It is always better to protect yourself from diseases than to take treatment afterwards. Although there is no vaccine to prevent dengue you can prevent the infection from spreading by taking simple measures:
Ensure that stagnant water containers are removed
Use mosquito repellant and cream on open parts of the body
Make sure windows and doors are closed after sunset
Wear full clothes when going out
Keep your water tank covered
Do not litter open places surrounding your house
Do not allow obstruction and collection of water
Do not stay outdoor after sunset
Do not ignore any symptoms of dengue-like fever and chills