Every time a new virus enters the human population, one of the first questions asked by immunologists is how the body’s immune system reacts to it when the immune system clears it of the body. For certain viruses, getting vaccinated once (or once vaccinated) means you now have lifelong immunity; in other cases, the immune system seems to forget how to defend against them after a short period of time.
Now, for the good news: While some experts previously feared that a coronavirus vaccine might only provide short-term immunity, this may not be true. Recently there has been a floor of promising research that signals that those recovering from a coronavirus infection will have lasting immunity. UThe immune response of the human body is the key to returning to any sense of normalcy in our world, and has implications for public health behavior and vaccine development.
According to one of the new studies, which has not yet been peer-reviewed and was posted on MedRxiv over the weekend, researchers at the University of Arizona conclude that “immunity lasts for at least several months after SARS-CoV-2 infection.” Specifically, the study says that a previously infected person is at least three months immune to the coronavirus, even after a mild infection; although researchers say this is a conservative prediction based on lack of long-term human health data for the emerging virus.
The conclusion is conflicting with previous reports that suggested immunity was transient, meaning that it only lasted a short time.
Deepta Bhattacharya, associate professor of immunobiology at the University of Arizona and co-author of the paper, told Salon in an interview that he and his colleagues came to their conclusion after measuring antibodies and examining how long they were produced in COVID-19 patients.
“In most viral infections that are obvious, we call these acute viral infections, early antibodies that are made and then put down, and usually what happens is that after that initial infection phase they become a flat and stable point. beat, “said Bhattacharya. “We tried to see if that happens in COVID-19 survival or not.”
It turns out there is a similar anti-antibody build-up for other acute viral infections. The study looked at 5,882 volunteers, including asymptomatic individuals. Bhattacharya told Salon that the researchers in the study noted that the antibodies are present for at least three months, as that is the longest time frame they have measured, but it could be longer.
“It is not that the immunities disappear suddenly after three months. We can say that it is at least three months,” he said. “Now if I had to make a prediction based on the first SARS-CoV-1 coronavirus, I think it would probably take years.”
Bhattacharya said this research is stimulating in terms of vaccine development.
“I think from a fax point of view, it basically sets the parameters of what we know is possible,” Bhattacharya added. “That does not necessarily mean that a vaccine will work perfectly and it does not necessarily mean that every vaccine that is there will be very effective, but at least it tells us that this is a very achievable goal, that this virus can be eradicated and that you can generate immunity against, “he said.
According to another study, currently viewed in the journal Nature, researchers concluded that mild COVID-19 infections traditionally “display hallmarks associated with antiviral protection immunity.”
We found that recovering individuals developed SARS-CoV-2-specific IgG antibody and neutralized plasma, as well as virus-specific B and T cells that not only persisted but in some cases increased numerically in three months after symptom onset. , “the researchers wrote.
However, researchers will not know for sure if reinfection is possible for a longer period of time until there is more evidence of people being exposed to the virus a second time, to observe if they are able to keep it.
After being infected with a virus, the human body makes proteins called antibodies that can detect and attack that virus as it re-enters the body. This is how the body develops immunity to an infection. How long that immunity lasts depends on the type of infection: once, for example, someone is infected with measles, they are immune for the rest of their lives. But when it comes to seasonal coronaviruses, it’s a little more complicated. In front of SARS en MERS, this line of defense has been present in survivors, according to separate studies, for about two years. Antibodies, which were studied in both papers, do not last forever because they are not living cells. They cannot replace themselves and they eventually disappear from the bloodstream.
Dean Blumberg, head of pediatric infectious diseases and associate professor in the Department of Pediatrics at the University of California, Davis, told Salon that a long-term follow-up is needed to truly understand immunity and how long it takes due to antibodies.
“You can measure the immune response, but you do not know for sure that it protects against infection until you do the studies,” Blumberg said. “We do not know how long people who have been infected, how long they will be protected from future infection, whether it is now a month, similar to the other coronaviruses or maybe it is longer.”
Because the immune system responds differently to this coronavirus compared to others, and because the most serious cases occur when the immune system overreacts, Blumberg said it is possible that there may be a stronger immune response in those who have have restored.
“If you look at what happens to other coronaviruses, less pathogenic, it seems like immunity after infections lasts a few months and then you can get infected again, so that’s depressing,” Blumberg said. “But this is not exactly the same – we know it’s different.”
