PROPERTY SEARCH
PROPERTY SEARCH
ARCHIVED - Why antigen tests in Spain can produce a false negative
The experts explain that rapid antigen tests are effective when the patient is most infectious
The Christmas festivities are almost upon us and in anticipation of family gatherings, work dos and parties, many people throughout Spain are turning to over-the-counter antigen tests to ensure they are as healthy as possible, so much so that pharmacies in the Region of Murcia have begun to run out of stock.
However, the experts have now warned that incubation period of the Omicron variant, which has proven to be extremely transmissible, is very different from previous strains, so that antigen tests may be even more unreliable.
Virus experts in Spain have advised anyone who believes they may have contracted Omicron to obtain a PCR test, which are much more sensitive and reliable. A professor from the University of Seville explained that, with antigen tests, the results can vary over a matter of hours depending on the person’s viral load, so that the over-the-counter test could read negative in the morning and another could be positive by that same afternoon.
SEE ALSO: The best way to do a rapid test
This very point was proven by a UK-based epidemiologist who took to social media to show the results of four separate antigen tests he carried out on himself over a 24 hour period. Three were negative; the fourth showed that he had coronavirus.
A demo of how fast you can turn positive:
— Billy Quilty (@BQuilty) December 16, 2021
Yesterday morning, yesterday lunchtime, yesterday evening, this morning.
Do LFTs *just* before meeting up. pic.twitter.com/3zM2rDkoa7
Antigen tests DO work
A professor at Harvard University, Michael Mina, was quick to point out that antigen tests are a useful tool, but that they may produce a false negative in people who have been vaccinated.
He explained that, if, for example, a person was infected on January 1, on day three they would begin to feel symptoms but not test positive with an antigen test until day five. This is because the viral load would be strongest between day 5 and 9, the days when the patient is the most contagious.
In contrast, the more sensitive PCR is capable of detecting lower viral loads, and would register a positive even when the person was not infectious.
“Rapid antigen tests are positive when it matters most: when people are infectious,” concluded Mr Mina.
IMPORTANT:
— Michael Mina (@michaelmina_lab) December 18, 2021
RAPID TESTS DO WORK WITH OMICRON
"But why are some people staying negative in the first days they have symptoms??"
This is expected. Symptoms don't = contagious virus
This is literally a reflection of the fact that vaccines are doing their job!
PLEASE READ pic.twitter.com/YBJvNovQXL
Image: Archive
Read more about Coronavirus:
OR
Sign up for the Spanish News Today Editors Roundup Weekly Bulletin to get a comprehensive email with all the week’s news for Spain, Murcia, Alicante and Andalucía.
Get a sneak peek – here are a few of our recent Subscription Bulletins:
50% Discount Special Offer subscription:
24.95€ for 48 Editor’s Weekly News Roundup bulletins!
Please CLICK THE BUTTON to subscribe.
Contact Spanish News Today: Editorial 966 260 896 /
Office 968 018 268
