As countries start to open up borders and ease travel restrictions, many are requiring proof of full vaccination against COVID-19 for entry. This has left some wondering if they need both doses of a two-dose vaccine like Pfizer or Moderna to meet the entry requirements or if receiving just one dose is enough.
What are the current travel requirements for vaccination?
Entry requirements differ depending on the country, but most that currently require proof of vaccination are asking for travelers to have received the full vaccination course recommended by the manufacturer.
For the two-dose mRNA vaccines like Pfizer-BioNTech and Moderna, this means receiving both doses with the proper time interval between them. Some examples of current policies:
- European Union: Accepts travelers 14 days after receiving the second dose of an EMA-approved vaccine like Pfizer or Moderna.
- United States: Foreign nationals must be fully vaccinated with any WHO-authorized vaccine, which for a two-dose vaccine means receiving both doses.
- Thailand: Requires travelers to be fully vaccinated without defining what this means, but presumed to mean both doses of a two-dose vaccine.
A few destinations are accepting travelers with just one dose of a two-dose vaccine, but have additional requirements such as testing:
- Iceland: Accepts travelers who have received one dose of a two-dose vaccine if the second dose was not available to them, provided they test upon arrival.
- Belize: Allows people who have received at least one dose of a two-dose vaccine if they provide proof of the future appointment for the second dose.
Some places are also making exceptions for people who have recovered from COVID-19 and received one dose of a two-dose vaccine. But in general, most countries currently set on requiring vaccination for travel are asking for completion of the full vaccine course.
Why is receiving both vaccine doses important for travel?
There are a few reasons why receiving the full vaccine course with two doses is considered necessary for travel by most countries:
- Greater protection – The efficacy of the mRNA vaccines against COVID-19 infection is much higher after receiving the second dose compared to just receiving one dose. Studies found receiving two doses provided 95% protection, while one dose provided only around 50-80% protection.
- Longer duration of immunity – The immune response and resulting duration of protection is longer after receiving the full two-dose course compared to a single dose.
- Preventing spread – Since the level of protection is higher after two doses, requiring the full course helps prevent vaccinated travelers from getting infected and spreading COVID-19 in the country they are visiting.
- Uniformity – Requiring the full vaccine course creates a uniform standard that is easy for border officers to check rather than try to account for people who may have only received one dose.
Countries want assurance that vaccinated travelers have the best protection possible and are at the least risk of SARS-COV2 infection and transmission. The data shows this is achieved most effectively after receiving both doses of an mRNA vaccine, which is why the full vaccination course is required.
When are you considered “fully vaccinated” with a two-dose vaccine?
With the mRNA vaccines, you are generally considered fully vaccinated 14 days after receiving the second dose of the vaccine. This two week period allows the immune system time to build up protection after the final dose.
So if you receive the second dose of Pfizer’s vaccine 17 days before departure, you would meet the requirements of destinations requiring full vaccination.
The guidelines can differ slightly by country. For example, the CDC defines fully vaccinated as 2 weeks after the second dose, while the UK NHS says you are considered fully vaccinated a week after receiving the second dose. But for travel purposes, two weeks after the final dose is a good rule of thumb.
Can you travel if you only had one vaccine dose?
It is possible to travel after just receiving the first dose of a two-dose COVID vaccine, but your options are much more limited.
There are a small handful of countries like Iceland and Belize that will accept recent recipients of the first dose, but have additional requirements like testing upon arrival. You may also be able to visit a destination that does not require vaccination at all for entry.
However, if you want to have the most travel opportunities and the most seamless entry experience, receiving both doses of the vaccine before traveling internationally is best. Some things to keep in mind if trying to travel after one dose:
- Check entry rules carefully – Requirements can vary between countries and are rapidly evolving.
- Be ready to take COVID tests – Destinations that accept one dose often require proof of a recent negative COVID test.
- Carry your vaccine documentation – Bring your vaccine certificate documenting receipt of your first dose.
- Know you may need to quarantine – Some places require short quarantines upon arrival if not fully vaccinated.
While it may be possible to travel after just one dose, your options are far more plentiful if you wait until after receiving your second dose. As vaccine supply improves worldwide, more people will soon be able to achieve the full protection of both doses.
What if you previously recovered from COVID-19 and had one vaccine dose?
Some countries make exceptions to the two-dose vaccine requirement if you previously recovered from COVID-19 and have received one dose of an mRNA vaccine. In this situation, some destinations consider you to be fully immunized since the one dose acts as a booster to the natural immunity from your recovery.
Countries like Croatia, Cyprus, and Greece have exemption policies in place like this. Proof of recovery plus one dose of an EMA-approved vaccine can allow entry. Other European countries are reportedly considering similar policies.
So in this specific situation, one dose may be enough for entry to some countries if you can provide documentation of your prior COVID-19 infection. But it’s advisable to check the latest entry rules for the destination you plan to visit.
What if you mix and match vaccines?
Some people may receive doses of different COVID vaccines – for example getting AstraZeneca for their first dose but Pfizer for their second. This is referred to as “mixing and matching” vaccines.
Unfortunately, there is not yet a standard policy in place for travel when vaccines are mixed this way. Some countries are accepting any combination of EMA or WHO approved vaccines, but others are requiring the doses to be from the same manufacturer.
If you have received doses of two different vaccines, it’s important to check the requirements of the specific country you plan to visit. Having a complete vaccination certificate clearly documenting which vaccines you received on what dates will be key to provide proof in this situation.
How might requirements change in the future for travel?
As time goes on, travel entry requirements could evolve in a few ways regarding COVID vaccination:
- Accepting first doses – More countries may open up to travelers who have received at least one dose of a two-dose vaccine.
- Mixed dose policies – Clearer global guidance may emerge on mixed vaccine dosages for travel.
- Booster requirements – Boosters may eventually be required once a certain period of time has elapsed since the original full vaccination.
- Vertical vaccine passports – Apps like the EU Digital COVID Certificate could add vaccination records and make verification easier.
- Approved vaccine list – More vaccines like China’s offerings may be added to approved lists for travel purposes.
Entry requirements have been constantly shifting during the pandemic. Proof of full vaccination may give way to other evolving standards for travel in the future. But for now, receiving both doses of a two-dose vaccine remains key for easy international travel.
Conclusion
At this time during the pandemic, having both doses of a two-dose COVID-19 vaccine is required for entry to most international destinations. Completing the full vaccination course provides greater protection and assurance for the countries you are visiting.
A few places are accepting people weeks after their first dose, but policies can vary widely. To open up the most travel opportunities, receiving the full vaccine course with both doses is recommended. However, as the situation evolves, entry policies may change regarding vaccination requirements.
For access to the widest range of destinations and the smoothest entry experience, complete vaccination with both doses is ideal. But be sure to closely monitor the destinations you plan to visit, as requirements are rapidly changing as countries seek the right balance between health security, vaccination proof, and restarting travel flows.
