Effects of influenza vaccine and sun exposure time against laboratory-confirmed influenza hospitalizations among young children during the 2012-13 to 2015-16 influenza seasons.

BACKGROUND: Influenza is a major cause of acute respiratory infection burden worldwide, leading to many hospitalizations. An annual influenza vaccine is believed to be the best way to prevent influenza-related illnesses. We focused on the efficacies of other possible preventive measures such as increasing sun exposure time and dietary supplements to prevent these illnesses. METHODS: We conducted a matched-pair case-control study along with the Taiwan Pediatric Infectious Disease Alliance. We included influenza-related hospitalized patients with age ranging from 6 months to 5 years during the 2012-2013, 2013-2014, 2014-2015, and 2015-2016 influenza seasons. The controls were comparable to cases in age, sex, and residential area and had no influenza-related hospitalization records in the same season. We extracted data from vaccination histories and got the patients' guardians to complete questionnaires. Data were analyzed using conditional logistic regression. RESULTS: We enrolled 1514 children (421 influenza-infected cases and 1093 controls) in the study. We found seasonal influenza vaccination to be an independent protective factor against hospitalizations owing to influenza [p < 0.01; odds ratio (OR), 0.427; 95% confidence interval (CI), 0.306-0.594]. Children with mean sun exposure time of >7 h/week had a significantly lower risk of influenza-related hospitalizations than those with the mean sun exposure time of ≤7 h/week (p < 0.05; OR, 0.667; 95% CI, 0.491-0.906). CONCLUSIONS: Seasonal influenza vaccination effectively prevents influenza-related hospitalizations in children aged ≤5 years. Besides, >7 h of sun exposure/week may also be associated with lower risk of influenza-related hospitalizations in children.

Entrapment of an adenine derivative by a photo-irradiated uracil-functionalized micelle confers controlled self-assembly behavior.

HYPOTHESIS: Invoking cooperative assembly of the uracil-functionalized supramolecular polymer BU-PPG [uracil end-capped poly(propylene glycol)] upon association with the nucleobase adenine derivative A-MA [methyl 3-(6-amino-9H-purin-9-yl)propanoate] as a model drug provides a new concept to control and tune the properties of supramolecular complexes and holds significant potential for the development of safer, more effective drug delivery systems. EXPERIMENTS: BU-PPG and A-MA were successfully developed and exhibited specific recognition and high affinity, which enabled reversible complementary adenine-uracil (A-U) hydrogen bonding-induced formation of spherical micelles in aqueous solution. The self-assembly and controllable A-MA release behavior of BU-PPG/A-MA micelles were studied using morphological analysis and optical and light scattering techniques to investigate the effect of photoirradiation and temperature on the complementary hydrogen bond interactions between BU-PPG and A-MA. FINDINGS: The resulting micelles possess unusual physical properties, including controlled photoreactivity kinetics, controllable self-assembled morphology and low cytotoxicity in vitro, as well as reversible temperature-responsive behavior. Importantly, irradiated micelles exhibited excellent long-term structural stability under normal physiological conditions and serum disturbance. Increasing the temperature triggered rapid release of A-MA by disrupting A-U complexes. These findings represent an entirely new, promising strategy for the development of multi-controlled release drug delivery nanocarriers based on complementary hydrogen bonding interactions.