Diseases beginning with C
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.
Chickenpox (Varicella)
Routine vaccineDisease
A highly contagious infection caused by varicella-zoster virus.
Symptoms
Itchy blister-like rash, fever, tiredness, headache, and loss of appetite.
Typical duration
The rash commonly lasts about four to seven days; people are contagious before and until lesions crust over.
How serious is it?
Usually mild in children, but pneumonia, brain inflammation, bloodstream infection, hospitalization, and death can occur.
Treatment & management
Symptom care is common; antivirals may be recommended early for people at higher risk. Avoid aspirin in children with chickenpox.
Vaccine: who and when?
Products: Varivax (varicella-only) and ProQuad (MMRV combination for eligible children). CDC recommends two doses, usually at 12-15 months and 4-6 years. People age 13 and older without immunity generally receive two Varivax doses at least 28 days apart.
Chikungunya
Travel or special-risk vaccineDisease
A mosquito-borne viral disease found in parts of the Americas, Africa, Asia, and other regions.
Symptoms
Sudden fever and often severe joint pain; headache, muscle pain, joint swelling, or rash may occur.
Typical duration
Most improve within a week, but joint pain can persist for months or longer.
How serious is it?
Severe disease is uncommon but risk is higher for newborns, older adults, and people with certain medical conditions.
Treatment & management
No specific antiviral treatment. Rest, fluids, and clinician-guided symptom relief are used; dengue should be ruled out before some pain medicines.
Vaccine: who and when?
Product: VIMKUNYA, a single-dose, non-live vaccine licensed for people age 12 and older. CDC recommends it for certain travelers to outbreak areas and laboratory workers, and says it may be considered for some long-stay travelers to elevated-risk areas.
Cholera
Travel vaccineDisease
An intestinal infection usually acquired from food or water contaminated with Vibrio cholerae.
Symptoms
Many infections are mild; severe cases cause profuse watery diarrhea, vomiting, leg cramps, and rapid dehydration.
Typical duration
Symptoms commonly begin within hours to five days of exposure.
How serious is it?
Severe dehydration can become fatal within hours without treatment.
Treatment & management
Immediate oral rehydration is central; severe cases need intravenous fluids and sometimes antibiotics.
Vaccine: who and when?
Product: Vaxchora, a single-dose live oral vaccine. In the United States it is licensed for ages 2-64 and is given at least 10 days before travel when CDC recommends vaccination for an area with active cholera transmission.
COVID-19
Seasonal/risk-based vaccineDisease
A respiratory illness caused by SARS-CoV-2.
Symptoms
Fever or chills, cough, sore throat, congestion, fatigue, body aches, headache, or loss of taste or smell; symptoms vary widely.
Typical duration
Many acute cases improve within days to a few weeks; some people develop longer-lasting symptoms (Long COVID).
How serious is it?
Can cause pneumonia, hospitalization, blood clots, organ complications, and death, especially in higher-risk groups.
Treatment & management
Early antiviral treatment may reduce severe disease in eligible higher-risk patients. Seek prompt medical advice because treatment windows are short.
Vaccine: who and when?
Current U.S. products include Comirnaty, Spikevax, MNEXSPIKE, and Nuvaxovid. The recommended number and timing of 2026-2027 doses depend on age, immune status, previous doses, and current CDC guidance, so use the current schedule rather than an older fixed dose count.
Last reviewed against official U.S. sources: September 5, 2026. This page provides general education, not medical advice.