Folks in England have been cautioned in opposition to utilizing coronavirus antibody assessments being offered by some retailers.
NHS England’s medical director Prof Stephen Powis mentioned consultants had been “evaluating” antibody assessments, which present if somebody has already had the virus.
Such assessments should not but obtainable by the NHS, however some are being offered commercially.
“I might warning in opposition to utilizing any assessments… with out realizing fairly how good these assessments are,” mentioned Prof Powis.
At present, the coronavirus assessments obtainable to all adults and kids aged over 5 are swab tests – taking a swab up the nostril or from the again of the throat. These assessments let you know when you at the moment have Covid-19.
A second kind of check – the antibody check – is a blood check that appears for antibodies within the blood to see whether or not an individual has had the virus.
Well being officers in England have already approved an antibody test. There is no such thing as a date for when it will likely be rolled out, however Well being Secretary Matt Hancock mentioned earlier this week the federal government was in “the closing levels of business negotiations”.
On Wednesday, Superdrug grew to become the most recent enterprise – and first excessive avenue retailer – to supply the antibody check. The package prices £69 and patrons must take a blood pattern at residence, which is distributed off to a lab for testing.
Questions over immunity
Talking on the No 10 each day briefing on Wednesday, Prof Powis mentioned: “Public Well being England have been evaluating the brand new antibody assessments, the industrial assessments which can be changing into obtainable.”
However he added: “I might warning in opposition to utilizing any assessments that may be made obtainable with out realizing fairly how good these assessments are… I might warning individuals in opposition to being tempted to have these assessments.”
Setting out a few of the uncertainties across the industrial assessments, Prof Powis mentioned: “After you have the virus, the physique’s immune system develops antibodies in opposition to it and it is these antibodies which can be detected usually various weeks after you’ve got had the virus.
“What we do not completely know in the meanwhile is whether or not having antibodies and having the antibodies which can be examined in these assessments signifies that you will not get the virus once more.
“So I would not need individuals to assume simply since you check constructive for the antibody that it essentially signifies that you are able to do one thing totally different when it comes to social distancing, in the way in which you behave.
“As a result of till we’re completely positive in regards to the relationship between the constructive antibody check and immunity, I believe we as scientists would say we have to tread cautiously going additional ahead.”
Superdrug mentioned it was “assured” within the accuracy and reliability of the check, which it mentioned has a sensitivity of 97.5%. Meaning it’s going to detect constructive antibodies 97.5% of the time, so there’s a probability a damaging outcome could also be flawed.
There’s a variation within the accuracy of assessments. A test developed by scientists in Scotland and Switzerland had a 99.8% accuracy charge for giving a constructive outcome.
Dr Colin Butler, from the College of Lincoln, mentioned the industrial assessments “ought to give indication” of whether or not a person has been contaminated with Covid-19.
However he added: “While this can be a sign of useful immunity, affirmation of that is awaited from giant scale research presently underneath approach. Till it’s, people mustn’t assume they’re absolutely proof against additional an infection.”
The World Health Organization says there is no such thing as a proof individuals who have recovered from Covid-19 and have antibodies are shielded from being contaminated once more.
The brand new coronavirus, referred to as Sars-CoV-2, has not been round lengthy sufficient to know the way lengthy immunity lasts, however there are six different human coronaviruses that may give a clue.
4 produce the signs of the frequent chilly and immunity is short-lived. In two coronaviruses – those that trigger Extreme Acute Respiratory Syndrome (Sars) and Center East Respiratory Syndrome (Mers) antibodies have been detected just a few years later.