People across Scotland will be offered coronavirus antibody tests for the first time as part of a UK-wide programme.
The tests measure the body’s response to a Covid-19 infection and Scots have been urged to take up the offer when booking a PCR swab.
The results will help identify the effectiveness of the vaccine in boosting immunity to the disease.
From Tuesday, anyone over 18-year-olds will be able to opt in to take part when booking a PCR test through NHS Test and Trace.
Up to 8000 people who receive a positive coronavirus result will then be sent two finger prick antibody tests to complete at home and send back to a lab.
Testing positive for antibodies does not mean you are immune to Covid-19 and the same rules still apply – get tested if you have symptoms and self-isolate if positive or are a contact of a positive case and have not received both vaccine doses.
A recent survey found seven in ten Scots successfully followed self-isolation rules, with high compliance among people who tested positive for Covid, their close contacts and international travellers.
The surveillance initiative is the first time antibody tests have been made available to the general public. Until now, only people in specific professions or involved in clinical or research settings have been offered them.
The data will help estimate how many people develop Covid-19 despite having antibodies from their vaccine or from previously catching the virus.
The UK Health Security Agency will work alongside NHS Test and Trace in Scotland, and the rest of the UK to monitor levels of antibodies in positive cases.
Those taking part must take their first antibody test as soon as possible after receiving a positive PCR result.
This is so it takes a measurement before the body has had time to generate a detectable antibody response to the current infection.
The second test is then supposed to be taken 28 days after testing positive for Covid-19 and will measure antibodies generated in response to the infection.
By comparing the two antibody test results, researchers will be able to see how well vaccinated individuals boost their immunity when they are infected and how this might vary with different variants.
It is hoped the surveillance programme will also give an insight into any groups of people who do not develop an immune response.
On Saturday, 4,075,555 people in Scotland had received their first dose of Covid-19 vaccine and 3,541,708 had had their second.
Dr Jenny Harries, chief executive of the UK National Health Security Agency, said: “We are rolling out antibody testing across the UK to gain vital data into the impact of our vaccination programme and on immune responses to different variants of Covid-19.
“This has been made possible thanks to the incredible British public who continue to come forward for testing when they develop symptoms and the millions of people who have had their jabs.
“The best way to protect yourself and those around you is by getting vaccinated. I encourage anyone who has not yet come forward to book their first and second jabs.”