By Philip Blenkinsop
BRUSSELS (Reuters) - The European Union is likely to agree on Friday to let people who are fully vaccinated against coronavirus travel freely within the bloc this summer and also to categorise more EU regions as safer to visit.
The EU is set to introduce by July 1 COVID-19 certificates that will indicate whether a person is vaccinated, has immunity because they were previously infected or has had a recent negative test.
Ambassadors from the EU's 27 countries are expected to approve a modified proposal from the European Commission that people who have been fully vaccinated for 14 days should be free to travel from one EU country to another, EU diplomats said.
Just over a quarter of EU adults are now fully vaccinated.
Individual countries may decide to allow in people who have received just one dose. Restrictions for other travellers should be based on the degree to which the country they are coming from has COVID-19 under control.
As vaccinations accelerate, the bloc will loosen the traffic light colour coding it has used to determine the safety of regions within the EU.
"Green" regions must now have fewer than 25 cases per 100,000 people in 14 days, with below 4% of positive tests. That will rise to 50, or 75 if the positivity rate is less than 1%.
A "red" category would apply where infection rates are up to 500, from a previous maximum of 150.
For travel from a green zone, there should be no restrictions, from orange potential for a test, for red a possible quarantine, with non-essential travel strongly discouraged for "dark red".
Children aged 12 or more could be tested, but would only quarantine if an adult accompanying also had to.
EU member states will also be able to hit an "emergency brake" to bar all travellers from a region showing a spike in more infectious variants of the disease.
Setting the criteria has been a delicate balancing act - with tourism-reliant countries such as Spain and Greece wanting looser restrictions and Germany and other countries to which those tourists will return taking a more cautious approach.
The World Health Organization urged Europeans on Thursday to travel responsibly during summer and said the continent was not out of danger.
The system is designed also to apply to non-EU members of the border-free Schengen zone - Iceland, Liechtenstein, Norway and Switzerland.
(Reporting by Philip Blenkinsop; Editing by Frances Kerry)