The tsunami effect on infections caused by the Omicron variant around the world is not spreading with the same bullying in intensive care. The impact in the wards where the seriously ill are hospitalized is in fact lower than in the medical area compared to the times of the wave caused by the Delta variant. And according to studies from various countries, the greater percentage of patients intubated or ventilated due to pneumonia would be due to the tail of the Delta which, as now shown by numerous scientific publications, has different and substantially milder symptoms.
Does Delta prevail in intensive care? Data from countries
In Australia, the data extracted from the sequencing of swabs of Covid patients show that 74% of patients in intensive care have contracted Delta and not Omicron. Of these – said Dr. Sonya Bennett, a medical consultant to the government – over 60 percent are not vaccinated and the remaining 40 percent are divided between those who have not completed the cycle with three doses and very elderly people struggling with serious comorbidities. previous ones. Similarly in Ireland, the Health Service Executive said that most people in ICUs have been infected with the Delta variant and are hospitalized due to the effect of delayed disease progression. In Britain, Secretary of Education Nadhim Zahawi argued that Omicron is producing a more promising scheme than the Delta variant in terms of the number of people needing ventilators and the length of time spent in the ICU. “We know that Omicron is less severe and that once the third booster dose is received, the chances of being hospitalized are 90% lower than the Delta variant.” British Health Minister Sajid Javid added yesterday, visiting King’s College Hospital in London and referring to the “latest analyzes” conducted in the United Kingdom. However, the minister added that hospitals still face “a few stormy weeks” due to the number of infections and absences among the staff, with two other health facilities declared just today in a state of alert in England.
The London case: declining hospitalizations
London is perhaps the emblematic example of Omicron’s evolution. The “city” was literally overwhelmed by the new variant which exploded in a very high trend of infections, a flare-up that involved a good portion of the population. At the peak, cases are now down by 20 percent. But the analysis of the admissions is even more indicative. According to reports from the Financial Times, up to mid-January hospital employment was growing by 60 percent compared to the previous week. Then the sharp slowdown with the percentage dropped to 18 percent.
The New York case
In the United States, in areas where Omicron is most prevalent, from New York to Florida to Texas, a smaller percentage of patients are ending up in intensive care units and fewer of them require mechanical ventilation. About 50-65% of admissions to some New York hospitals come for other ailments and then test positive for the virus. “We are seeing an increase in the number of hospitalizations,” Dr. Rahul Sharma, chief emergency physician at NewYork-Presbyterian / Weill Cornell hospital, told The New York Times. “But the severity of the disease looks different from previous waves,” he said. “We are not sending so many patients to ICU, we are not intubating so many patients and, in fact, most of those who are coming to the emergency room who test positive are actually discharged.”
In Italy the Delta queue in hospital?
In Italy we do not have a precise detail (updated to date) of the presence of Omicron but we know that until the period before the Christmas holidays, or before the surge in infections, Delta was still the prevailing variant only to be overtaken with the passing of days. «Much of this mortality peak is the result of infections of twenty days ago – said epidemiologist Perluigi Lopalco – when only the Delta variant was in circulation in Italy. So we must be careful: the wave of Omicron infections that we are recording in these days should not be added to the peak of deaths. Omicron will also hurt but much less than Delta ».
According to the latest weekly report of the Higher Institute of Health, the employment rate in intensive care this week is 15.4% (daily survey by the Ministry of Health as of 06 January) against 12.9% (daily survey by the Ministry of Health as of December 30) of the previous week. The employment rate in medical areas at the national level, on the other hand, rises to 21.6% (daily survey by the Ministry of Health as of 06 January) compared to 17.1% (daily survey by the Ministry of Health as of 30 December).
Omicron infects the throat more than the lungs
Omicron would be more likely to infect the throat than the lungs and therefore, according to scientists, while risking being more infectious it would be less lethal than other mutations of the virus. The Guardian reports it analyzing six recent international studies. The variant «seems more capable of infecting the throat where it would multiply more easily than in cells deep in the lung. These are preliminary results, but the studies point in the same direction ». The hypothesis that Omicron multiplies more in the throat would make it more transmissible, explaining the rapid spread of the virus – writes the British site reporting the studies – which attacks the lungs, more dangerous but less transmissible. According to a study by the University of Liverpool Molecular Virology Research Group, Omicron leads to ‘less severe disease’ in mice, with lower viral loads and less severe pneumonia. The animal model suggests that the disease is less severe than the Delta and the original Wuhan virus. It seems to be eliminated faster and the animals recovered more quickly. ‘ Similar results also come from the Neyts Lab of the University of Leuven in Belgium in Syrian hamsters. And, a further pre-press, presented to Nature by US researchers, confirms the thesis. Omicron – the Center for Research on Viruses of the University of Glasgow points out – would basically be able to evade immunity after two doses but with the booster there is “a partial restoration of immunity”. The Christmas slew of research is based on a University of Hong Kong study last month showing a minor Omicron infection in the lungs and research led by Cambridge University Professor Ravi Gupta that the variant is less in able to enter lung cells. The latest confirmation comes from the University College of London according to which many swabs carried out only in the nose gave negative results, while if repeated even with a sample in the throat they were positive.
The impact of Omicron among young people
For children under the age of 5, the risk of being hospitalized for Covid-19 is one third compared to the period in which the Delta variant was in circulation. This is one of the salient data that emerged from a study coordinated by the Case Western Reserve University of Cleveland (USA) and made available in pre-print on medRxiv. The research analyzed almost 580 thousand diagnoses of Covid-19 made during 2021, comparing the outcomes of the infection in the ‘pre-Omicron’ period with those following the appearance of the new variant. Overall, the study found a halving of the risk of hospitalization, from 3.95% of the circulation period of the Delta variant to 1.75% of that of Omicron. The risk of visiting the emergency room dropped from 15.22% to 4.55%; that of resorting to intensive care from 0.78% to 0.26%; that of needing mechanical ventilation from 0.43% to 0.07%. The data on children are particularly relevant, especially those under the age of 5 who are currently the only age group left uncovered by vaccinations. Also in this case the data are reassuring: the risk of hospitalization is one third in the period of circulation of Omicron compared to that in which the Delta variant was dominant (0.96% against 2.65%); the risk of an emergency room visit went from 21.01% for Delta to 3.89% for Omicron. The same trend was observed in older children and teens. The small number of cases did not allow researchers to draw conclusions on the differences in terms of the need for intensive care and advanced care. Despite this encouraging result, further studies are needed to monitor the long-term consequences of Omicron infection, its propensity for long-Covid development, the impact of the rapid spread of the virus and mutation, and to understand how the vaccines, boosters or previous infections can alter clinical responses, ”the researchers warn.