A security system, method and computer program product are provided. According to certain embodiments, an apparatus for determining a risk of retinopathy of prematurity in a patient may include a processing unit. The cross conveyor is supported by the frame. The third front and rear shaft bearings are arranged with the second shaft bearing between them, and fourth shaft bearing is disposed between the first front and second shaft bearings. The antigens are also useful in vaccine compositions effective in methods for preventing HEV infection.