This enhanced form of the disease led to 80% hospitalization in the recipients of FIRSV compared to 5% in the control group. Additionally, 2 fatalities occurred among the vaccine recipients upon reinfection in subsequent years. Subsequent attempts to develop an attenuated live virus vaccine with optimal immune response and minimal reactogenicity have been unsuccessful. Further research on animal subjects suggested that intravenously administered immunoglobulin with high RSV neutralizing activity can protect against RSV infection. In 1995, the U.S. Food and Drug Administration (FDA) approved the use of RespiGam (RSV-IGIV) for the prevention of serious lower respiratory tract infection caused by RSV in children younger than 24 months of age with bronchopulmonary dysplasia or a history of premature birth. The success of the RSV-IGIV demonstrated efficacy in immunoprophylaxis and prompted research into further technologies. Thus, Palivizumab was developed as an antibody that was found to be fifty times more potent than its predecessor. This antibody has been widely used for RSV since 1998 when it was approved. Palivizumab, originally known as MEDI-493, was developed as an RSV immune prophylaxis tool that was easier to administer and more effective than the current tools of that time (the 1990s). It was developed over a 10-year period by MedImmune Inc. by combining human and mouse DNA. Specifically, antibody production was stimulated in a mouse model following immunization with RSV. The antibody-producing B cells were isolated from the mouses spleen and fused with mouse myeloma cell lines.
Cracked tooth syndrome (CTS) is where a tooth has incompletely cracked but no part of the tooth has yet broken off. Sometimes it is described as a greenstick fracture. The symptoms are very variable, making it a notoriously difficult condition to diagnose. Classification and definition
Cracked tooth syndrome could be considered a type of dental trauma and also one of the possible causes of dental pain. One definition of cracked tooth syndrome is "a fracture plane of unknown depth and direction passing through tooth structure that, if not already involving, may progress to communicate with the pulp and/or periodontal ligament." Signs and symptoms
The reported symptoms are very variable, and frequently have been present for many months before the condition is diagnosed. Reported symptoms may include some of the following:

Sharp pain when biting on a certain tooth, which may get worse if the applied biting force is increased. Sometimes the pain on biting occurs when the food being chewed is soft with harder elements, e.g. seeded bread. "Rebound pain" i.e. sharp, fleeting pain occurring when the biting force is released from the tooth, which may occur when eating fibrous foods. Pain on biting
Pain when grinding the teeth backward and forward and side to side. Sharp pain when drinking cold beverages or eating cold foods, lack of pain with heat stimuli. Pain when eating or drinking sugary substances.