Respiratory syncytial virus vaccine
A respiratory syncytial virus vaccine (RSV vaccine) is a vaccine which prevents infection by respiratory syncytial virus. , no licensed vaccine against RSV exists. Attempts to develop an RSV vaccine began in the 1960s with an unsuccessful inactivated vaccine developed by exposing the RSV virus to formalin (formalin-inactivated RSV (FI-RSV)). Unfortunately, this vaccine induced a phenomenon that came to be known as vaccine-associated enhanced respiratory disease (VAERD), in which children who had not previously been exposed to RSV and were subsequently vaccinated would develop a severe form of RSV disease if exposed to the  virus itself, including fever, wheezing, and bronchopneumonia. Some eighty percent of such children (vs. 5% of virus-exposed controls) were hospitalized, and two children died of lethal lung inflammatory response during the first natural RSV infection after vaccination of RSV-naive infants. This disaster hindered vaccine development for many years to come. A 1998 paper reported that research toward developing a vaccine had advanced greatly over the previous 10 years. The desired vaccine would prevent lower respiratory infection from RSV in at-risk populations and if possible be useful in other populations with less risk. Twenty years later, a 2019  paper similarly claimed that research toward developing a vaccine had advanced greatly over the prior 10 years. The same study predicted that a vaccine would be available within 10 years. The current types of vaccines which are in research are particle-based vaccines, attenuated vaccines, mRNA vaccines, protein subunit vaccines, or vector-based vaccines. A vaccine called GSK3888550A and developed by GlaxoSmithKline (GSK) entered phase 3 clinical trials in November 2020. Barney S. Graham and Peter Kwong of the National Institute of Allergy and Infectious Diseases' Vaccine Research Center, along with Jason McLellan, a former postdoctoral researcher at VRC and  a professor at The University of Texas at Austin, spearheaded its development. The vaccine's antigen, a stabilized version of the RSV F protein, was developed using structure-based vaccine design. In August 2021, Moderna received US FDA fast track designation for their Respiratory Syncytial Virus Vaccine.