Disease & Vaccine A–Z

Diseases beginning with D

U.S.-focused summaries with current official guidance links. For a diagnosis, personal vaccine schedule, pregnancy advice, or urgent symptoms, speak with a qualified clinician.

Dengue

Mosquito-borne disease

Disease

A viral infection spread mainly by Aedes mosquitoes.

Symptoms

Fever with headache, eye pain, muscle or joint pain, nausea, vomiting, or rash.

Typical duration

Symptoms typically last two to seven days; warning signs can appear as the fever falls.

How serious is it?

Severe dengue can cause shock, internal bleeding, organ damage, and death. Warning signs need urgent care.

Treatment & management

No specific antiviral treatment. Fluids and monitoring are important; avoid aspirin and ibuprofen until dengue is ruled out.

Vaccine: who and when?

Former U.S. product: Dengvaxia, a three-dose vaccine that had narrow eligibility for some children with laboratory-confirmed previous dengue infection in endemic U.S. areas. U.S. distribution ended and remaining doses expired in August 2026; no dengue vaccine is currently available in the United States.

Check the current CDC guidance for Dengue →

Diphtheria

Routine vaccine

Disease

A bacterial infection that can affect the throat and airways or, less commonly, the skin.

Symptoms

Sore throat, mild fever, swollen neck glands, weakness, and a thick gray coating in the nose or throat.

Typical duration

Symptoms usually begin two to five days after exposure; illness and recovery can last weeks.

How serious is it?

The toxin can damage the heart and nerves and may be fatal. Suspected respiratory diphtheria is an emergency.

Treatment & management

Diphtheria antitoxin and antibiotics are used promptly, with isolation and management of close contacts.

Vaccine: who and when?

Products include Daptacel and Infanrix (DTaP) for the five-dose childhood series; Boostrix and Adacel (Tdap); Tenivac (Td); and combination vaccines such as Pediarix, Pentacel, Vaxelis, Kinrix, and Quadracel. CDC recommends age-appropriate primary doses, Tdap during every pregnancy, and adult boosters.

Check the current CDC guidance for Diphtheria →

Cost and access: Patient cost varies by insurance, provider, location, and eligibility. Many recommended vaccines are covered with no out-of-pocket cost under qualifying plans, and eligible children may receive vaccines through the Vaccines for Children program. CDC price lists are purchasing benchmarks—not guaranteed patient prices. CDC price and program context.

Last reviewed against official U.S. sources: September 5, 2026. This page provides general education, not medical advice.