The short version
- Yellow fever is the only disease the International Health Regulations designate for proof of vaccination as a condition of entry[1].
- The rule names crews directly: every crew member of a conveyance using a port in a yellow fever risk area shall hold a valid certificate[1].
- A certificate is valid from 10 days after vaccination and, since 11 July 2016, for the life of the person vaccinated[1][2].
- A traveller from a risk area without a valid certificate can be quarantined for up to 6 days in a country where the mosquito vector is present[1].
The IHR rule that names the crew
Most yellow fever guidance is written for tourists. The regulation itself has a paragraph for ships. IHR Annex 7, paragraph 2(g), says every person employed at a point of entry in a yellow fever risk area, and every member of the crew of a conveyance using any such point of entry, shall be in possession of a valid certificate[1].
For an operator, that turns a travel-health question into a crewing question. A vessel calling at a port in a risk area needs every crew member’s certificate in order, not only the ones who plan to go ashore.
| Annex 7 paragraph[1] | What it says | What it means for a vessel |
|---|---|---|
| 1 | Yellow fever is the disease designated for proof of vaccination on entry | The one vaccine certificate a port can demand under the IHR |
| 2(a)(iv) | Certificate valid for life, from 10 days after vaccination | Old certificates count; last-minute ones do not |
| 2(b) | Vaccination may be required of travellers leaving a risk area | Departure ports can check too |
| 2(d) | A valid certificate holder is not treated as suspect | The certificate is what keeps the crew moving |
| 2(g) | Every crew member of a conveyance using a risk-area port holds a valid certificate | All hands, not only shore-leave takers |
| 2(h) | No valid certificate: quarantine until valid, or up to 6 days from last possible exposure | Where the vector is present; whichever comes first |
| 2(i) | A signed medical exemption may allow entry, subject to 2(h) and surveillance | An exemption is not a guaranteed pass |
The 10-day rule that catches crew changes
WHO-approved vaccines protect from 10 days after the dose, and the certificate is valid from the same day[1]. The incubation period used by the regulation is six days[1]. Those two numbers decide whether a crew change goes smoothly.
Worked example
A relief engineer is vaccinated on 1 March and flies out to join on 5 March in a risk-area port. The certificate becomes valid on 11 March[1]. The engineer may be allowed to depart with a not-yet-valid certificate, but on arrival in a country where the vector is present, paragraph 2(h) can apply: quarantine until 11 March or for up to six days from last possible exposure, whichever comes first[1]. Vaccinate at least 10 days before the joining date.
The 2016 change works the other way for long-serving crew. WHA67.13 made validity lifelong, in force for all States Parties from 11 July 2016[2], so a certificate issued years ago is still valid[1].
What makes the certificate itself valid
Annex 6 of the IHR sets the form. A defect on the card can cost the same as no card.
- Approved vaccine. Certificates are valid only if the vaccine used is approved by WHO[3].
- Designated centre. States designate specific yellow fever vaccination centres[1]. In the US, CDC points travelers to designated centers through its clinic locator[5].
- Signature and stamp. A paper certificate must be signed by the supervising clinician and carry the centre’s official stamp; the stamp does not replace the signature[3].
- Language. Completed in English or French, optionally with another language too[3].
- No alterations. Amendments, erasures or blank sections may make it invalid[3].
- One person per card. Certificates are individual and never collective[3].
Getting crew vaccinated in the US, and when a crew member cannot be
| Issue | CDC Yellow Book guidance[5] |
|---|---|
| Vaccine | YF-VAX is the only FDA-licensed yellow fever vaccine in the US; Stamaril was imported during the 2015 to 2021 shortage |
| Boosters | One dose protects most travelers; extra doses for some groups, such as people with HIV at continued risk (every 10 years) |
| Medical waiver | Contraindications section of the ICVP completed, plus a signed letter on letterhead with the centre’s stamp |
| Waiver acceptance | Destination countries may not accept waivers; check before travel |
Under the IHR, a clinician who judges the vaccine contraindicated must give written reasons in English or French, which authorities on arrival should take into account[3]. The regulation still allows those travellers to be quarantined or placed under surveillance[1]. A crew member who cannot be vaccinated is a crewing decision for risk-area trades, not a paperwork detail.
The ship side: vectors and the sanitation certificate
Crews are only half of the yellow fever rules. WHO publishes areas where vector control is recommended, and every conveyance leaving a point of entry in such an area should be disinsected and kept free of vectors[4]. For ships, under IHR Annex 5, vectors found and control measures used are recorded on the Ship Sanitation Control Certificate[4]. A ship can be treated as suspect if it has left an affected area recently enough for mosquitoes aboard to still carry disease[4]. The certificate side is covered in the ship sanitation certificate guide.
A crew yellow fever checklist for risk-area trades
| Check | When | Rule |
|---|---|---|
| Certificate for every crew member, filed with crew documents | Before the voyage | Annex 7, 2(g)[1] |
| Vaccination date at least 10 days before joining | At crew change | Annex 7, 2(a)(iv)[1] |
| Card signed, stamped, complete, in English or French | At sign-on | Annex 6[3] |
| Waivers checked against the destination’s policy | Before routing | CDC Yellow Book[5] |
| Disinsection and SSCC entries after risk-area calls | On departure | Annex 5[4] |
Discovery Health MD builds the crew health side of trading plans for risk-area routes: certificate checks and the joining-date rule through maritime medical consulting, fever and mosquito-borne illness supplies in the chest through ship medical chest management, and lawful pain relief through controlled substances management. Send us your next trading route and we will flag the crew health requirements on it. Also see foreign-flag vessel US port medical requirements and illness and outbreak reporting at US ports.
Common questions
Do ship crew need a yellow fever vaccination certificate?
Every crew member of a conveyance using a port in a yellow fever risk area shall hold a valid certificate under IHR Annex 7, paragraph 2(g)[1].
How long is a yellow fever certificate valid?
For the life of the person vaccinated, starting 10 days after vaccination[1]. Lifelong validity applies to all IHR States Parties from 11 July 2016[2].
Is an old yellow fever certificate still valid?
Yes. The 2016 amendment extended validity for the life of the person vaccinated[1][2], so a certificate is not invalid because it is more than ten years old.
What happens if a seafarer arrives without a valid certificate?
A country where the vector is present may quarantine a traveller from a risk area until the certificate becomes valid, or for up to six days from last possible exposure, whichever comes first[1].
Can a crew member be exempt from yellow fever vaccination?
A signed medical exemption may allow entry, but the traveller can still be quarantined or placed under surveillance[1]. CDC notes some countries do not accept waivers[5].
Where can crew get a yellow fever vaccine in the US?
At a designated yellow fever vaccination centre; CDC lists them through its clinic locator[5]. YF-VAX is the only FDA-licensed vaccine in the US[5].
Does the ship also need anything for yellow fever?
Ships leaving areas where vector control is recommended should be disinsected, with vectors and measures recorded on the Ship Sanitation Control Certificate[4]. See the ship sanitation certificate guide.
