What more do we know regarding symptoms related to variant Omicron ?
Symptoms remain similar to variants previous ones, the most common being sore throat, cough, nasal congestion, headache, general muscle pain and severe fatigue.
Loss of smell and taste no longer seems as common as in previous waves, a few studies now note. “We can no longer trust this symptom, or other more serious advanced during the pandemic,” notes virologist Benoit Barbeau.
In France, public health published last friday observations which abound in this direction. Loss of smell or taste was only reported in 9% of the cases investigated.
Symptoms of Omicron might also appear more quickly, since a shorter incubation time seems to be confirmed.
Can getting Omicron sound like a cold?
Yes, but not necessarily, replies Mr. Barbeau, professor at UQAM. “The message has been adjusted and we recalled during the holiday season that it might be relatively light and resemble a cold. “
You don’t have to ‘add up’ the symptoms to decide to isolate yourself, he insists: “The watchword is simple: it doesn’t matter which of the symptoms on the list, the runny nose, the itchy throat, a slight cough, even if it seems trivial to you, assume that you may be infected with the virus. “
Even though you might think it’s just a mild cold, it might be Omicron. There is also the possibility of transmitting the virus, even without symptoms, ”recalls David Juncker, professor of biomedical engineering at McGill University.
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Are rapid antigenic tests reliable in detecting Omicron?
“Yes” is Mr Juncker’s short answer. “They might be less sensitive, but the difference is not yet significant,” he adds.
On December 28, the United States Medicines Agency (FDA) warned that antigenic tests did indeed detect the Omicron variant, but “that they might have reduced sensitivity ».
This does not mean to do without rapid tests: “Even if they were found to be less sensitive to Omicron, they detect positive people in their infectious phase, which is therefore contagious. This is what is essential to cut the chain of infection, ”insists this specialist.
Antigenic tests react to the presence of antigens on the surface of the virus, while PCR tests detect any genetic material of the virus. However, Health Canada requires that the detection rates of nationally approved rapid tests be almost equivalent to that of PCR tests.
However, PCR tests detect positive cases for “weeks” following the initial infection, which makes Juncker say that the “bar is too high” for the approval of rapid tests. “Let us compare apples with apples, therefore antigenic tests with others, not with PCRs”, he illustrates. It is the “test culture” and “mistrust” that must now be changed, he believes, by promoting repetitive testing with rapid results, when the viral load is likely to be high.
I tested negative and then tested positive. What should I trust?
On the positive test, since “false positives” are very rare.
A “false negative” only indicates that the viral load may not have been high enough at the time of the test. “If you are in the incubation phase of the virus, you have just had contact with an infected person, you can be negative”, explains the professor at McGill University.
“If you were asymptomatic or mild symptomatic, there is a chance that you are negative”, abounds Benoit Barbeau. The ideal would therefore be to repeat the rapid test, if there was no shortage, say the two experts.
Should I take the sample from my throat, in addition to the nose for my rapid test?
Under the hashtag #SwabYourThroat (Prélève dans ta gorge in French), several Internet users have started posting positive rapid tests, claiming to have taken a sample from their throat rather than their nose.
A recent study – published but not yet peer reviewed – argues that samples taken from the throat rather than the nose increase the performance of some PCR tests.
The idea is not far-fetched, since it is possible that more viral particles are found in the throat than in the nose, recognizes Benoit Barbeau.
However, he urges great caution, since the tests were not necessarily designed to be performed in this way. “In the throat, other compounds might interfere with the results. We must therefore wait to have clear directives from the companies developing these tests or from the government authorities, ”he said.
David Juncker diverges on this point: “The test was not approved in this context, but if we wait to be sure that it is the right thing to do, we deprive ourselves of a better detection now, ”he argues.
He believes the recommendations should even change quickly: “If I think I have symptoms, I sample my throat and nose with the same swab. And I repeat a day later, ”he explains.
In Ontario, the Ministry of Health indicated in december that some companies’ tests, including Panbio and BD Veritor, might admit samples from both the throat and the nose.
There is no indication that the rapid tests distributed in Quebec, most of the BTNX brand, work with this type of sample. The method is also not approved by Health Canada at this time.
“If we really wanted to be confident, we would do a test every day. But that’s impossible at the moment, ”laments Mr. Juncker.
If I have been infected, should I still receive my third dose?
At this time, the scientific data cannot determine whether infection with Omicron offers at least equivalent protection with the booster dose. A document from the Institut de santé publique du Québec (INSPQ) dated December 16, note that a booster dose in a person “who has already received 2 doses of vaccine and had a confirmed infection is of little use”.
Therefore, administration of the booster dose is not yet considered “necessary” for these individuals, but might be injected on demand following a minimum interval of eight weeks.
