Disease & Vaccine A–Z

Diseases beginning with S

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.

Shingles

Routine/risk-based vaccine

Disease

Reactivation of the chickenpox virus, causing a painful rash along a nerve pathway.

Symptoms

Pain, burning, tingling, itching, and a one-sided blistering rash; headache, chills, or upset stomach may occur.

Typical duration

The rash often clears in two to four weeks, but nerve pain can persist for months or years.

How serious is it?

Can cause prolonged nerve pain, eye damage, hearing problems, skin infection, or neurologic complications.

Treatment & management

Prescription antivirals work best when started early; pain treatment and eye evaluation may also be needed.

Vaccine: who and when?

Product: Shingrix, a two-dose recombinant vaccine recommended for adults age 50 and older and immunocompromised adults age 19 and older. The usual interval is 2-6 months, although immunocompromised people may receive the second dose after 1-2 months when faster protection is helpful.

Check the current CDC guidance for Shingles →

Smallpox

Special-risk vaccine

Disease

A severe variola virus disease eradicated worldwide; no naturally occurring cases have occurred since 1977.

Symptoms

Historically caused high fever, severe aches, vomiting, and a deep, progressive pustular rash.

Typical duration

Historically, illness developed over several weeks.

How serious is it?

Was often fatal and could cause blindness and permanent scarring. Any suspected case is a public-health emergency.

Treatment & management

National response plans include isolation, specialist care, antivirals, vaccination, and close-contact management.

Vaccine: who and when?

Products include ACAM2000, a one-dose replicating vaccinia vaccine, and JYNNEOS, a two-dose non-replicating vaccine also used for mpox. Smallpox vaccination is not routine and is reserved for specified laboratory, occupational, response, or emergency use under public-health direction.

Check the current CDC guidance for Smallpox →

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.