- Scientists are getting closer to declaring immunity to coronavirus after infection or after immunization with a potential vaccine.
- A new series of studies shows that the immune system has a strong response to the pathogen, even in asymptomatic or mild cases.
- The researchers can not definitively determine how long COVID-19 immunity will last, but they can prove that even people who do not show detective levels of antibodies after the primary infection will be protected in the months that follow.
The novel coronavirus is simply too new for scientists to figure out how long immunity can last. This is an important detail that will help with immunization protocols once vaccines are available, as well as public health campaigns to contain outbreaks and reduce infection rates. The longer the immunity lasts, the easier and faster the world will achieve herd immunity through a combination of vaccinations and direct infections. And once a large enough number of people are immune to COVID-19, the transmission rate will drop significantly. The virus will continue to roam the planet just like the flu viruses, and it will also fight new outbreaks. But the pandemic can still be overcome and future COVID-19 outbreaks will not be so bleak.
New studies have given us the good news about immunity we currently need, showing that the immune system has what it takes to fight reinfection, even after antibodies disappear from the system. These studies also show that the immune system has a strong defense in asymptomatic and mild cases, although they may not provide the one immune response that we all want the most.
Researchers have succeeded in proving that infection with the virus will lead to temporary immunity in monkeys. Fax research has shown that several experimental drugs can elicit immune responses that are equal to or better than the immune system’s response to actual infection. But when scientists studied the virus, some bad news about immunity crept in. Some experts believe that COVID-19 protection could last between six and 12 months, as is the case with resistance to human coronaviruses that cause the common cold. Others discovered that neutralizing antibodies disappear into the bloodstream within three months.
Then the good news comes in. Immune protection does not disappear once antibodies are gone. T cells retain the memory of the new coronavirus and can produce a new wave of anti-antibodies upon reinfection. Then we heard that T cells trained during common colds to recognize other human coronaviruses could also launch a defense against the new strain.
A few days ago, the CDC quietly updated its COVID-19 quarantine guidelines with new information stating that coronavirus immunity is likely to last at least three months for people who are infected. This is the first time that a health authority has somehow quantified COVID-19 immunity. It may seem like bad news, but as we have explained, the CDC’s findings are not definitive. This is just an indication that the CDC is sure that reinfection is not possible within three months after the first infection. Some people have tested positive again weeks after the recovery, but all the data we have so far indicated that this is not up to date. Traces of the virus may still be present in the body in a significant enough quantity to return a positive PCR test, but those patients are not contagious.
This brings us to a new set of research articles indicating that the human body has what it takes to deliver lasting immunity, even after a mild case of COVID-19. The New York Times has highlighted a number of new studies addressing COVID-19 immunity, including research papers that have not yet been peer-reviewed.
“Things really work out the way they should,” said University of Arizona immunologist Deepta Bhattacharya. The Times. The researcher found that “the antibodies decrease, but they establish themselves in what appears to be a stable nadir,” which is about three months after the onset of symptoms. “The response looks perfectly sustainable.”
This is an indication that even though most of the antibodies have disappeared from the bloodstream, some of them still pull. The B cells that produce them can patrol the body or return to bone marrow. It is up to the T cells to recognize the pathogen upon reinfection and activate the antibody-producing B cells that will re-establish the fight.
“This is exactly what you should be hoping for,” said immunologist Marion Pepper of the University of Washington. “All pieces are there to have a fully protective immune response.” Like Bhattacharya, Pepper’s team found that antibodies hang at low levels, which is evidence that B cells are still up to date. Pepper and her team collected B-cell samples from patients recovering from mild COVID-19 cases and grew them in the lab.
Another paper published in Sel proved that the body mounts a robust T-cell response in COVID-19 survivors who were asymptomatic or had a mild case. The scientists took T-cell samples long after symptoms disappeared and exposed them to the new coronavirus in the lab. The T cells were still able to deliver the correct signals and cloned themselves to mount a defense against the virus.
Researchers from Canada searched for coronavirus antibodies in saliva and found that the Y-shaped proteins could survive for more than three months at the site of infection, such as mouth, or nose. The researchers correlated the number of saliva antibodies with serum antibodies and concluded that the former could provide COVID-19 immunity.
None of these studies can tell us how long the immune response lasts, but they do prove that even people who do not have a bad COVID-19 case will still have a lasting immune response. This is promising news for vaccines and herd immunity, given that most COVID-19 patients out there develop mild COVID-19 infections, and many are asymptomatic. Previous studies have shown that antibody screening can yield false-negative results for asymptomatic patients rather than people who have had only moderate cases. The new research documents indicate that the presence of detective antibodies does not tell the full COVID-19 immunity story.
Some of these studies have not been tested and more research is needed on the issue of COVID-19 immunity, but this is good news. Proving that the body is developing a strong immune response to COVID-19 despite symptoms is only the first step. Researchers will also need to prove that the immune response actually works on reinfection – or that vaccines can actually block the infection.
Chris Smith began writing about gadgets as a hobby, and before he knew it, he was sharing his views on tech things with readers all over the world. Every time he does not write about gadgets, he manages to get away with it, even though he tries desperately. But that’s not necessarily a bad thing.
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