Key points
- Dengue is a disease caused by four distinct, but closely related dengue viruses, DENV-1–4. People can be infected with dengue multiple times.
- For people who have not had dengue before, the vaccine can increase the risk of severe infection.
- Learn how dengue vaccine eligibility relates to previous infection and when vaccination is recommended.
People without previous dengue infection
In people who have not had dengue before, the vaccine could increase the risk of hospitalization or severe dengue if a person gets dengue after vaccination.
- If you vaccinate a person who has never been infected with dengue virus, they skip the first, natural infection.
- If the person is then infected after vaccination, they will experience an infection that is similar to the second dengue virus infection, which poses the highest risk for severe disease.
- The mechanism causing greater severity of the second dengue virus infection includes antibody-dependent enhancement, which can lead to plasma leakage and severe disease.
Remember
DO NOT vaccinate a person without laboratory evidence of previous dengue virus infection.
People with previous dengue infections
- If you vaccinate a child who has been previously infected with dengue virus, the child skips the second dengue virus infection.
- If infected after vaccination, the child will experience an infection that is similar to the third or fourth dengue virus infection, which are the lowest risk for severe disease.
- Children and adolescents 9–16 years old with laboratory confirmation of previous dengue virus infection and living in dengue-endemic areas are eligible for the Dengvaxia dengue vaccine.