The popular “vaccine” concept is that it is a vaccine that can immunize you against pathogens-if not for life, at least for a long time. Based on this principle, most of the world’s hopes for returning to normal conditions before the pandemic rest on the new coronavirus vaccine, which is the cause of COVID-19.
However, it turns out that common concepts about how vaccines work are not entirely accurate. The reason is related to two concepts-“transient immunity” and “persistent immunity”
At present, we are not sure which category the new coronavirus belongs to, although more and more evidence shows that immunity to it will not last. Indeed, many cases have been infected with the virus multiple times within a few months. Although they may be outliers of a poor immune system, more cases of reinfection have not.
But there is another problem: compared to infection, vaccines can actually confer different types of immunity-for example, long-term rather than short-term.
From the perspective of global public health, you can see how to return to normalcy depends on our understanding of coronavirus immunity. In other words, can coronavirus immunity last a lifetime, one year or just a few months? Do those who are infected already need the vaccine, or are they immune?
Science keeps changing this to no avail, and monthly scientific research draws slightly different conclusions. As Sharon previously reported, current data and research show that immunity is not as lifelong as measles. However, because it is a new virus, it is difficult to know how long the immunity will last, but this is all that scientists currently know.
First, let’s talk about immunity
The human body can resist viral infections in many ways. Dr. Charles Chiu, a professor of infectious diseases at the University of California, San Francisco, pointed out three specific aspects to Sharon: passive immunity, neutralizing antibody immunity and active immunity.
“The idea is that for any viral infection, including the new SARS-CoV-2 infection, patients with a complete or healthy immune system will have an immune response,” the University of California, San Francisco told Salon. He said this is called “passive immunity.”
“This is really antibody-centric,” Chiu said. “The idea is that B cells are white blood cells in the blood that react to viruses and produce antibodies.”
Chiu says these antibodies can be used in one of two different ways. One method is that the antibody will be “neutralized” and bind to the virus. Therefore, as the name suggests, these antibodies will “neutralize” or inactivate the coronavirus. This is called “neutralizing antibody immunity”.
Chiu explained: “The idea is that if you have immunity, the next time you re-infect, these antibodies will already circulate and exist in the blood, and they will neutralize the virus immediately.” “Therefore, you will reduce the possibility of infection. , Otherwise you will not be infected again.”
However, not all antibodies are neutralized. Chiu pointed out that HIV (Human Immunodeficiency Virus) is a virus and the antibodies it produces will not be neutralized.
Chiu pointed out: “You will produce antibodies against viral infections, but you will not necessarily produce neutralizing antibodies to prevent you from being infected again.”
Then there is “active immunity”, which is another type of immune response that is mediated by another type of white blood cell (T cell).
“T cells will respond positively [the virus]Chiu said: “They are memory T cells, they will remember when you were previously infected. If exposed again, these T cells will enter and help prevent reinfection.”
Understanding “persistent” and “transient” immunity
Immunologists are trying to find out whether the coronavirus infection has Long-lasting immunity Either Transient immunity. These terms refer to the intensity and duration of the type of immunity.For example, if the antibody produced due to a virus infection is durable, Which means that immunity is lasting.If they are Short-lived, Which means they will only last for a short while.
As mentioned above, more and more evidence shows that immunity to the new coronavirus is short-lived. But how short? We don’t know, but there is more evidence every week. In September, researchers published a study in the scientific journal “Natural Medicine”, which showed that according to four different seasonal coronaviruses, people infected with the new type of coronavirus and then become immune may remain in this state for a long time. Up to twelve months.
However, as Chiu pointed out, there are some differences between the new coronavirus (SARS-CoV-2) and seasonal coronaviruses. One is that they exist longer, which means they are more diverse, because they have more time to mutate.
Qiu said: “It hasn’t had time to mutate widely and become very divergent.” “This means that vaccines that specifically target SARS-CoV-2 are more likely to be durable; they are more likely to last longer and more Effectively longer, perhaps because the difference between this particular strain is smaller compared to other seasonal coronaviruses.”
What does this mean for COVID-19?
There have been several studies on antibodies and SARS-CoV-2. In a study, researchers tracked the condition of COVID-19 patients and found that their antibody levels peaked after the onset of symptoms and then began to decline. For some study participants, antibodies were almost undetectable for three months. A recent study of British patients showed similar trends. However, as explained in an article in the journal Nature, it may require only a small amount of antibodies to prevent re-infection and fight the coronavirus again.
However, the most important thing is that the vaccine can confer different types of immunity compared to the actual virus infection.Indeed, immunologists point out that vaccines can durable Immunity, even if the natural response is Short-lived.
Shane Crotty, a virologist at the La Jolla Institute for Immunology, told the New York Times: “The vaccine does not have to imitate or reflect natural infections.”
Immunologists have always used human papillomavirus (HPV) as an example. This virus has a poor immune response and weak antibodies, but the vaccine immune response has lasted for at least ten years.
Considering that the coronavirus may have a short-term immunity, this will make it more difficult for countries and cities to achieve cattle immunity by spreading the virus.
Qiu said: “It actually depends on its transient nature and how quickly we can actually inoculate a sufficient proportion of the population to generate herd immunity.” Multiple doses are effective. “We have now questioned the use of the flu vaccine, and there is no reason to think it will be different.”
This means that the best option for humans to gain lasting immunity is still through vaccines. A group of researchers published in The Lancet said that the strategy of relying on waiting for the immunization of the herd is “defective.”
The researchers wrote: “There is no evidence that natural infection has long-lasting protective immunity to SARS-CoV-2, and local transmission caused by weakened immunity will threaten vulnerable people indefinitely,” the researchers wrote. “This strategy will not end the COVID-19 pandemic, but it will lead to recurrent epidemics, just like many infectious diseases before the vaccine.”
In other words, political leaders who hope to defeat the virus in achieving herd immunity will not only fail, but they will unnecessarily kill their citizens in the process. Both President Donald Trump and British Prime Minister Boris Johnson touted the strategy of achieving herd immunization by deliberately failing to take public health actions so that the virus can spread through citizens.
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