Have you heard of someone who did quick nose exams negative, but tested positive when taking the stick in the mouth? FHI is now studying whether we should run a different test in Norway to find omicrons.
On Wednesday, representatives of the public health authorities of all countries in Europe met. The main topic was rapid tests and omicron. This is the main topic of discussion there now. How effective are rapid tests in detecting the new variant virus? And are we testing correctly?
Joachim Overbow is a physician at the National Institute of Public Health. Attended the European Cooperation Meeting.
– There is great interest in this, both among the authorities in many countries, in the media and the population, he says.
Much of the “ice talk” lies in the many individual stories that FHI has heard as well. People showed negative results when they tested themselves with rapid nasal tests. Then they take a test stick into the throat and test positive.
FHI has also received numerous inquiries from municipal doctors across the country. They are wondering which test method is best. What does it apply to now?
– That’s something to look at. But we’re still not sure if there’s any difference in which test method is most effective at capturing this, Overbow says.
Not made for the neck
There are some small studies that indicate that the amount of virus in the omicron variant is higher in the throat and saliva than in the nose. But it may be due to coincidences.
The NIPH is now studying whether the operating instructions for the rapid tests should be changed, but is awaiting further studies and more documentation.
A major problem is that the tests are not approved for use in the throat. If one has to change its use, it must be professionally well documented.
It takes a bit to recommend a different use than what the test was done for. But national exceptions can be given if we’re sure they have something to do with it, Overbow says.
Other countries are testing in the throat
England uses rapid tests in both the throat and the nose. The new recommendation in Israel is to test yourself three days after close contact with an infected person, because early tests can have false negatives. The test strip should then be used first in the throat and then in the nostril to give a more accurate answer.
Other countries are waiting to see if they can change the way. In Germany, they do their own research. This is also done in Norway.
We do our own research on the rapid tests used here. Then we grow different virus variants and check how well the rapid tests detect different amounts of viruses from the different variants, Overbow says.
Rapid tests are carried out for coronavirus and pick up the so-called protein N. There is little change in this protein between the omicron and the previous varieties. This means that the probability that the tests will perform much worse against Omicron is small.
Therefore, rapid tests are likely to be effective in finding both omicron and delta.
But the question is where the different virus variants become “visible” first. Throat or nose?
– This is something we follow closely. We make sure we bring new knowledge with us and share knowledge within Europe.
vomiting reflex
It may appear that the omicron variant has a slightly different way of entering cells. It thrives best in the airways rather than the lungs. But then you need to see if it has an effect on the amount of virus in your mouth and nose.
If there is a throat test, there are likely to be many who fear the discomfort of vomiting when the stick goes down the throat.
FHI suggests it’s easiest to see yourself in the mirror while scraping carefully with the stick to avoid the vomiting reflex.
And if it turns out that there is a good amount of virus in the saliva, then in this case you can just take the stick along the inside of the cheek.
– That’s what we have to find out. Is it in the nose, saliva, or back of the throat, and how do we do it.
It is uncertain whether we will change usage. We have to wait for better data, Øverbø at FHI says.
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