Japanese Encephalitis — CDC Yellow Book
Cited in 2 Likelier entries (1 risk, 1 decision).
Used in 2 entries
For each citing entry, the verbatim excerpt and Likelier's calculation notes (how the source's number was converted to the lifetime-probability framing) are shown below. Click through to read the full claim ledger.
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- Statistic
Overall incidence of JE among travelers from non-endemic countries is estimated at <1 case per 1 million travelers; short-term (<1 month) travelers restricted to major urban areas are at minimal risk; long-term rural travelers may approach the susceptible pediatric resident rate of 6-11 cases per 100,000 children per year.
“"The overall incidence of JE among people from non-endemic countries traveling to Asia is estimated to be <1 case per 1 million travelers. … Shorter-term (e.g., <1 month) travelers whose visits are restricted to major urban areas are at minimal risk for JE. … Expatriates and travelers staying prolonged periods in rural areas with active JE virus transmission might be at similar risk as the susceptible pediatric resident population, which is 6–11 cases per 100,000 children per year."”
Calculation notes
CDC Yellow Book gives the headline traveler figure (<1 per million) used as the upper edge of the uncertainty band, and the long-term rural figure (6–11 per 100,000 per year) used as the anchor for the "long-term rural traveler, 1+ month wet season" row of regional_breakdown. The short-term urban point estimate of 5 × 10⁻⁷ is the CDC’s <1 per million divided by a factor of 2 to reflect the "minimal risk" subgroup language.
Independence note: CDC Yellow Book is the primary US traveler-facing clinical guidance, synthesised from CDC programmatic estimates and the peer-reviewed travel-medicine literature. Shares CDC publisher and authorship overlap with the ACIP MMWR recommendations (Hills et al. co-authored both); Hills et al. 2010 and WHO are the meaningfully independent cross-checks.
Source date: 2024-05-01 · Accessed: 2026-04-11
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- Statistic
ACIP explicitly does NOT recommend JE vaccine for travelers with very low-risk itineraries (shorter-term travel limited to urban areas, travel outside the JE transmission season). The overall incidence of JE among travelers from non-endemic countries to Asia is estimated at <1 case per 1 million travelers. Short-term tourists restricted to major urban areas are at minimal risk — yet JE vaccine is frequently administered to this population, generating financial/inconvenience regret on the inaction side
“"ACIP does not recommend JE vaccine for travelers with very low-risk itineraries (e.g., shorter-term travel limited to urban areas, travel that occurs outside a well-defined JE virus transmission season). ACIP recommends JE vaccine for people moving to a JE-endemic country, longer-term (e.g., ≥1 month) travelers to JE-endemic areas, and frequent travelers to JE-endemic areas. The overall incidence of JE among people from non-endemic countries traveling to Asia is estimated to be <1 case per 1 million travelers. Shorter-term (e.g., <1 month) travelers whose visits are restricted to major urban areas are at minimal risk for JE."”
Calculation notes
CDC Yellow Book — authoritative ACIP guidance defining the boundary between rationally-recommended JE vaccination (long-stay rural Asia) and over-prescription (short-stay urban tourists). The two-dose JE primary series runs ~$300-700 out of pocket in the US; a traveler who pays this for a one-week Bangkok itinerary that ACIP explicitly says does not require the vaccine generates the modal inaction-side regret event for this entry. Used to anchor the ~5-8% baseline financial/inconvenience regret component of the inaction-side estimate. See also [[japanese-encephalitis-travel]] for the absolute risk math.
Source date: 2024-05-01 · Accessed: 2026-05-24
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