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The median age of onset is 36 years, and lung toxicity is decreasing
As the mutant Plant, Olmiqueron, swept the world, South Africa announced the "lifting of curfews" and other epidemic prevention measures.
South African scientists were the first in the world to report and discover the Discovery of Omi kerong. Since then, the strain has spread widely, causing new high infections in countries such as Britain, France and the United States, and tightening public health measures in many countries.
But today, "all indicators suggest that South Africa has passed the peak of wave 4 at the national level." Recently, the South African government issued a statement quoting data from the country's Ministry of Health that except for the Western Cape and the Eastern Cape, the number of new cases and hospitalizations in other provinces has declined. At the same time, wave 4 did not cause a significant increase in the number of deaths.
Faried Abdullah, director of the AIDS and Tuberculosis Research Office of the South African Medical Research Council (SAMRC), posted on social media "Twitter" that the current outbreak came and went quickly, and was not as severe as the variant Delta. "It took only 4 weeks to reach the peak, followed by a sharp drop in the next 2 weeks."
In the third month of Omiljung's appearance, scientific research was also frequently reported. Some studies from different medical systems, different countries, and different ethnic compositions have found that the infection of Omikerong shows clinical manifestations such as youthfulness and mild disease.
Infected people are younger
On December 30, 2021, JAMA took the lead in releasing the first peer-reviewed retrospective study of clinical manifestations in people infected with Omikejong. The paper was completed by Netcare, a consortium of private medical institutions in South Africa.
The study pointed out that since 2020, South Africa has experienced four waves of pandemics. include:
Wave 1, June-August 2020, the original strain is the main epidemic strain;
Wave 2, from November 2020 to January 2021, the mutant strain Beta came to the fore and became the main popular strain;
Wave 3, from May to September 2021, the variant Delta won, causing a pandemic;
Wave 4, after November 15, 2021, saw another spike in infections as the mutant strain Aomi Kerong was detected.
Based on the progress of the outbreak, Netcare researchers sampled peak hospital admission data in each wave of the outbreak, and focused on the analysis of hospitalized patients in the 3rd and 4th waves.
The results showed that at the peak of infection in Omikerong, the infected people were generally younger, with a median age of only 36 years, and mostly women.
In wave 3, led by the variant Delta, the median age of infected people was 59 years old, the "oldest" of the four waves.
Previously, SSRN released a preprint study of The Lancet, which also suggested that Omi kerong may be more dangerous to young people.
The study analyzed 18,817 people who tested positive for Ami Kerong and admitted to the hospital, and found that 1,151 people were 20 years old and younger, accounting for 17.68%. At the peak of delta transmission, 3.8% (161/4,217) were infected and hospitalized in the same age group.
Symptoms of infection are mild
In addition to age characteristics, the above studies are all concerned with the virulence of Omikeron.
The WHO has previously warned that the combination of Delta and Omikerong variants could cause a "tsunami" of infection that overwhelms the health care systems of various countries.
But data from South Africa's Ministry of Health shows that Omiljung has become a major endemic strain in the region, causing hospital admissions to rise sharply, but at a much slower rate than expected. Compared to The First Wave in South Africa, the chances of hospital admission to Ami kerong infection are about 30% lower.
South Africa COVID-19 datasheet from 6 March 2020 to mid-December 2021.
Gray is the number of hospitalizations confirmed by COVID-19; the black curve is the number of new infections; and the red curve is the number of hospital deaths. /SSRN
In JAMA's article, the researchers further analyzed the prognosis of hospitalized patients and found that multiple data all supported a "decrease in toxicity."
First, both the hospital stay rate and the average length of stay were significantly reduced. In the first three waves, 68%-69% of infected people were admitted to hospital. By wave 4, admissions had fallen to 41.3 percent. At the same time, the median number of hospital stays for Those infected with Omikerong dropped from 7-8 days to 3 days.
Second, oxygen inhalation and mechanically assisted ventilation rates decreased. The latter, in particular, has fallen from 12.4% in the third wave to 1.6% now.
Third, the complications of infected people have decreased significantly, and the case fatality rate has dropped sharply. When Delta is the dominant endemic strain, 29.9% of patients need to be transferred to intensive care, with a case fatality rate of 29.1%. After the Opmiqueron pandemic, the ICU rate for infected people was 18.5% and the case fatality rate was 2.7%.
A similar discussion is found in the Lancet preprint study. Researchers say that in wave 4, 28.8 percent of hospitalized cases were severe. In wave 2 and wave 3, the severe illness rate was 60.1% and 66.9%, respectively.
On January 1, 2022, Houston Methodist, one of the largest medical systems in Texas, USA, also uploaded a paper on the clinical manifestations of Omicron on the preprint platform medRxiv, which was almost consistent with the conclusion published in JAMA by Netcare in South Africa: it was observed that infected people were significantly younger, had shorter hospital stays, required less respiratory support, and had fewer severe cases.
The dawn of the end of the epidemic?
At the beginning of the emergence of Omikeron, the medical and scientific circles were mainly worried that the variant carried a large number of mutations and were located on the spike protein. This makes the virus more infectious. Studies in South Africa have proposed that the rate of re-infection in Omiquerong is 3 times higher than that of other strains.
But fortunately, the poison of Omikeron seems to be weakening. Relevant research analysis said that this may be the result of multiple factors working together.
First, including some animal models, showed a decrease in lung virulence in Omexjong. According to the Imperial College London study, it seems to be more inclined to infect the upper respiratory tract, especially the susceptible nasal mucosa. It is no longer as easy to infect the lungs as the earlier strains such as Delta.
A joint Japan-U.S. preprint study showed that mice infected with Omikerong developed less lung damage. Another Belgian study came to a similar conclusion. In addition, Hong Kong, China, used lung tissue samples of COVID-19 patients collected during surgery to conduct studies and found that Omexon grew slower in these samples than other strains.
This may mean that the severe rate of Infection in Omikeron has decreased. But because the virus replicates more frequently in the upper respiratory tract, it also makes it more transmissible.
Second, Bloomberg cites research that the immune system's second line of defense— T cells and B cells— can still recognize and attack Omi kerong.
Virus published on January 2, 2022, the Hong Kong University of Science and Technology in China and the University of Melbourne in Australia joined hands to analyze more than 1,500 gene fragments of new coronavirus proteins, which can be recognized by T cells produced by covid-19 survivors and vaccinators. The results showed that Aumecreon had difficulty escaping the attack of the T cell immune response through mutations. This suggests that the T-cell immune response produced by vaccination or natural infection can still protect the body from severe illness.
Omi kerong or "new pop"
The WHO is concerned that the South African study may not be "globally indicative".
This has to do with the demographics of South Africa. "South Africa has a relatively young population, with a median age of 27.6 years. In the UK, it is 40.5 years old. As a result, the Aumechjong outbreak experienced by South Africa may be different from that of countries with ageing populations. The BBC reported.
Secondly, South Africa has a relatively low vaccination rate, with only 26 per cent of the population being fully vaccinated, and the highest vaccination rate of those over 60 years of age, reaching 58.4 per cent, followed by 40-59 years (54.3%) and 20-39 years (31.7%). According to the Lancet preprint study, only 5.8 percent of those under 20 years of age had been vaccinated against COVID-19 during its study period. This could all be the reason why the country's young people are more susceptible to Aomi Kerong.
Young people have a low prevalence of chronic underlying diseases, and even if infected, the degree and progression of the disease will be significantly better than that of the elderly population.
New York Times popular science writer Carl Zimmer agreed that the clinical manifestations of Omicron were milder. However, due to its rapid spread and high contagiousness, this will cause more people to be infected. Therefore, even if the rate of severe illness is low, it can put a huge strain on the medical system.
He also noted that the popularity of Ami kerong was more like a "new pop." The incubation period is extremely short, and patients will soon develop clinical manifestations after infection. From a public health perspective, people infected with Ami kerong can be more effective in alleviating the outbreak if they can be quickly isolated after symptoms develop.
However, as of now, many countries such as the United Kingdom and the United States have updated their epidemic prevention strategies and shortened or even cancelled some quarantine requirements. In the United States, close contacts who have been vaccinated in full dose and have no symptoms are not required to quarantine, but must wear a mask for 10 consecutive days of daily activities.
The Wall Street Journal also warned that many European and American countries that are fighting Against Opmi kerong may not be able to recreate the South African experience. In addition to the age composition, natural infections, etc., it is also necessary to pay attention to seasonal factors. "South Africa is in the summer, and COVID-19 tends to spread more easily in the winter – this is what Europe and the United States are experiencing."
Source:
1.Characteristics and Outcomes of Hospitalized Patients in South Africa During the COVID-19 Omicron Wave Compared With Previous Waves. JAMA. doi:10.1001/jama.2021.24868
2.SARS-CoV-2 T Cell Responses Elicited by COVID-19 Vaccines or Infection Are Expected to Remain Robust against Omicron. Viruses. doi.org/10.3390/v14010079
3.South Africa says Omicron wave may have peaked. BBC
4.Omicron threat has a silver lining? Cases soar but new data puts end in sight. mint
5.Omicron cases less severe than other waves, hospitalisation rate lower, shows study in Lancet. The Print
6.COVID-19 Omicron wave in South Africa characterized. Medical Press
7.Clinical Severity of COVID-19 Patients Admitted to Hospitals in Gauteng, South Africa During the Omicron-Dominant Fourth Wave. SSRN. doi.org/10.2139/ssrn.3996320
8.Early signals of significantly increased vaccine breakthrough, decreased hospitalization rates, and less severe disease in patients with COVID-19 caused by the Omicron variant of SARS-CoV-2 in Houston, Texas. medRxiv. doi.org/10.1101/2021.12.30.21268560
Source: Medical community
Image source: WHO
Editor-in-charge: Dai Dai Zhangli
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