The science behind the rapid spread of Omicron

These benefits mean that Omicron is spreading around the world at an astonishing pace. According to the World Health Organization, it has been detected in 77 countries since South African scientists first reported its presence last month, and probably in most other countries as well.

A case of Omicron was detected in the United States, Europe and Africa as a whole, and China, maintain strict border controls and strict regimes to control even small outbreaks.

“Omicron is spreading at a rate not seen in previous variants,” said WHO Secretary-General Tedros Adanom Gebreyes recently.

There are signs that the variant is associated with a disease that is less severe than previous versions of the virus. However, scientists say that factors such as immunity levels and demographic characteristics can cause the severity to vary from place to place, and even if it is not so dangerous, its ease of transmission is still Omicron. Warn that it means it can cause a wave of illness and death.

The surprisingly contagious examples of Omicron are on the rise.Following the November 26th Christmas Party for Renewable Energy Companies At the Oslo restaurantAccording to the Norwegian Institute of Public Health, 80 of the 111 guests were coronavirus-positive, and gene sampling suggested that all were likely to be omicrons.

In Hong Kong, a 36-year-old man was identified as follows: One of the earliest known cases of Omicron At one of the quarantine hotels in the city on November 13th. Five days later, a 62-year-old man staying in a room across the corridor also tested positive for the mutant, despite no contact with his neighbors. Researchers have concluded that the variant must have crossed the corridor.

In England Omicron replaced Delta as a major variant Coronavirus infections in the UK and Scotland have been less than a month, and the same is only a few days late in Denmark, according to Danish health officials. According to a committee of scientists advising the state government, it is already the predominant variant in Ontario, Canada, accounting for 51% of new cases. UK health data suggest that Omicron cases have doubled in most parts of the country within two days.

In the United States, the delta type accounted for about 96% of all cases and the omicron type accounted for about 3% in the week leading up to December 11. More numbers can be seen in some areas. In New York and New Jersey, Omicron was estimated to account for about 13% of Covid-19 cases.

Behind the rapid spread of Omicron is a series of mutations that dominate the older mutants.

Of the approximately 50 mutations in Omicron, at least 30 are in pesplomers. This is a structure that helps the virus invade cells and is also the main target of vaccines.

Lab tests in South Africa, Sweden, the United Kingdom, and the United States have shown that antibodies that prevent mutants from entering cells are less capable than other strains, and Omicron has been previously vaccinated or infected. Much better at infecting. This means that even highly vaccinated populations can spread rapidly.

Modeling quotes published Friday by researchers at Imperial College London Risk of reinfection with Omicron It is 5.4 times the delta, indicating limited protection from previous infections. This non-peer-reviewed study also reported reduced vaccine efficacy against Omicron infection after two doses compared to Delta.

Almost 70% of the UK’s population is fully vaccinated, but Omicron has driven a record increase in incidents, demanding the government to work from home as much as possible, and other days before Christmas. It limits mixing with households and builds additional immunity that encouraged them to take booster shots. Denmark and Norway have also tightened public health restrictions to defeat the wave of incidents.

“If the virus can partially circumvent the immune response elicited by either a previous infection by another variant or a vaccine, the virus can infect and spread more efficiently. This is Omicron. “It’s found in variants of,” said Lawrence Young, a virologist and professor of molecular oncology at Warwick University.

Increasing evidence suggests that mutations in Omicron may provide inherent transmission benefits in addition to the ability of the body to evade the immune response.

One study that has not yet been peer reviewed Researchers in Hong Kong have discovered that Omicron is infected and becomes a multiple. 70 times faster than the delta variant in the airways. This may explain why the new variant seems to propagate faster.

But in the lungs the situation was different. Researchers have found that Omicron has a lower lung replication efficiency than the original version of the virus. This helps explain why Omicron is associated with less severe illnesses in many people infected.

Another study, which has not yet been peer-reviewed, seems to support the findings of the Hong Kong team. Researchers have shown that the Omicron pseudovirus (a synthetic version of the Omicron variant) is superior to the Delta pseudovirus and the original version of the virus in infecting cells.

Julian Tan, a clinical virologist at the University of Leicester and a professor of respiratory medicine, said that if the virus propagates faster, it “may begin to spread to others sooner.”

According to UK public health officials, the advantage of Omicron is that the time it takes for a newly infected person to infect others appears to be perhaps 3 days shorter than 6 days or more in Delta. To do. They also estimate that the risk of someone spreading the virus to other members of the family is three times higher. Higher in Omicron compared to Delta..

One metric that epidemiologists use to measure the infectivity of a virus is its effective reproduction number, or R, the average number of people infected. This will vary from place to place, depending on the level of immunity and public health policies being implemented to control the infection. The higher the value, the more infectious the virus is.

Susan Hopkins, head of the UK Health and Security Agency, told parliamentarians Thursday that her agency estimates Omicron’s current R-value to be between 3 and 5. 1.2, she said.

Scientists say that even if Omicron proves to cause mild illness, its high levels of infection are problematic, especially for those who have been vaccinated or who have some immunity from previous infections. Say there is. Booster shots have been shown to increase protection against infection. Scientists are widely optimistic that vaccines will help prevent serious illness and death from Omicron.

Awaiting peer review by a disease modeler at the London School of Hygiene and Tropical Medicine, the paper describes some possible scenarios in the UK over the next few months: Omicron continues to spreadThis depended on the extent to which the mutant was able to evade immunity and how effective the booster was in delaying infection. All scenarios show more cases, hospitalizations and deaths.

In an interview with The Wall Street Journal’s journal podcast released Thursday, President Biden’s chief medical adviser, Anthony Fauci, said, “It’s better to pay attention to the predictions that it’s not that serious, so it’s better. Would be. “

“If more people are infected, the fact that more people will be infected may overcome the lack of severity.”

Write to Jason Douglas [email protected] And Saratoi [email protected]