Covid and Omicron Options: Gamma, Iota and Mudan lessons

In early 2021, Colombian scientists discovered a dangerous new variant of the coronavirus. Finally, this variant, called Mu, had several dangerous mutations, which experts believed would help the immune system avoid defenses.

In the following months, Mu spread rapidly in Colombia, sparking a new surge in Covid-19 cases. In late August, it was identified in dozens of countries, and the World Health Organization called it an “option of interest.”

“Mu is starting to make some noise around the world,” said Joseph Fauver, a genomic epidemiologist at the University of Nebraska Medical Center and author of a recent study on the variant.

Then it was ripe. Today, this option has completely disappeared.

For every Delta or Omicron there is a Gamma, Iota or Mu, they originated locally but have never reached world domination. Experts say Omicron remains an important public health priority, but there are lessons to be learned from these fewer breeds.

Joel Wertheim, a molecular epidemiologist at the University of California, San Diego, said: “There is no reason to stop the virus from adapting and growing.” “And seeing how he did it in the past will help us prepare for what he can do in the future.”

Rand’s research has also revealed gaps in observations and policy flaws – suggesting that US international travel bans have been ineffective and that the virus has been successful, making it more important to be infected in the early stages of a pandemic. than immune avoidance.

The study also emphasizes the importance of context; Options that affect in some places may never take place in others. As a result, it is difficult to predict which options will prevail, and staying ahead of future options and pathogens requires comprehensive, almost real-time monitoring.

“We can gain a lot by looking at the genomic sequence of the virus and saying, ‘This is worse than the other,'” he said. Wertheim said. “But the only way to really know is to see its spread, because there are so many dangerous options that have never been saved.”

The coronavirus is constantly evolving, and most new variants are never detected or named. But others ring the bell because they spread so quickly or their genomes look dangerous.

Both were correct about Mu spread in Colombia. Mary Petrone, a genomic epidemiologist at the University of Sydney and author of the new Mu paper, said: “It contains several mutations that people can observe very carefully.” Several mutations in its protein have been documented, including in immune-escaping variants such as Beta and Gamma.

In a new study that has not yet been published in a scientific journal, scientists have compared its biological properties to those of Alpha, Beta, Delta, Gamma, and the original virus. Mu did not replicate faster than other options, they found, but it was the most immune of the group – Omicron, Dr. Said Fauver.

By analyzing the genomic sequence of Mu samples collected from all over the world, the researchers reconstructed the variant distribution. They concluded that Mu appeared in South America by mid-2020. It then spread for months before it was identified.

In many parts of South America, genomic observation was “bad and incomplete.” Jesse Bloom is an expert on viral evolution at the Fred Hutchinson Cancer Research Center in Seattle. “If he had better control over the areas, it would be easier to quickly assess how much he is worried about Mu.”

Mu showed another challenge. It contained a type of mutation known as a rare frame mutation in coronavirus samples. Such mutations have been identified as errors, and scientists, including Dr. Fauver, who tried to upload their Mu sequence to GISAID, used the international repository of viral genomes to track new variants.

This complexity has led to delays in sharing Mu consistency with the public. The researchers found that the Mu cases were longer than the Delta cases between the time the virus sample was collected from the patient and before it became publicly available on GISAID.

“The genome itself was basically creating artificial observation gaps,” he said. Said Fauver. “It’s at least in our experience that we haven’t been able to get information for weeks while we’re trying to produce it in a few days as usual.”

(Researchers and the repository have highlighted the importance of GISAID quality control systems.)

If you combine these observation gaps with this immune escape, the option seems to work. But that did not happen. Instead, it spread to continents other than South and Central America, but it was not widespread when it arrived, scientists say. “This is an indication that this option is not necessarily suitable for the people of North America and Europe, as we expected,” he said. Said Petrone.

This was because Mu himself was competing with an even more dangerous option: Delta. Delta Mu was not good at avoiding antibodies, but she was more contagious. “So, eventually, the Delta has become more widespread,” Dr. Bloom said.

Exploring successful options will tell only half of the story. “Non-dominant options are, in a sense, negative control,” the doctor said. Said Petrone. “They tell us what’s not working and help fill the educational gaps around the fitness option.”

Delta Mudan has also gone through several immune escape options, including Beta, Gamma and Lambda. This pattern shows that immune escape alone was not enough to overcome the infectious version of the virus – or at least in the early stages of this pandemic, few people were immune.

However, vaccinations and several waves of infection have changed the immune landscape. According to scientists, the option with higher immunity should now have more advantages, which is part of the fact that Omicron is so successful.

Another recent study in New York suggested that immune fugitives Gamma would work better in areas with high levels of pre-existing immunity because in some cases they were hit hard by the first Covid wave. “We can’t see a new variant in a vacuum because it appears in the shadow of all the variants that came before it,” he said. The author of the study was Wertheim.

Indeed, the collision of past options shows that success depends on context. For example, New York City may be the birthplace of the Iota variant, which was first found in virus samples collected in November 2020. Petrone. Even after the arrival of the more popular version of Alpha, Iota remained the dominant version of the city for several months and eventually disappeared.

But in Connecticut, where both Iota and Alpha appeared in January 2021, things were different. “The alpha flew away right away, and Iota didn’t have a chance,” the doctor said. Petrone led the study of options in both regions.

A similar pattern began to play with several descendants of Omicron. BA.2.12.1 in the United States, the first detected subvariant to fly in New York, creates a new wave of BA.4 and BA.5 in South Africa.

Sarah Otto, an evolutionary biologist at the University of British Columbia, is another reason to study these declining options. An option that does not fit at a certain time and place may go away at another time. In fact, his unhappiness may be due to the fact that it appeared very quickly. “People with immunity may not be enough to really boost this option.” Dr. Otto said.

But the next option of concern could be the offspring of an immune-defying offspring or something similar that has never been accepted, he said.

Reviewing previous options can give you an idea of ​​what worked or didn’t work in their coverage. The new Gamma study adds that international travel bans, at least because the United States has enforced them, will not prevent the option from spreading globally.

Gamma was first identified in Brazil in late 2020. In May of that year, the United States banned most non-American citizens from entering the country from Brazil, a restriction that remained in effect until November 2021. But gamma has been identified in the United States. The state expanded to dozens of states in January 2021 and soon after.

Since gamma has never dominated the world, a study of its prevalence described the effectiveness of travel bans “clearer”. said Tetyana Vasilyeva, a molecular epidemiologist and study author at the University of California, San Diego. “When it comes to exploring options like Delta, for example, something that has led to a big epidemic everywhere – sometimes it’s hard to find samples because it’s so large-scale and so fast,” he said. .

In a global health emergency, when the virus is changing rapidly, there is a clear impulse to focus on the future, Dr. Said Fauver. As the world’s attention turned to Delta and then Omicron, he and his colleagues discussed continuing their research on the old news Mu.

“We’re like,‘ Does anyone else care about this? Fauver remembered. “But we think there is still room for high-quality research that asks questions about previous options of concern and tries to rethink what happened.”

Leave a Comment

Your email address will not be published.