Zika

Currently investigational — no approved indications. Target populations for future vaccine: women of childbearing age in endemic areas (Latin America, Caribbean, Southeast Asia, Pacific Islands). Travelers to endemic areas, especially pregnant women or those planning pregnancy. Military personnel deployed to endemic regions. Laboratory workers handling Zika virus. WHO declared Zika a PHEIC in 2016 (ended November 2016); continued surveillance ongoing.

Investigational — specific contraindications will depend on the platform approved. General expectations: mRNA and inactivated candidates expected to have fewer contraindications. Any future live attenuated candidates would be contraindicated in pregnancy and immunocompromised. All candidates: severe allergy to components.

Investigational. Phase 1/2 data: VRC-ZKADNA090: injection site pain (~50%), fatigue, headache, myalgia — generally mild and self-limiting. mRNA-1893: injection site pain (56–78%), fatigue (30–40%), headache (25–35%), myalgia (20%). ZPIV: injection site pain (35%), fatigue, headache. No serious adverse events attributed to any candidate in published trials.

VRC-ZKADNA090 (DNA): 89% seroconversion, neutralizing titers ~1:100 (PRNT50). mRNA-1893: 94% seroconversion after 2 doses, higher GMT than DNA candidate. ZPIV: 92% seroconversion but requires alum adjuvant. No efficacy trials against clinical disease completed (low incidence post-2016 prevents traditional phase 3 trials — adaptive designs under consideration).

Investigational. Co-administration studies planned but limited data. Theoretical considerations: mRNA/inactivated platforms expected to be co-administrable with routine vaccines. Live attenuated: standard 28-day spacing with other live vaccines.

Key target population: women of childbearing age due to congenital Zika syndrome. mRNA and inactivated candidates expected to be safe in pregnancy (but no data yet). Live attenuated candidates: expected contraindication in pregnancy. Pre-conception vaccination strategy likely to be recommended.

No licensed vaccine available as of 2026. Prevention relies on mosquito avoidance (DEET, permethrin-treated clothing, bed nets), sexual transmission prevention (condoms for 3 months after travel for both sexes — CDC; conception timing: wait 3 months for men, 2 months for women after symptom onset/travel), and travel avoidance for pregnant women. WHO maintains Zika virus in R&D Blueprint priority list. Clinical development slowed post-2016 epidemic due to declining incidence making efficacy trials challenging.