The World Health Organization recently updated its recommendations for yellow fever immunization. Zambia was placed on a list of countries where there is low, or minimal risk of yellow fever. Most travelers do not need yellow fever immunization for their own protection. WHO recommends that "proof of yellow fever vaccination should not be required if traveling from one of these countries to another country with a vaccination entry requirement (unless that country requires proof of yellow fever vaccination from all arriving travelers."
However, any country can do as it pleases in terms of its own law or policy. WHO can only make recommendations. A number of countries, including South Africa, have chosen to leave Zambia on their lists.
Here is South Africa's official YF policy.
Bottom line is:
Effective October 1:
YF cert required of everyone older than 1 year who is arriving from, or has transited through, any country determined by WHO to be at risk of yellow fever transmission. This includes countries considered to have low risk (SaoTome and Principe, Somalia, United Republic of Tanzania and Zambia).
Transiting means any time spent in a layover, even if it was just an hour in an airport.
If you don't have a certificate, you will be refused entry.
If you have a certificate, but it is not yet valid, because it hasn't been 10 days since you got the shot, you will be quarantined until the cert. is valid or until 6 days have passed.
If you have a medical exemption, you will be
- allowed entry
- required to report any fever or other symptoms to the health authorities
- be placed under surveillance.