Science‘COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.
In late June, Sunny de Zhang developed nausea, shortness of breath, sore muscles and runny nose. At first, she thought it might be the lasting effects of her COVID-19 infection in the spring. De Zhang, 22, tested positive on April 17 and experienced mild symptoms for about 2 weeks. She tested negative on May 2 at the time of saying goodbye to her deceased grandmother – returning to work as a nursing internet at a hospital in Rotterdam, the Netherlands.
But when her symptoms reappeared, the doctor recommended that she be re-examined. “It will be strange to have a restoration soon, but it is not impossible,” he told De Jong, who again lost his sense of smell and had abdominal pain and diarrhea.
The call came on July 3 from his municipal health service. De Zhang tested positive again. “You’re playing me!” She remembered what she had said.
Scientists are very interested in events like hers, which are still rare but on the rise. Restructuring points out that immunity against COVID-19 is fragile and may decline relatively quickly, with implications not only for the risks faced by recovered patients, but also for how long future vaccines may protect people. “The question everyone wants to answer is: Will that second time be harder or not?” Says Derek Cummings, who studies epidemiology at the University of Florida. “What do reconstructions teach us about SARS-CoV-2 immunity in general?”
South Korean scientists Announced Suspicious restorations from April, but a case is due by August 24 to come Officially confirmed: A 33-year-old man who was treated in a Hong Kong hospital for a mild case in March and tested positive again at the Hong Kong airport on August 15 after returning from a trip to Spain. Since then, at least 24 other restorations Officially confirmedBut scientists certainly say this is an understatement.
For a recurrence to count as an event, a patient should have a positive polymerase chain reaction (PCR) test at least twice between months with no symptoms. But Dutch national health and environmental virologist Chandel Reisken explains that a second test may also be positive because the patient’s viral RNA is a remnant of viral RNA that did not reuse the original infection in their airways because one infection is caused by two viruses at once. Suppressed but not completely eradicated virus. Therefore, most magazines like to see two complete viral sequences from the first and second diseases, which are quite different, says Paul Moss, a hematologist at the University of Birmingham. “The menu is too high,” Moss says. “In many cases, there is no genetic material.”
Despite that, many labs do not have the time or money to complete the case. As a result, the number of genetically proven restorations is orders of magnitude lower than the suspected restorations. There are 50 such cases in the Netherlands alone, Brazil95, Sweden150, Mexico 285, And Qatar at least 243.
The Hong Kong patient’s second infection is milder than the first, which immunologists expect, because the first infection usually produces some immunity. This may explain why restoration is still relatively rare, says Maria Elena Potassi, molecular virologist at Baylor Medical College and Texas Children’s Hospital.
Early cases begin to lose their immunity and become more common over the next two months. Reconstruction with the four corona viruses that cause the common cold occurs on average after 12 months, according to a team led by virologist Leah van der Hoek at the University of Amsterdam Medical Center Recently shown. Van der Hoek thinks COVID-19 might follow that pattern: “I think we will be ready for the restoration waves in the coming months.” “This is bad news for those who still believe in herd immunity through natural infections,” he says, and a worrying sign for vaccines.
Others are less optimistic. Antibodies though Will decrease significantly within monthsFor patients with less severe disease – they are Sometimes that will continue, Even in mild cases. Neutralizing antibodies, The most important type, as well Memory B cells And T cells Seems relatively stable at least 6 months, a Released November 16th Shane Grotti, lead author of the La Jolla Institute for Immunology, said: Said The New York Times.
And are Notes Like the other two serious human diseases caused by the corona virus, people with severe COVID-19 also receive strong responses. Acute acute respiratory syndrome (SARS) Other Middle Eastern respiratory syndrome. Both induce high antibody levels lasting up to 2 years, and T cell responses to SARS Can still be detected for a long time. “I expect most restorations to be asymptomatic,” says Antonio Bertoleti, an epidemiologist at the National University of Singapore, because of this continued immune protection. “Because you will continue to boost and train your immune system,” he says, restructuring can even be a good thing.
Not all the restorations seen so far have been minor. “We see all the different combinations,” Ruskan says. Louisiana Ribeiro, a surgeon in Rio de Janeiro, fell ill for the second time. It was so bad. In March he was first victimized by a colleague, developed mild symptoms and then tested negative. Three months later, Ribeiro showed symptoms again — she could no longer feel her breakfast, she says — but she did not get an immediate test because she thought she was immune. As she got more and more tired, she demanded a computerized tomography scan. “It showed half the damage to my lungs,” Ribeiro says. “‘This is clearly COVID,’ ‘the radiologist told me. I did not believe it, but I tested positive.”
Ribeiro believes he was re-immunized by a patient in the intensive care unit where he works, and his second episode may have been worse because viral aerosols produced during a medical procedure entered his lungs. But she also has another theory: “In the meantime, the virus may have become more viral.”
So far, there is no evidence of mutations that make the virus highly pathogenic or help to prevent viral immunity. But a team at a Swedish medical center in Seattle says there may be a printer they recently wrote. This group describes a person who became infected again 4 months after the infection in March. The second virus had a mutation that is common in Europe, causing a slight change in the spike protein of the virus, which helps it to break down in human cells. Although the symptoms were mild a second time, neutralization tests showed that antibodies to the virus exposed to the first did not work properly in the second, the authors point out, “which could have significant implications for the success of vaccination programs.”
Some scientists are concerned about another scenario that exacerbates the second chapter: advanced disease, in which the false immune response to the first infection exacerbates the second disease. In dengue fever, for example, antibodies to early infection Another serotype can help dengue viruses enter cells, Which leads to a very serious and sometimes dangerous second infection. In some other diseases, the first infection triggers ineffective, neutralizing antibodies and T cells, which in turn inhibit the second most effective response.
A recent In advance Patients with the most severe COVID-19 infection released by Chinese researchers may have ineffective antibodies that are more prone to severe relapses. There is no evidence so far from rehabilitated patients that COVID-19 has improved disease function – although scientists have not ruled it out. Vaccination against certain diseases may later trigger the spread – a known or suspected complication of vaccines against dengue Respiratory syncope virus In humans and A corona virus infection in cats. But Cummings says candidate Govt-19 vaccines have no evidence to do so. “Having worked with dengue, there is no empirical basis for advanced disease, while I can say that it was very strong in dengue.”
Both de Jong’s virus samples were sequenced in Ryazan’s laboratory, with surprising result: the footage was not identical, but showed very similarity, with RIVM virologist Harry Wennema claiming in April that the virus had not been eradicated and that it had begun copying again. “I was very depressed after that first episode because my grandmother died,” says De Zhang. “It could have had an impact on my immune system.”
This distinguishes his case from a real reconstruction — although Vennema claims that they should be considered identical, in both cases the immune system fails to provide a protective response. His lab found at least one similar case, and he says some unconfirmed reconstruction may actually be a re-emergence of the original virus.
Stanley Perlman of the University of Iowa says other corona viruses continue to cause infections. In 2009, his team Showed The mouse corona virus that causes an encephalitis can persist in the body and trigger immune responses, even if it is not copied. And inside A front axle Released on November 5, a team of American scientists shows that SARS-CoV-2 can last for several months in the gut. They suggest that persistent infections may help explain the abnormally long-term symptoms that affect some COVID-19 survivors.
De Zhang is experiencing some of those symptoms. Although he tested negative in September and had high levels of neutralizing antibodies and claimed to be protected for at least two months, he still suffers from gastrointestinal complaints, fatigue and cognitive impairment. De Zhang says his story is a warning to those infected with the virus and thinks they are now indestructible: “Please be careful. You can get it back. ”