“I have a cold and a bit of a headache, but I have a swab and I’m negative.” And here is the confirmation for dinner with friends the next day. Or a visit to the parents’ home. Then comes the fever, sneezing becomes more frequent, but the test is still negative. “It will be air conditioning,” she thinks. Three days later, to be sure, another test is tried: positive. What about the symptoms? They begin to subside. “I’m already better, now I have to stay at home but I have almost nothing.” But the involuntary omelette is done. The contagion runs and the bulletin rears up. Here is the new wave: it is the Omicron 5 effect. The new variant is really new, in the symptoms that trigger less serious disease especially in vaccinated people who – according to the report of the Higher Institute of Health – have a much lower percentage of not immunized to become seriously ill and die. But Omicron 5 is especially different in triggering the infection. Its ability to infect, superior to all the previous variants (even the sisters BA.1 and BA.2), moves with anomalous timing. Even from case to case. And it is this unpredictability that makes dissemination less manageable.
Omicron 5, the anomalous cases
There are many cases that have been emerging in recent weeks. “My partner is positive, but I am negative: maybe I have iron antibodies.” Days pass and the test shows no worrying signs. “Maybe I escaped it, but I’m cold.” But no, after some time the incubation has run its course and the line of positivity appears, suddenly when the risk seemed to have escaped. In the meantime, the little girl born a few months ago, who could not get the vaccine, has had a high fever for days. It’s still. A boy arrives at the soccer match with friends, finally negative after a week spent at home: «I had a fever, negative test. Then it passed and the next day the swab was positive: I stayed at home waiting to get negative without any symptoms ». A few days later the new surprise: his daughter is positive. “How is this possible?” She asks herself. “When did I actually get her?” Mysteries of Omicron 5.
The case of negative swabs
The tests are not and have never been perfect, but after the rise of Omicron the problem of delayed positivity has gained some prominence. In recent months, many people have had negative tests – three, four, even five or more consecutive days – at the start of their course of Covid symptoms. “I think it’s become more common,” Amesh Adalja, an infectious disease physician at the Johns Hopkins Center for Health Security, told The Atlantic. No one can yet say how common these first negatives are or who is most at risk. But if SARS-CoV-2 is rewriting the early infection playbook, “that makes it really scary,” says Susan Butler-Wu, a clinical microbiologist at USC’s Keck School of Medicine. “You can get a negative test and you may not actually be.” Misleading negative tests could actually accelerate the spread of the virus; delaying the measures established in the event of a positive result. New timelines that also clash with the current Covid dogma: take a swab as soon as you feel bad. The few days around the onset of symptoms should be when the virus inside you is most detectable and transmissible; an entire test and insulation building was built based on those foundations.
Why are tampons negative with symptoms?
Experts aren’t sure why delayed positivity occurs. Population immunity, viral mutations, and human behavior are likely to all play a role. Regardless, the virus “definitely behaves differently from a symptom standpoint,” says Emily Martin, an infectious disease epidemiologist at the University of Michigan. It is worth paying attention. The onset of symptoms has always been divided into two phases: is it Covid or not? If SARS-CoV-2 is reshaping its moves, we must too, or we risk losing our balance. Right now, experts are operating in a vacuum of evidence: “I don’t even know any data that systematically evaluates it,” says Yonatan Grad, who is studying the viral dynamics of SARS-CoV-2 at Harvard’s School of Public Health. . But several phenomena could conceivably confuse the test timeline.
How serious is the disease caused by Omicron 5?
On 5 July in Italy, 13.5% of patients admitted to intensive care were positive for Sars-CoV-2, while 5.1% had severe symptoms attributable to Covid-19. The photograph comes from data from the Siaarti network (Italian Society of Anesthesia, Analgesia, Intensive Care and Intensive Care) processed by the ISS. “There is an increase in congestion in hospital facilities, although fortunately the occupancy rate of intensive care posts is still relatively low. Given the high speed of viral circulation, the fact that in the summer there are always great events and large gatherings of people, it is good to maintain prudent behavior and above all to use a mask in case of large gatherings “. Said the Prevention Director of the Ministry of Health, Gianni Rezza, commenting on the data of the weekly monitoring Iss-Ministry of Health.
So how serious is the disease caused by Omicron 5? A recent preprint publication (which has not been peer-reviewed so far) by a Japanese research team found that in cell culture laboratory experiments, BA.4 / 5 was able to replicate more efficiently in the lungs. with respect to BA.2. In the hamster experiments, it developed into a more serious disease. However, data from South Africa and the UK also found that there was no significant increase in serious illness and death during their recent Omicron 5 spate. This is likely due to the high rates of immunity from previous infections and vaccination.
The new Moderna bivalent booster
New clinical data on Moderna’s bivalent anti-Omicron (BA.1) booster candidate shows that a dose of 50 micrograms elicits significantly higher antibody responses against Omicron 4 and 5 subvariants, responsible for the current surges in several countries and, according to forecasts , in the process of becoming dominant in the EU. This is what the US company reports in a note, which today released new data on the mRNA-1273.214 booster candidate. The results in question were recorded one month after administration of the booster candidate in previously vaccinated and first booster trial participants. Responses in terms of neutralizing antibodies against BA.4 and BA.5 were superior to the currently authorized booster, explains Moderna, regardless of previous infection or age. In detail, among participants without prior infection, bivalent mRNA-1273.214 resulted in significantly higher neutralizing antibody titers against BA.4 / 5 compared to the currently authorized booster, with a geometric mean ratio of 1.69. One month after the recall, the neutralizing BA.4 / 5 titers were 776 for mRNA-1273.214 and 458 for the currently authorized booster. The variation in the geometric mean (Gmfr) of the BA.4 / 5 antibody titers compared to the pre-booster levels was 6.3 times in those who received the bivalent anti-Omicron candidate booster 1 and 3.5 times for those who received booster with the currently authorized vaccine. The results were consistent across subgroups, including those over 65. Full data was submitted for peer-reviewed publication and shared with regulatory authorities.
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