International Attendees

Updated April 12, 2022.

Please note: All participants at the in-person conference—presenters, attendees, exhibitors, staff members, guests, and vendors—will be required to be fully vaccinated and boosted, if eligible, and will be required to present negative test results from within 72 hours of their arrival to the meeting. You will be asked for proof of vaccination and a negative test. Proof of vaccination is your vaccination card (photo is acceptable) from the healthcare provider. Further policies can be found on the Conference Policies page. Before booking your travel to the US, please visit the US State Department’s website for the most up-to-date information.

Helpful Links

FAQs on COVID-19 vaccination and testing requirements

Requirements for air travelers to the US

Travelers prohibited from entering the US

US Visa application procedures and estimated wait times

Visa Waiver Program

National Academies International Visitors Office

Electronic System for Travel Authorization

Requirements for international travel to the United States

As of November 8, 2021, the United States has reopened to fully vaccinated international travelers. GSA advises scientists traveling to the US to stay up-to-date on the latest international travel requirements.

Vaccination requirements 
Effective November 8, 2021, all non-immigrant, non-citizen air travelers (with limited exceptions) are required to be fully vaccinated and to provide proof of vaccination prior to boarding a flight to the United States.

COVID-19 testing requirements

Air travelers aged two and older, regardless of nationality or vaccination status, are required to show documentation of a negative viral test result taken within one day before boarding their flight to the United States.

Visa applications

We advise scientists traveling to the US to apply for a visa as early as possible; at least six months before the visa is needed. Please check with your local US consulate or embassy to find out the earliest that you may apply for a visa.

All visitors traveling to the US (including from Visa Waiver Program countries) must register their details online at least three days in advance of travel. The Department of Homeland Security (DHS) Electronic System for Travel Authorization (ESTA) is a free, automated system used to determine the eligibility of visitors to travel to the United States. It collects the same information as the paper I-94W form you usually complete when traveling to the United States. ESTA applications may be submitted at any time prior to travel, provided it is three days in advance of travel. An ESTA authorization generally will be valid for up to two years. DHS recommends that travelers submit an ESTA application as soon as they begin travel plans.

If you are NOT eligible to travel under the Visa Waiver Program you will need to:

• Apply for a visa at least six months in advance.
• Provide your entire trip itinerary, including travel to any countries other than the United States, at the time of visa application.
• If your travel plans depend on early approval of the visa application, you must specify this at the time of the application.
• Provide proof of scientific status. For example, proof that you submitted an abstract for the meeting. Do not wait until you receive notification that your abstract has been accepted before applying for a visa. It is very rare that an abstract is denied.
• Provide a link to the meeting website and a copy of your letter of invitation.
• Provide evidence that you are intending to return to your country of residence. This includes such things as:
  • family ties in current country of residence;
  • property ownership;
  • bank account;
  • employment contract or statement from employer showing that position will continue after the dates of the meeting.
• Visa requirements vary by passport-issuing country and citizenship (not merely residency).

If you are experiencing significant visa delays, we encourage you to fill out the National Academies visa survey. This allows them to bring your case to the attention of the US Department of State and to track trends in visa issues among the scientific community.

Visa questions should be directed to the National Academies International Visitors Office: visas@nas.edu.

Letter of Invitation

Customized letters of invitation will be available to those who have registered for the meeting or submitted an abstract. A link to request your letter of invitation will be provided in your confirmation. For security purposes, letters of invitation can only be sent to individuals that have registered or submitted an abstract for the meeting.