- For those recovering from COVID-19, immunity to the virus can last at least 8 months or more, research shows.
- Immunity can occur naturally after the development of COVID-19 or vaccination against COVID-19.
- As the duration of immunity after developing COVID-19 or receiving the vaccine is unknown, the practice of physical or social detachment and the use of a mask must continue to stop the spread.
If you recovered from COVID-19, received the vaccine, or neither, understanding immunity and how long it lasts can help provide important information on how to interact safely 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 to recognize pathogens.
- Killer T cells kill pathogens.
- B cells produce new antibodies when the body needs them.
People who recover from COVID-19 have been found to have all four of these components. However, the details of what this means for the immune response and how long immunity lasts are unclear.
According to Lauren Rodda, PhD, a senior postdoctoral researcher in immunology at the University of Washington School of Medicine, we are not sure whether people are immune to reinfection simply because not enough studies have been done.
“This would require tracking the reexposure of a significant number of people and determining whether they will be sick,” Rodda told Healthline.
Knowledge in this area continues to grow, however, as new studies are carried out.
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 for Immunology in California who co-led the study, his team measured all four components of immune memory in nearly 200 people who were exposed to SARS-CoV-2, which causes COVID-19 and recovered.
The researchers found that the four factors persisted for at least 8 months after infection with the virus.
This is important because it shows that the body can “remember” SARS-CoV-2. If it finds the virus again, memory B cells can quickly equip and produce antibodies to fight it.
Those who recovered from COVID-19 may have immunity for months or perhaps years, the authors said.
Prior to this latest study, Rodda said the work had been done by his research team and others, showing that antibodies are maintained for at least 3 months.
In his team’s study, in particular, it was shown that this occurs even in people who have mild symptoms.
The 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 recovered from COVID-19 and tested positive for the antibodies.
Over a period of 4 months, they found that the COVID-19 antibodies did not decrease.
A study published in the journal Immunity found that people who recover from even mild cases of COVID-19 produce antibodies for at least 5 to 7 months and can last much longer.
His team has tested about 30,000 people in Arizona since April 30, 2020, just after a blood test for the new coronavirus was developed.
Currently, the
Both
Both vaccines require two injections a few weeks apart to obtain full protection.
Once you have full protection from the vaccine, your body is left with a supply of T and B cells that will remember how to fight the virus in the future, just as they do with natural immunity.
However, it usually takes a few weeks for the body to produce T cells and B cells after vaccination. During that time, it is possible to acquire the virus that causes COVID-19 until your body can provide protection.
In a question and answer session with the World Health Organization (WHO),
Researchers still do not know how long vaccine immunity lasts and whether follow-up vaccines will be needed, especially to protect against new ones.
Studies are ongoing.
The Centers for Disease Control and Prevention (CDC) claim that “almost all immunocompetent individuals will develop an immune response after SARS-CoV-2 infection” and that in some people, antibodies can be detected within the first week of onset 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 spike protein (these antibodies are triggered by the Modern vaccine).
Although a positive antibody test shows that you have had 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, acting chief of the infectious disease division at Hackensack University Medical Center, said he does not know whether having a positive antibody test means that you are immune to the virus.
He explained that for some infections, antibodies can protect against reinfection.
For others, they may not prevent reinfection, but the symptoms may be milder.
In still other cases, antibodies may not provide any protection.
In addition, some test results can be “false positives”. This occurs when a person has been exposed to a similar virus detected by the test, but these antibodies do not protect the new coronavirus.
Finally, said Sperber, we don’t know how long any protection can last.
Although virus infection and vaccination may provide some immunity, it is not yet fully understood about reinfection.
Studies are underway to understand:
- the likelihood of reinfection
- how often reinfection occurs
- how soon after the first infection reinfection can occur
- how serious are the cases of reinfection
- who may be most at risk of reinfection
- what reinfection means for a person’s immunity
- whether a person is able to transmit SARS-CoV-2 to others when reinfected
Until more is known, in addition to being vaccinated, the CDC recommends the use of masks, physical distance and hand washing frequently to help
Additional reporting by Nancy Schimelpfening.