**9. Future strategies**

Vaccines are still considered the great hope in disease prevention and control strategies. However, among respiratory viruses there has been little progress, only influenza has vaccines. A different approach is needed in developing new vaccines with longer term efficacy and broader response. Current vaccines are prone to changing antigenicity and need to be administered annually. Vaccine development has been in progress for decades but faces numerous technical challenges. Respiratory viruses such as RSV, PIV and hMPV initiate incomplete immune responses and so reinfections tend to occur. The pace of progress is slow both for Both live-attenuated and subunit vaccines. It may be years before such vaccines are available in the market place. However, once available then adult immunization may offer protection to young infants as is the case with influenza vaccines [80].
