RESIDENTS and staff at a Skye care home which has already been subject to a Covid-19 outbreak are to be checked again for the virus after a worker who has recovered tested positive for the disease.

Scotland’s chief medical officer, Dr Gregor Smith, urged caution and stressed that somebody who has recovered from Covid-19 who then tests positive does not necessarily mean they have been re-infected with the disease – and it is likely to be a “manifestation of the testing challenges”.

The First Minister has called on those who have recovered from the virus not to be complacent as there is a lack of evidence to suggest that antibodies protect against being infected or for how long immunity may last.

NHS Highland confirmed a member of staff at Home Farm Care Home in Portree has retested positive for Covid-19 but said there are no other cases of confirmed infection in the local community or elsewhere on Skye.

Earlier, MP for Ross, Skye and Lochaber, Ian Blackford, announced on Twitter that he had been told about the incident at Home Farm.

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A spokesperson for NHS Highland said: "Evidence is emerging internationally about Covid-19 and it is now recognised that some people have prolonged positive swab results and others can have intermittent negative and positive results over many weeks.

"An ongoing positive result does not therefore mean they are still infectious or that they pose a risk to others. This is the most likely scenario here.

"Nonetheless, and as a precaution, this person has been advised to remain at home and in isolation."

The spokesperson added: "Their close contacts are being followed up by the contact tracing process and will be given the standard advice regarding isolation and effective hygiene.

"In addition, and as a further precaution, NHS Highland is in the process of retesting all staff and residents of the care home.

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"We will inform all residents, staff and relatives of the results as soon as they are available."

A spokesman for the home said there had been no new Covid-19 cases at Home Farm for 33 days before the result on Sunday.

He said: "We have been assured by public health experts that the positive test returned recently from a Home Farm colleague is likely as a result of the original infection and not due to a reinfection.

"This means that the risk of transmission from this person is very minimal.

"However, we are of course working closely with our local health and care partners and are taking all appropriate steps to respond to this."

He added: "Testing is being made available to everyone who has entered the home recently and will be completed as a matter of urgency.

"Home Farm has had the highest standards of infection control over recent weeks, working in partnership with and overseen by colleagues from the NHS and we are confident we have done all we can to support this home in its recovery."

Dr Smith said it would be “completely inappropriate” to comment on the incident at Home Farm.

He said: “When these cases of supposed re-infection have been examined in detail, one of the things that becomes very apparent in them is that it doesn’t tend to be re-infection that has occurred, it is actually a manifestation of the testing challenges.

“The PCR test, the way that they are deployed, can pick up viral fragments rather than the virus itself. I can’t say with any confidence at all that this is exactly what’s happened with this case.

He added: “I’m not aware of any other cases in Scotland where this has happened – but that is not to say that it hasn’t necessarily happened. This test is very good, it’s very reliable but it’s not fallible.

“Just because the test itself is positive, it does not mean the person has live, viable virus.

Nicola Sturgeon stressed that people who have previously tested positive for Covid-19 and have recovered should still follow the public health advice.

She said: “One of the things we simply do not know about this virus yet, with any certainty, is what level of immunity having it gives you and if it does give you a level of immunity, how long that immunity lasts.

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“Nobody who has had this virus, based on our understanding right now, can assume at all, that they can’t get it again. That doesn’t mean we have evidence of re-infection or that this case means that somebody has been re-infected – but equally, there’s certainty that can happen.”

Dr Smith added: “You cannot say that having had the infection means you won’t get it again – we cannot say that having antibodies will protect you in future.

We know that people develop antibodies after the infection, but the significance of that is still to be reviewed through the research and the evidence we continue to develop.”