A doctor in Israel has been diagnosed with Covid-19 twice, months apart and after testing negative between the two samples, according to local media.
The doctor, who worked at Sheba Medical Center in the town of Ramat Gan, six kilometers east of Tel Aviv, is said to have recovered from his first episode of the coronavirus.
She had tested positive in April but recovered from the disease, which infected an estimated 55,000 people in Israel, then tested negative twice in May and June.
But this month, after coming into contact with an infected patient, the anonymous doctor tested positive for Covid-19 again.
The case is one of many possible “re-infections” that raise questions about the immunity people develop after catching the coronavirus, and whether people can catch it more than once.
So far, there have been no scientifically proven cases of someone catching it twice, with experts tending to blame inaccurate test results or long illness. Some say it is not uncommon for virus parts to continue circulating even after recovery.
The doctor worked at Israel’s largest hospital, Sheba Medical Center in Ramat Gan (pictured). There is no indication that the doctors pictured are involved in the story
The female doctor has reportedly tested positive for the coronavirus again after coming into contact with an infected patient, The Times of Israel reported.
The report, originally published on the country’s Channel 13 newscast, implies that she was re-infected with the virus when she had already recovered from it.
Traditional understanding of viruses suggests that people who have previously had Covid-19 should develop at least a temporary level of immunity.
But cases like this challenge the idea of natural protection.
A hospital patient reportedly suffered the same phenomenon recently.
Along with concerns about re-infection, there are also signs that people may just stay sick for a long time with the virus still circulating in their bodies.
Professor Gabriel Izbicki, from the Shaare Zedek Medical Center in Jerusalem, said it was “scary” how long people suffered from the disease.
He told The Times of Israel: “More than half of patients, weeks after testing negative, are still symptomatic.”
The case is one of a number that appears to show people are diagnosed with coronavirus more than once.
A scientific article titled “A case report of possible reinfection of the 2019 novel coronavirus” was published in the United States recently describing the case of an 82-year-old man hospitalized twice with the virus.
THE MYSTERY OF IMMUNITY TO COVID-19
Scientists are still not sure if people can get Covid-19 more than once or if they become immune after their first infection.
With some illnesses such as chickenpox, the body can remember exactly how to destroy it and can push it away before symptoms start if it returns to the body.
But it is so far unclear whether people who have had coronavirus can contract it again.
Tests have shown that many people who recover have antibodies – which can produce future immunity – but it is not known whether there are enough.
A doctor, Professor Karol Sikora, said he found that only 10% of people known to have had Covid-19 had actually developed antibodies.
This means that it is difficult to measure whether they could fight it immediately if they are infected again.
Another study, conducted by the University of Melbourne, found that all patients in a group of 41 developed antibodies but, on average, they were only able to fend off 14.1% of viruses if they were exposed a second time.
Research on other similar coronaviruses, which also infect humans but usually only cause mild illness, has found that people tend to develop protective immunity, but their antibody levels drop within a few months and that they could be re-infected after about six months.
However, antibodies are only one type of substance that can produce immunity.
Others, including white blood cells called T cells and B cells, can also help the body fight disease, but are more difficult to find using tests currently available.
The Melbourne study found signs of high numbers of coronavirus-specific B cells and T cells in recovered patients, suggesting these types of immunity may be stronger than antibodies.
They called for more research on the subject.
A promising study in monkeys found they were unable to catch Covid-19 a second time after recovering from it, leading scientists to believe the same could apply to humans.
Rhesus monkeys have been deliberately re-infected by Chinese scientists to test their body’s reaction.
Because the coronavirus has only been known to scientists for seven months, there hasn’t been enough time to study whether people develop long-term immunity.
But, so far, cases of people infected more than once have not been numerous or convincing.
The unidentified man went to the emergency room at Massachusetts General Hospital after suffering from a high fever for a week.
He tested positive for Covid-19, then his condition rapidly worsened while in hospital.
Doctors managed to save his life with a long stay on a ventilator, but he fell ill again less than a fortnight later, despite testing negative twice before being released.
He again needed intensive care and recovered a second time, although his condition was not subsequently revealed.
Doctors explained in the American Journal of Emergency Medicine how it was possible the man recovered and tested negative, but fell ill again.
His doctors said that rather than being infected twice, it is likely that he never made a full recovery the first time around and that the tests weren’t sensitive enough to notice that he still carried the virus.
The doctors, led by Dr Nicole Duggan, said: “Many viruses demonstrate a prolonged presence of genetic material in a host, even after the live virus is cleared and symptoms resolved.
‘Thus, the detection of genetic material by [swab test] alone does not necessarily correlate with active infection or infectivity.
“Observational data suggests that viral shedding of SARS-CoV-2 may last 20 to 22 days after symptom onset on average, with some peripheral cases showing shedding as long as 44 days. “
They said that in a 71-year-old woman, a study found she continued to test positive for Covid-19 five weeks after her symptoms resolved.
Because the virus wasn’t first discovered until December, scientists haven’t had a chance to determine how it affects people in the long term.
In a study by the University of Amsterdam, researchers suggested that the coronavirus might act similarly to other coronaviruses that cause colds and other infections.
The researchers followed 10 volunteers for 35 years and tested them each month for four seasonal and weaker coronaviruses named NL63, 229E, OC43 and HKU1.
These viruses are much more common and cause mild illnesses similar to the common cold.
They found that those who had been infected with the strains – from the same family as SARS-CoV-2, the type that causes Covid-19 – had “an extremely short duration of protective immunity.”
Levels of antibodies, substances stored by the immune system to allow the body to fight off invaders in the future, dropped by 50% after six months and disappeared completely after four years.
Studying how people recover from viruses in the same family as the one that causes Covid-19, scientists say their research is the most comprehensive analysis of how immunity works against the disease that has emerged in China. ‘last year.
Writing in the study, which has not yet been published in a scientific journal or reviewed by other scientists, the scientists said: “Seasonal coronaviruses are the most representative group of viruses from which to conclude general characteristics. coronaviruses, especially common denominators such as immunity dynamics and susceptibility to reinfection.
“In conclusion, seasonal human coronaviruses have little in common other than the common cold.
“Yet they all seem to induce short-lived immunity with rapid loss of antibodies. This could well be a general denominator for human coronaviruses.