What if Covid-19 Immunity Does Not Last? By Brian Simpson

     This will be a big, big, problem for the position held by Sweden, that herd immunity will arise, sooner or later. Yes, but what if it does not?

“the most critical unknown by far is how long do people remain immune from the virus once they contract it and recover? A number of COVID-19 patients have seen the virus mysteriously resurface after initially contracting it, leading some to question whether antibodies truly do confer permanent and complete immunity on all recovered patients. That's why the WHO has pushed back against immunity passports, much to Bill Gates' chagrin.”

     Here is evidence that Covid-19 immunity may not last, that people will be re-infected by waves of the virus:

“Starting in the fall of 2016 and continuing into 2018, researchers at Columbia University in Manhattan began collecting nasal swabs from 191 children, teachers, and emergency workers, asking them to record when they sneezed or had sore throats. The point was to create a map of common respiratory viruses and their symptoms, and how long people who recovered stayed immune to each one. The research included four coronaviruses, HKU1, NL63, OC42, and C229E, which circulate widely every year but don’t get much attention because they only cause common colds. But now that a new coronavirus in the same broad family, SARS-CoV-2, has the world on lockdown, information about the mild viruses is among our clues to how the pandemic might unfold. What the Columbia researchers now describe in a preliminary report is cause for concern. They found that people frequently got reinfected with the same coronavirus, even in the same year, and sometimes more than once. Over a year and a half, a dozen of the volunteers tested positive two or three times for the same virus, in one case with just four weeks between positive results. That’s a stark difference from the pattern with infections like measles or chicken pox, where people who recover can expect to be immune for life. For the coronaviruses “immunity seems to wane quickly,” says Jeffrey Shaman, who carried out the research with Marta Galanti, a postdoctoral researcher.

Whether covid-19 will follow the same pattern is unknown, but the Columbia results suggest one way that much of the public discussion about the pandemic could be misleading. There is talk of getting “past the peak” and “immunity passports” for those who’ve recovered. At the same time, some hope the infection is more widespread than generally known, and that only a tolerable death total stands between us and high enough levels of population immunity for the virus to stop spreading. All that presumes immunity is long-lived, but what if it is fleeting instead? “What I have been telling everyone—and no one believes me, but it’s true—is we get coronaviruses every winter even though we’re seroconverted,” says Matthew Frieman, who studies the virus family at the University of Maryland. That is, even though most people have previously developed antibodies to them, they get the viruses again. “We really don’t understand whether it is a change in the virus over time or antibodies that don’t protect from infection,” he says.

Critical factor
We’re currently in the pandemic phase. That’s when a new virus, which humans are entirely susceptible to, rockets around the planet. And humanity is still a greenfield for covid-19—as of April 26, there were about three million confirmed cases, or one in 2,500 people on the planet. (Even though the true number of infections is undoubtedly higher, it's still probably only a small fraction of the population.) Takeshi Kasai, the World Health Organization's regional director for the Western Pacific, recently warned that until a vaccine is available, the world should get ready for a “new way of living.”


“A doctor is warning that a new strain of the coronavirus may be emerging. Medical contributor Dr. Janette Nesheiwat raised the possibility in an interview with Fox News after reports from South Korea revealed that some patients, who had recovered from the disease, have tested positive again.

Recovered patients are getting reinfected
In South Korea, which has been lauded for its comprehensive COVID-19 testing strategy, some patients who had been cleared of COVID-19 infection have tested positive again. On Tuesday, the Korean Centers for Disease Control (KCDC) reported that eight more recovered patients have received similar results, bringing the total of “relapsed” patients in the country to 124. But the reinfection cases in South Korea aren’t the only ones being reported. In China’s Guangdong province, health officials have found that 14 percent of recovered patients are retesting positive for the coronavirus. This number includes a patient who died five days after he was discharged and tested negative more than once. In Wuhan, ground zero of the coronavirus pandemic, up to 10 percent of cleared patients are also testing positive for a second time. Meanwhile in Japan, at least one recovered patient — a tour guide from Osaka — has tested positive again after previously testing negative for the coronavirus. The emergence of a new, mutant strain of the coronavirus (SARS-CoV-2) responsible for the outbreak in many countries is just one possible reason why reinfections are happening. Talking to Fox News, Nesheiwat enumerated several other possible reasons that could be causing these cases.

False negatives due to sampling errors
One very likely explanation, according to Nesheiwat, is that the patients had previously gotten “false negative” results. This means that the patients still had the virus in their systems when they got tested, but the test was somehow unable to detect the virus. This could be because the sampling was done incorrectly. “Maybe when whoever was conducting the nasal swab, for example, they didn’t get enough specimen which means they will get a ‘false negative’,” Nesheiwat explained. While the sampling procedure is straightforward — it simply involves inserting a swab deep into a suspected patient’s nose — it’s still easy for clinicians to make mistakes. “It’s not rocket science, but you have to be trained to do it,” said Catherine Klapperich, the director of the Laboratory for Diagnostics and Global Healthcare Technologies at Boston University.

Inaccurate testing also giving positive results
Issues with testing could also be behind the positive results some previously cleared patients have received. According to experts, the PCR test used to detect the presence of the virus is not sensitive enough to distinguish between an active virus and a residual virus. “What many people don’t understand is that PCR tests simply for the virus’ genetic material and it is not an assay for active virus,” said Richard Condit, a molecular biologist and professor emeritus at the University of Florida College of Medicine. While recovering from a viral infection, the body clears what Condit calls the “virus litter,” or the inactive debris of viral cells, from the lungs. There are times, however, when patients cough this litter up into their throats. If they get tested after doing so, the test might mistake this for an active infection when, in fact, it is not.

Dormant viruses resurging
Another possible explanation as to why recovered patients are testing positive again could be that the amount of the virus in their bodies had previously dipped to a point where it could no longer be detected, hence the negative results. However, their viral loads may have spiked again sometime after being discharged, resulting in their current situation. “They could have had low levels [of the virus] that the test wasn’t picking up and started to replicate again,” said Brianne Barker, an associate professor of biology at Drew University in New Jersey. Other viruses are known to reactivate after long periods of latency in the body. One example of this is the varicella zoster virus, the herpesvirus responsible for chickenpox and shingles.

Tracking new strains
If the cause for these strange results some recovered patients are getting is indeed a new mutant strain of SARS-CoV-2, then it isn’t something unprecedented. Scientists have been tracking at least eight different strains of the coronavirus across the globe since the outbreak that started in Wuhan became a massive pandemic. The question now is whether reinfections are indeed happening because of new strain and, more importantly, if this new strain can prevent people from gaining immunity. In South Korea, the KCDC is already hard at work trying to answer these questions. “The virus will be divided and incubated, and genes will of course be analyzed,” said KCDC Deputy Director Kwon Jun-wook. “We are closely looking into possible genetic changes.” The good news is that the coronavirus responsible for the current pandemic does not mutate very fast. According to Kristian Andersen, a professor at Scripps Research, the virus mutates 10 times more slowly than the influenza virus. “The current virus strains are still fundamentally very similar to each other,” Andersen explained. If this is the case, then scientists should be able to catch the emergence of new ones.”

     One of the latest alarming things is the occurrence of covid-19 strokes, affecting younger people now:

“Reports of strokes in the young and middle-aged – not just at Mount Sinai but in many other hospitals in hard-hit communities – are the latest twist in our evolving understanding of the mysteries of covid-19. Even as the virus has infected nearly 2.8 million people worldwide and killed 195,000 as of Friday, its origins, biological mechanisms and weaknesses continue to elude top scientific minds. Once thought to be a pathogen that primarily attacks the lungs, it has turned out to be a much more formidable foe – affecting nearly every major organ system in the body. Until recently, there was little hard data on strokes and covid-19. One report out of Wuhan, China, showed that some hospitalized patients had experienced strokes but many of those were seriously ill and elderly. But the linkage was considered more of “a clinical hunch by a lot of really smart people,” said Sherry H-Y Chou, a University of Pittsburgh neurologist and critical care doctor. Now three large U.S. medical centers are preparing to publish data on the stroke phenomenon for the first time. The numbers are small, only a few dozen per location, but they provide new insights into what the virus does to our bodies. Stroke, a sudden interruption the blood supply, is a complex problem with numerous causes and presentations. It can be caused by heart problems, clogged arteries due to cholesterol, even substance abuse. Mini-strokes often don’t cause permanent damage and can resolve on their own within 24 hours. Bigger ones can be catastrophic. The analyses suggest coronavirus patients are mostly experiencing the deadliest type of stroke. Known as large vessel occlusions or LVOs, they can obliterate large parts of the brain responsible for movement, speech and decision-making in one blow because they are in the main blood-supplying arteries. Many researchers suspect strokes in novel coronavirus patients may be a direct consequence of blood problems that are producing clots all over some people’s bodies. Clots that form on vessel walls fly upward so one that started in the calves might migrate to the lungs, causing a blockage called a pulmonary embolism that arrests breathing – a known cause of death in covid-19 patients. Clots in or near the heart might lead to a heart attack, another common cause of death. Anything above that would likely go to the brain, leading to a stroke.”

     Overall, even given the masses of uncertainties around the coronavirus issue, there are continuing developments which in themselves pose a threat to normal life, whatever way the politics of this goes. We need to be ever vigilant.



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Wednesday, 12 June 2024

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