards of Sino-French New City Branch of Tongji Hospital between Feb 8th and March 15th in Wuhan, Hubei province, China. The demographic, clinical features, laboratory indices, treatment and outcomes of these patients were collected and analyzed.Results Of 140 severe COVID-19 hospitalized patients, 73 patients were with median age of 66 years old with identification of influenza virus IgM-positive and 67 patients were with median age of 62 years old in influenza virus IgM-negative. Nearly half of severe COVID-19 patients in this research are male. Majority of the severe COVID-19 patients had chronic underlying conditions. Wheeze was the clinical feature of severe COVID-19 patients with influenza IgM-positive (26.4% vs 9.0%, P = 0.008). On contrary, fatigue or myalgia was the feature of the COVID-19 patients without IgM-positive (38.4% vs 58.2%, P = 0.019). Increased levels of ferritin and prolonging APTT were showed in severe COVID-19 patients without influenza IgM-positive compared with patients in other group with significant differences. Death rate in the group of severe COVID-19 patients with influenza IgM-positive is lower than it in other group with significant differences (4.1% vs 14.9%, P = 0.040). In univariate regression analysis, several factors were associated with higher risk of death, which included LDH, troponin, NT-proBNP, D-dimer, PT, APTT, lymphocytes, platelet and eGFR. However, influenza virus IgM positive was associated with lower risk of death.Conclusions Characteristic features of patients with severe COVID-19 with influenza virus IgM-positive were described. Co-infection may occur during the pandemic of COVID-19, and we need to improve our understanding in order to confront this crisis in the future.

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