After recovering from an infection with one dengue serotype, a person has immunity against that particular serotype. Does infection with one serotype protect against future dengue infections with the other serotypes? Individuals are protected from infections with the remaining three serotypes for two to three months after the first dengue infection. Unfortunately, it is not long-term protection. After that short period, a person can be infected with any of the remaining three dengue serotypes. Researchers have noticed that subsequent infections can put individuals at a greater risk for severe dengue illnesses than those who have not been previously infected.