In this paper, we study a class of fourth-order boundary value problems with integral boundary conditions. The nonlinearity may have time-singularity and change sign. Moreover, it satisfies general polynomial growth conditions. A new topological approach is applied to prove the existence of at least two nonnegative classical solutions. An example of application illustrates the existence result.

This paper discusses the existence of solutions to fourth order nonlinear boundary value problem involving systems of differential equations and two point boundary conditions. The nonlinearity f ∈ C ([0,1] × Rn+ × Rn × Rn × Rn, Rn)considered in this paper includes derivatives up to order three. Using recent fixed point results for the sum of two operators, we impose a growth condition on f to establish a new existence criteria that ensure the existence of at least one and the existence of at least two nonnegative solutions.

Background: Broadly defined, health technology assessment (HTA) is the systematic evaluation of medical technologies. This approach takes in to account effectiveness of the technologies, social and ethical aspects and efficiency as well as. A large number of countries globally have not yet implemented the use of HTA because of varying reasons. \ud Purpose: The study aims to show the correlation between the presence of official HTA body and the socioeconomic features. \ud Material/Methods: In a 3-month period we used the method of document analysis from different sources regarding the presence of HTA bodies all over the world. A process for verification of the information used was developed and implemented. The same process was used to derive the presented information from the analysis. \ud Results: About one in two countries have formal HTA process to inform decision making, in which they systematically collect data and consider the impacts of a particular health technology or intervention. However, almost а quarter of the studied countries are located in Europe, most of them (86%) have an official HTA agency that operates in the country. We found that 80% of HTA bodies all over the World are located in countries with high income rate and most of them are European.\ud Conclusions It was found that it is possible to establish a correlation between the socio-economic parameters of a country and the existence of an active HTA agency in it

Bulgaria is assumed to be the country with the lowest COVID-19 vaccination coverage in the EU. The present study aims to highlight the economic impact of vaccine hesitancy. The period analyzed is from 1 January 2021 to 31 December 2021, examining hospitalization costs for COVID-19 patients, vaccine application costs, and vaccine type and dose administered. Results demonstrate a net impact of BGN 97 686 089 (€49 946 104) if 30% of the eligible population had been vaccinated and BGN 146 529 133 (€74 919 156) if a 45% rate had been achieved. In addition, 5.1 million unused doses were scrapped—more than those administered. The public health impact of vaccine hesitancy in Bulgaria led to a preventable medical crisis, substantial economic losses due to avoidable hospitalizations, and significant additional costs associated with the destruction of unused vaccines.