Vaccinations are not required before coming into the kingdom. However, it is recommended that visitors, especially Hajj and Omrah visitors, be vaccinated for meningitis, malaria, polio, hepatitis, and avian and swine influenza, according to the destination they will be visiting. This is primarily to protect visitors against any infections carried by other visitors from countries where these diseases are found.

Health Guidelines
Of late, a number of cases being infected with the Middle East Respiratory Syndrome (MERS) Coronavirus have been recorded in Saudi Arabia. The Ministry of Health (MoH) is seeking to contain the risk of the spread of infection through awareness programs among citizens and residents alike, as well as taking preventative measures at airports and border entry points to limit its spread. The MoH has also established specialized units under the MERS Control Center to combat the syndrome.
For more details kindly visit the Ministry of Health website: 

Protection from the Sun
Temperatures continue to rise in most parts of the Kingdom in summer, where it reach up to 50 ° C, which can cause high body temperature, or the so-called (heat stroke).

Treatment of heat stroke depends on taking the injured away from the sun and laying him/her in a shaded and cold place until the temperature gets back to normal. The patient has to drink large amount of cold water thus to maintain the brain and vital body functions healthy.

To avoid this, light-colored and baggy clothes shall be worn, fluids shall be drunk and the exposure to sunlight for a long time must be avoided, and staying in shaded and good ventilated places is recommended.

The kingdom of Saudi Arabia is full with a wide range of (land and sea) animals, which have great capacity to adapt to live in such an environment. There are many wild mammals, birds, reptiles, insects and spiders that have adapted to the desert life. The number of such animals and creatures has been decreased, especially big-sized ones, such as deer since the fifties of the fourteenth century (AH) due to over-hunting. However, the establishment of protected areas in several places of the kingdom has contributed in the protection of endangered animals, such as Oryx and deer and others, in addition to domesticated animals, such as, camels, cows, sheep and goats, and transport animals such as, horses, donkeys, and so on.