On an early uncertain day of the coronavirus pandemic, scientists brought one declaration of comfort. mutation Quite a bit slow. If that remains true, the virus will not change much as it will quickly become more dangerous. Long-standing durability protection.
What actually happened was that SARS-COV-2 began mutating rapidly, becoming more contagious first, then avoiding immunity, causing groundbreaking infections and reinfection. After 5 years and variant alphanumeric soup, most of us covided at least once. The vaccine is still being updated to match the new circulation variant. And the virus itself is still changing.
In fact, scientists were also right and wrong about the rate at which SARS-COV-2 mutates. The mutation rate when this virus jumps from person to person is not really impressive. However, scientists were not aware of the two-second accelerated evolutionary track. If SARS-COV-2 infects a single immunodeficiency patient, it can last for several months, during which time it accumulates countless mutations.
And if we are unlucky, that very mutated virus may spread to others. This could be the origin of the omicron with more than 50 mutations in fall 2021. This is an incredible leap of evolution. Omicron appeared to have achieved four or five years’ worth of expected evolution in just a few months, Jesse Bloom, who studies the evolution of the virus at the Fred Hutchinson Cancer Center, told me at the time. . These mutations allowed Omicron to cause a massive wave of infection, even among vaccinated people.
Scientists now believe that chronic infections in immunocompromised patients are a key driver of the Omicron and later variants. Despite the urgent decline in COVID surveillance, researchers are looking at chronic infections for signs of the future.
Looking back, there were clues from the beginning. At the start of the pandemic, New York researchers, including Hart of Van Bakell, a geneticist at Ikaan School of Medicine in Mount Sinai, began sequencing the virus from Cancer patients They tested positive for SARS-COV-2 in March and April 2020, and continued to test positive for up to two months. The patient was unable to remove the virus because his immune system was weakened by illness and cancer treatments he received. The study, published in December 2020, concluded that immunocompromised covid patients may need a long period of isolation so that they do not unconsciously spread the virus. (These chronic infections in immunocompromised people are unlike long covids that do not necessarily involve continuous shedding of the virus.)
That same month, a Preprint More dots are stitched together from a group led by British Ravindra Gupta. Gupta and his colleagues discovered immunodeficiency patients with prolonged infectious diseases who were treated with antibodies from Covid survivors solely to help the virus acquire a new, curious mutation. In particular, two mutations gave the virus a slight edge to infectivity and antibody avoidance. They suggested that immunodeficiency hosts could provide the basis for ideal viral training. In this case, the injected antibodies from COVID survivors are likely to contribute to the defenses the patients themselves had, but not enough to fully clear the infection even together.
The virus from that particular patient probably hadn’t spread far. Most of them aren’t. However, countless chronic infectious diseases around the world that expose the virus to similar immune defenses may have ultimately repeated the same combat-tested mutations over and over again. In fact, mutations similar to two UK patients quickly appeared in variants like Alpha and Omicron that cleaned the world, Gupta recently told me. And in 2021, we found out that several surprising variants carry different mutations. Researchers in New York were first observed in immunocompromised patients at the start of the pandemic. (Sinai Mountain researchers led by Van Bakel and Viviana Simon matched minor variants from immunodeficient patients Other infectious diseases in New York Citybut it didn’t seem to have spread any further. )
No more infamous COVID variants have been directly followed by a single immunodeficiency patient. However, indirect evidence has accumulated over time that many variations develop in this way. Chronic Infectious Diseases, scientists have now been observed again and again, creating a clear pattern of mutations. It is an excessive amount of changes in spike proteins (which help to penetrate human cells), but not the rest of the virus. This pattern is clearly seen in both the Ba.1 and Ba.2 versions of Omicron, as well as the variant that produced Jn.1 that driven Covid Surge last winter. Bloom now says he has “very high confidence” that these variants come from chronic infections. The evidence is not so clear in other variations, he told me, but they may have evolved very well as well.
Long before Covid, Bloom was tracking The evolution of influenza During chronic infection in four immunodeficiency patients; several mutations in these patients eventually appeared in seasonal influenza. I wrote about this study when it was published in 2017 when it was intrigued by the possibility that chronic infections could predict flu changes each year. At the time, this was a very novel idea.
The evolution of influenza and covid differs in important ways, but chronic COVID infections are also being considered as a harbinger of the future. “These actually tell us a lot about future tricks that SARS-COV-2 can come up with,” says Simon, a microbiologist at Icahn School of Medicine in Mount Sinai. To discover what they are, she and Van Bakel now Research Project To create better tools for sequencing chronic infections and to better understand which immunodeficient patients are at the highest risk of carrying them. What they found might be a future preview of Covid.
