Varicella and herpes zoster

• 1950Cortisone acetate approved (FDA)
• 1955Prednisone approved (FDA)
• 1955Prednisolone approved (FDA)
• 1958Dexamethasone approved (FDA)
• 1959Dexamethasone phosphoric acid approved (FDA)
• 1982Acyclovir approved (FDA)
• 1994Famciclovir approved (FDA)
• 1995Valacyclovir approved (FDA)
• 2006Varicella zoster virus, live attenuated approved (FDA)
• 2018Varicella zoster virus envelope glycoprotein e approved (FDA)

Trials started per year, stacked by phase (darker = later phase). Source: ClinicalTrials.gov via Clin2, which tracks studies recruiting in recent years — early years undercount.

Varicella and herpes zoster are preventable in most cases: safe, effective vaccines block most chickenpox and shingles, and antivirals can shorten illness when it occurs. In countries with routine vaccination, cases and deaths have fallen steadily; where access is limited, the disease remains common. The approval of prednisone in 1955 gave clinicians a key tool for managing severe inflammatory complications, while modern vaccines offer the greatest protection globally. Research continues, with many trials underway to improve prevention and treatment.

How effective are the vaccines?

The varicella vaccine prevents most chickenpox, and the recombinant zoster vaccine prevents most shingles. Both are safe and widely used. No vaccine is perfect, but breakthrough cases are usually milder.

Can shingles be treated?

Antiviral drugs can shorten a shingles episode and reduce complications like postherpetic neuralgia, especially when started within a few days of rash onset. They do not cure the underlying virus but lessen its impact.

Are there new studies for this disease?

Seventy-two trials have started in the last five years, including fourteen phase-3 studies, and seventy-one trials are actively exploring improved vaccines, antiviral strategies, and ways to prevent reactivation.

Why do some people still get chickenpox?

In places without routine vaccination, the virus spreads easily among children. Even in vaccinated populations, mild breakthrough cases can occur, but severe disease and deaths are now much rarer.

Can the virus return after chickenpox?

Yes. The varicella-zoster virus stays dormant in nerve tissue and can later reactivate as shingles, especially in older adults. The shingles vaccine significantly reduces this risk and its complications.