How long does it take for omicron symptoms to appear? And why does it spread faster than other strains?
The Omicron mutant raises concerns around the world, and data so far has shown that it spreads faster than previous strains, which experts are trying to determine its causes despite the difficulty of the task.
in a report Posted by The American magazine “The Atlantic”, writer Catherine Ji Wu says that the first copy of the emerging corona virus was relatively slow, as the virus remains inside the body 5 or 6 days before symptoms appear, but the incubation period of mutated strains is shorter than that.
According to some estimates, the incubation period for the alpha mutant is about 5 days, and the delta mutant is 4 days, but the incubation period for the Omicron may not exceed 3 days.
Experts believe that the incubation period plays a crucial role in the spread of mutated strains of the Corona virus, as the shorter the incubation period, the more contagious the person becomes, and the faster the disease spreads. And Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Center for Health Security, stresses that the short incubation period “makes the virus much more difficult to control.”
This is what the numbers prove on the ground. In less than a month, Omicron has spread to dozens of countries, and infection rates have reached record levels. Because the battle against Omicron is still in its infancy, it does not seem easy to collect data on the incubation period, or know the ways the virus affects the cells of the body, but there are many alarming indicators, according to the writer.
“If it’s an incubation period or a micron shorter than the others, it will create chaos in our detection and handling,” says Umay Garner, a clinical microbiologist at the University of California, Los Angeles.
Since the World Health Organization classified Omicron as a worrying mutant at the end of November, researchers have worked to track its cases in schools, child care centers, hotels, universities, weddings and cafes, and one of the research discovered that nearly 80 people were infected at once at a party in a restaurant in the capital. Norwegian Oslo.
In a research paper on that incident, experts noted that symptoms began to appear quickly within about 3 days, and the most worrying thing is that most of those who were infected at the party confirmed that they had received all doses of the vaccine, and that they had obtained a negative test result during the two days preceding the party.
The results of this study are consistent with some research conducted in South Africa, one of the first countries to detect and report the spread of the omicron mutant. Research has revealed that shorter incubation periods often lead to more infections in less time, and it becomes more difficult to break cycles of infection.
omicron diffusion velocity
Ajay Sethi, an epidemiologist at the University of Wisconsin, stresses that more data is still needed on Omicron before determining the incubation period, but the current findings are logical – in his opinion – given the doubling of infection rates within two to three days. In most of the countries where Omicron has spread.
However, experts believe that determining the incubation period is difficult, because it requires tracking large foci of infection, and taking into account many data, such as vaccination, health conditions, infection history, age, viral load and how the infection is transmitted.
The omicron’s spike protein has more than 30 mutations, which help it stick to cells more firmly and hide inside them more efficiently.
Two recent studies, not yet published in any scientific journal, support these hypotheses about the speed of omicron’s spread. The first study, conducted by a team from Harvard University, showed that a harmless virus similar to Omicron, during in vitro experiments, was able to easily penetrate human cells. Another study from the University of Hong Kong found that omicron multiplied dozens of times faster than delta in tissues extracted from the upper respiratory tract.
If these results are proven, says Lisa Gralinsky, a virologist at North Carolina State University in Chapel Hill, “we could go a long way to explaining the rapid transmission” of the omicron mutant.
A number of experts believe that unvaccinated people are most at risk, but the new mutation will also affect those who have received the vaccination or who were previously infected with corona.
Ryan McNamara, a virologist at Harvard Medical School, says that the immune system of a person who has been vaccinated or who has previously been infected with the virus, is able to resist the new mutant, by producing more antibodies and releasing an army of T cells capable of suppressing the virus before reaching the virus. The danger stage, but these immune defenses take a few days to appear and may be delayed in recognizing and dealing with the virus during the early stages, meaning that the faster the Ommicron, the less the ability of the immune system to resist it.
Effectiveness of tests
The short incubation period means that there is less time to detect the infection before it spreads, meaning that people who think they have Omicron should get tested as soon as possible to limit its spread.
Melissa Miller, a clinical microbiologist at North Carolina State University, explains that this means that the results of tests for Omicron infection will be shorter-lived compared to previous strains, because the tests provide a quick glimpse into the past and do not predict the future, meaning that the fast-replicating virus may appear after a few hours. of the negative test.
This means that PCR tests – which have been the gold standard for diagnosing cases of corona since the outbreak of the epidemic – will not be effective enough in the case of Omicron. Currently, rapid antigen tests are seen as the best solution to deal with the new situation, as, despite their shortcomings, they provide results faster than what happens in the body.
But some experts believe that these tests will not be effective enough to detect the omicron mutant, especially since they have a lower ability than PCR tests to pick up the virus if it is present at very low levels.
The writer concludes that, in light of the fears of the spread of the Omicron mutated and the difficulty of dealing with it, there is an urgent need to redouble preventive measures such as vaccination and ventilation, and to reduce travel and social contact, because these viruses do not move on their own, but are transmitted by humans.