- For those recovering from COVID-19, immunity to the virus can last at least 8 months and perhaps longer, research shows.
- Immunity can occur naturally after developing COVID-19 or receiving the vaccine against COVID-19.
- Because the duration of immunity after developing COVID-19 or receiving the vaccine is unknown, it is necessary to practice physical or social distancing and wear a mask to stop the spread.
Whether you have recovered from COVID-19, whether you have received the vaccine, or not, understanding immunity and how long it can last can help give you an important insight into how you can safely interact with others during the pandemic.
First, it helps to know what immunity means.
There are two types of immunity: natural and vaccine-induced.
After a person acquires a virus, the immune system retains a memory of it.
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The components of immunity protection:
- Antibodies are proteins that circulate in the blood and recognize foreign substances such as viruses and neutralize them.
- Helper T cells help recognize pathogens.
- Killer T cells kill pathogens.
- B cells make new antibodies when the body needs them.
People recovering from COVID-19 have been shown to have these four components. However, the details of what this means for the immune response and how long the immunity lasts are unclear.
According to Lauren Rodda, PhD, a postdoctoral researcher in immunology at the University of Washington School of Medicine, we don’t know for sure if people are immune to reinfection simply because not enough studies have been done yet.
“This would require tracking the re-exposure of a significant number of people and determining if they get sick,” Rodda told Healthline.
However, knowledge in this area continues to grow as new studies are conducted.
More recently, a study published in the journal Science found that immunity can last up to 8 months.
According to Shane Crotty, PhD, a professor at the La Jolla Institute of Immunology in California who led the study, his team measured the four components of immune memory in nearly 200 people who had been exposed to SARS-CoV -2, which causes COVID-19 and recovers.
The researchers found that all four factors persisted for at least 8 months after the virus infection.
This is important because this demonstrates that the body can “remember” SARS-CoV-2. If the virus is found again, memory B cells can quickly prepare and produce antibodies to fight it.
Those who have recovered from COVID-19 could have immunity for months or perhaps even years, the authors said.
Prior to the latter study, Rodda said his research team and others were working, proving that the antibodies were kept for at least 3 months.
In the study of his team, in particular, it was shown that this occurs even in people who have mild symptoms.
His study also suggested that immunity could last much longer.
In a different study published in The New England Journal of Medicine, researchers in Iceland studied 1,107 people who had recovered from COVID-19 and tested positive for antibodies.
Over a 4-month period, they found that those COVID-19 antibodies did not decrease.
A study published in the journal Immunity found that people who recover even from mild cases of COVID-19 produce antibodies for at least 5 to 7 months and could last much longer.
His team has tested nearly 30,000 people in Arizona since April 30, 2020, shortly after a blood test for the new coronavirus was developed.
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The two vaccines require two shots a few weeks apart to get complete protection.
Once you have full protection against the vaccine, your body is left with a supply of T cells and B cells that will remember how to fight the virus in the future, just as they do with natural immunity.
However, the body takes a few weeks to produce T cells and B cells after vaccination. During this time, it is possible to acquire the virus that causes COVID-19 until the body can provide protection.
In a Questions and Answers with the World Health Organization (WHO),
Researchers still don’t know how long vaccine immunity lasts and whether follow-up shots will be needed, especially to protect themselves from new ones.
Studies are underway.
The Centers for Disease Control and Prevention (CDC) states that “almost all individuals with immune capacity will develop an immune response after SARS-CoV-2 infection” and that in some people antibodies can be detected during the first week of the onset of the disease. .
However, there are different antibodies
For example, some tests look for antibodies that recognize the nucleocapsid protein, which is found in the coronavirus, while others look for antibodies that protect against the coronavirus ear protein (these antibodies are triggered by the Modern vaccine).
Although a positive antibody test shows that you have the virus that causes COVID-19 or the vaccine, it still does not give a clear understanding of your immunity to the virus.
Dr. Steven Sperber, interim head of the infectious disease division at Hackensack University Medical Center, said he does not know if having a positive antibody test means he is immune to the virus.
He explained that for some infections, antibodies could protect against reinfection.
For others, it may not prevent reinfection, but the symptoms may be milder.
In other cases, the antibodies may not provide any protection.
In addition, some test results may be “false positives.” This happens when a person has been exposed to a similar virus detected by the test, but these antibodies do not protect the new coronavirus.
Finally, Sperber said, we don’t know how long any protection can last.
Although virus infection and vaccination may provide some immunity, reinfection is not yet fully understood.
There are ongoing studies to understand:
- the probability of reinfection
- how often reinfection occurs
- how long after the first infection reinfection can occur
- how severe are cases of reinfection
- who could have a higher risk of reinfection
- what reinfection means for a person’s immunity
- if a person is able to transmit SARS-CoV-2 to other people when they become infected again
Until further notice, in addition to getting vaccinated, the CDC recommends wearing masks, physically distancing yourself, and washing your hands frequently to help.
Additional reports from Nancy Schimelpfening.