Singapore will begin implementing differentiated rules for social gatherings based on vaccination status tomorrow.

This is part of the country's four-step reopening process, with the eventual goal of becoming a Covid-resilient nation.

But how long will such differentiated rules last, and when will vaccinated and unvaccinated people be able to meet on equal terms?

Here are some questions answered:

Q: If I am not vaccinated, can I eat in a restaurant after I test negative for Covid-19?

A: Yes, you can.

Under the new rules, fully vaccinated people can dine at restaurants and other eateries in groups of up to five.

A person is considered fully vaccinated two weeks after he or she has received the full regimen of Pfizer-BioNTech/Comirnaty, Moderna, or any vaccines listed on the World Health Organisation's Emergency Use Listing.

If you are unvaccinated but have a valid negative pre-event test result, you can still be in such a group. However, you must pay for the test.

If you do not want to take the test, you will be able to eat out only at hawker centres or coffee shops, which are open to all regardless of vaccination status. But you can do so only alone or with one other person - even if all are vaccinated.

Qv Where can I get a pre-event test and how much does it cost? How long do the results remain valid?

A: The list of clinics offering antigen rapid tests is available on the Ministry of Health's website, along with the costs of getting tested at each clinic. These fees generally range from $30 to $100.

The result of such a test is valid for up to 24 hours. For example, if you are attending a wedding lunch that is expected to end at 3pm, you must have taken the test no earlier than 3pm the day before.

Q: What kind of proof of vaccination do I need to show? What if I were vaccinated overseas?

A: You will need to show just your vaccination status displayed in the TraceTogether or HealthHub mobile apps.

People who do not have these apps can show hard-copy proof of vaccination if they were vaccinated in Singapore.

However, hard copies of overseas vaccination certificates will not be accepted.

"This is because it will be difficult for individual establishments to verify the authenticity of these certificates which are issued in different formats and languages," the Health Ministry said.

Q: How long will it be before the vaccinated and unvaccinated can meet on equal terms?

A: This will depend on how long it takes for the threat posed by the coronavirus to recede - not just within Singapore but on a global scale, say infectious disease experts.

Professor Teo Yik Ying, dean of the National University of Singapore's Saw Swee Hock School of Public Health, said that differentiation by vaccination status is likely to continue for at least the next 12 to 18 months.

This is to continue protecting unvaccinated people while allowing the rest to progressively return to normalcy in their everyday lives.

Professor Paul Tambyah, president of the Asia Pacific Society of Clinical Microbiology and Infection, said Singapore is such an open country that setting a proportion of its own population as a target for vaccination and reopening is not possible. "When Covid-19 is no longer a global health threat, there will be no logical reason for mandates," he said.

But he also pointed out that children who have not received the measles and diphtheria vaccines are still treated differently in the education system, even though both diseases have been around for decades. These vaccines are compulsory for children entering primary school. Those who cannot get vaccinated for medical reasons are given exemptions.

Clarification note: The answer to the question - What kind of proof of vaccination do I need to show? What if I were vaccinated overseas? - has been updated to reflect new information from the Health Ministry.