Holders of yellow fever vaccination certificates will no longer have to renew them after a decade, the World Health Organisation has said.

The certificate issued upon receiving the recommended vaccine will be valid for a lifetime.

Experts on immunisation have found that a single dose of the yellow fever vaccine is sufficient to give sustained immunity and lifelong protection against the disease, making a booster dose unnecessary.

The new regulations will, however, not affect existing certificates of vaccination, as the WHO said there will be no need to change or modify them.

“Nothing needs or should be modified in the certificate. Indeed, under the International Health Regulations (IHR), any changes, deletions, erasures or additions may cause a certificate to be rendered invalid,” the WHO said.

Previously, it was not clear how long the protection from the yellow fever vaccine would last hence travellers were advised to get re-vaccinated every 10 years as per the validity of the certificates set out in the IHR 2005.

Yellow fever is the only disease mentioned in the document for which an International Certificate of Vaccination may be required for entry into a country under the WHO regulations.

The amendments that came into force on July 11, were based on recommendations by the Strategic Advisory Group of Experts on Immunisation, which conducted a scientific review and analysis of evidence on issues related to vaccination against yellow fever in 2014.

“The validity of a certificate of vaccination against yellow fever shall extend for the life of the person vaccinated, beginning 10 days after the date of vaccination,” an updated text of Annex 7 of the IHR reads.

For new certificates, the WHO recommended that countries use words that “clearly and unambiguously indicate that the validity of the certificate is for life of the person vaccinated.”

Yellow fever is an acute viral disease found in tropical and subtropical areas in South America and Africa and is transmitted to people by the bite of an infected mosquito. Its incubation period is six days.

Thirty four countries in Africa and 13 in central and South America  are either endemic for, or have regions that are endemic for, yellow fever. In Africa, an estimated 127,000 people were in 2013 reported to have severe cases of the disease, and 44,000 died.

The new regulations come at a time when the continent has been grappling with outbreaks in Angola Cases were also reported in Kenya (2) and China (11) through unimmunised travellers.