Influenza imposes a significant disease burden on society and individuals annually, and influenza vaccination is considered a significant public health measure to prevent influenza and reduce influenza-related severe disease and death. The low influenza vaccination rate in China is partly due to certain factors affecting the willingness and behavior of individuals to receive them. Scientific research and targeted interventions on these factors can effectively improve the vaccination situation. Commonly used individual-level theoretical models for influenza vaccination behavior include the health belief model, protection motivation theory, and theory of planned behavior. This study reviews theoretical models commonly employed in researching influenza vaccination willingness and behavior. An overview of these practical applications and challenges models is presented to provide references for relevant research and intervention programs in China.

Objective:To explore the relationship between prognostic nutritional index (PNI) and cognitive impairment (CI) in maintenance hemodialysis (MHD) patients.Methods:It was a multicenter cross-sectional study that included adult patients who received MHD treatment at 18 hemodialysis centers in Guizhou province from June to October 2020 as the study subjects. Cognitive function was assessed with the mini-mental state examination score. According to the scale score, the patients were divided into CI group (≤27 scores) and non-CI group (>27 scores), and the differences between the two groups were compared. The patients were divided into Q1 (PNI<38.0), Q2 (38.0≤PNI<40.4), Q3 (40.4≤PNI<43.0), and Q4 (PNI≥43.0) groups based on the PNI quartiles. The PNI was estimated based on the serum albumin and lymphocyte count. Multivariate logistic regression analysis was used to analyze the correlation between PNI and CI, and subgroup analysis was conducted.Results:A total of 1 740 MHD patients were enrolled in the study, with 1 021 males (62.9%) and 719 females (37.1%). The age was (55±15) years old. There were 411 patients (23.6%) with CI. The age, C-reactive protein, and the proportions of females, current smoking/drinking and diabetes in the CI group were significantly higher than those in the non-CI group, and the education level, blood lymphocyte count, blood prealbumin, serum albumin, serum creatinine, blood uric acid and PNI were significantly lower than those in the non-CI group (all P<0.05). The risk of CI in Q1 group was 1.88 times higher than that of Q4 group after adjusting for confounding factors such as sex, age, body mass index, education level, comorbidities, current smoking/drinking, dialysis age and C-reactive protein ( OR=1.88, 95% CI 1.17-2.30, P=0.008). Subgroup analysis showed that there was an interaction between age and PNI on CI ( P=0.040 for interaction). Q1 group in the patients aged 18 to 45 years old had a higher risk of CI compared to Q4 group ( OR=3.30, 95% CI 1.19-9.10). Conclusions:Low PNI significantly increases the risk of CI in MHD patients, in particularly in the patients aged <45 years old.