35 years. Rapid immunization of population at risk is the most effective control strategy.* International certificate of vaccination - Valid 10 days after date of vaccination and extends up to 10 years. WHO recommends re-vaccination after 10 years.* All travellers (including infants) exposed to risk of yellow fever or passing through endemic zones of yellow fever must poses a valid International certificate of vaccination.* Quarantine - A traveller without a valid international certificate of vaccination' is placed on quarantine in a mosquito proof ward for 6 days.">