Yellow fever

What is Yellow fever?

Yellow fever is a mosquito-borne acute viral haemorrhagic disease which is caused by the yellow fever virus. Vaccination is a key preventive measure against yellow fever.

What are the symptoms of Yellow fever?

The majority of the infected persons are asymptomatic or have only mild illness. Clinical signs and symptoms of yellow fever includes:

• Fever

• Headache

• Myalgia

• Nausea

• Vomiting

Symptoms usually develop within 3 to 6 days after the mosquito bite. Recovery from yellow fever infection results in lifelong immunity.

What are the potential complications of Yellow fever?

A more severe form of the disease is characterised by high fever, jaundice, bleeding, and eventually shock and failure of multiple organs. A small proportion of patients who contract the virus develop severe symptoms and approximately half of those with severe disease die within 7 to 10 days.

How does Yellow fever spread?

Yellow fever is transmitted through the bite of an infected Aedes mosquito. Although there are no reported cases in Singapore, any importation of the disease could result in the disease taking root here due to the presences of the Aedes mosquito vector.

The incubation period is about 3 to 6 days.

How do I prevent Yellow fever?

Vaccination is a key preventive measure against yellow fever.

Travel to affected countries

To fully protect yourself against yellow fever during your travels, we advise travellers to receive the yellow fever vaccination 10 days before your travels. A single dose of the yellow fever vaccine confers lifelong protection against the disease 10 days after vaccination. A booster dose is not required.

Yellow fever vaccination is available at more than 100 GP clinics in Singapore, as well as travel health clinics at public and private hospitals. Please ask your doctor to review your suitability for the yellow fever vaccine.

For persons who are ineligible to receive the vaccination (e.g. children aged 1 year old and below and individuals with contraindications), taking precautions against mosquito-bites can provide some protection. These include:

• Stay in rooms which are well-screened or air-conditioned;

• Wear long, covered clothings that cover most of your body

• Apply an effective insect repellent, such as those containing DEET (N,N-diethyl-m-toluamide), Picaridin or IR3535 as the active ingredient regularly.

Persons who are ineligible to receive the vaccination are still liable to be quarantined under the Infectious Disease Act, for 6 days from date of departure from countries with risk of yellow fever transmission, given the public health risks.

Yellow fever vaccination requirement to enter Singapore

Singapore is free from yellow fever. To protect against the risk of importation and transmission of yellow fever in Singapore, all travellers, including Singapore residents, with travel history to countries with risk of yellow fever transmission (regardless of area, city or region) in the 6 days prior to arrival in Singapore are required to have a valid yellow fever vaccination certificate and present it to the Immigration and Checkpoints Authority (ICA) officer at the immigration counter upon arrival to Singapore. The certificate is also required for travellers with more than 12 hours airport transit in these countries.

The International Certificate of Vaccination for yellow fever becomes valid 10 days after vaccination* and the validity lasts for the life of the person vaccinated.

*If the yellow fever vaccine was administered on 1 January 2021, the vaccination certificate is considered valid from 11 January 2021 onwards.

Travellers without a valid yellow fever vaccination certificate (e.g. unvaccinated individuals, including those who are ineligible to receive the vaccination, and travellers whose certificate has yet to become valid), are liable to be quarantined under the Infectious Disease Act, for 6 days from date of departure from countries with risk of yellow fever transmission. The period of quarantine is to cover the incubation period for yellow fever (i.e. 6 days).

For travellers whose vaccination certificate has yet to become valid upon arrival in Singapore, they will still be required to complete the quarantine even if the vaccination certificate subsequently becomes valid during quarantine. This is because they would not have been fully protected against yellow fever during their time in affected countries and may already be infected and incubating the infection. Quarantine must be served at designated vector-free government quarantine facility. Non-residents who refuse quarantine will be denied entry into Singapore.

How is Yellow fever treated?

There is no specific treatment for yellow fever. Treatment is mainly supportive.