- For those who recover from COVID-19, immunity to the virus can last about 3 months to 5 years, research shows.
- Immunity can occur naturally after developing COVID-19 or from getting the COVID-19 vaccination.
- Because the length of immunity after developing COVID-19 or getting the vaccine is unknown, practicing physical or social distancing and wearing a mask need to continue to stop the transmission.
Whether you’ve recovered from COVID-19, received the vaccine, or neither, understanding immunity and how long it lasts can help give you important insight into how you can 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.
The components of immunity protection include:
- Antibodies are proteins that circulate in the blood and recognize foreign substances like viruses and neutralize them.
- Helper T cells help to recognize pathogens.
- Killer T cells kill pathogens.
- B cells make new antibodies when the body needs them.
People who recover from COVID-19 have been found to have all four of these components. However, specifics about what this means for the immune response and how long immunity lasts are not clear.
Dr. William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center, said it’s not known exactly how long the protection after natural infection will last and how durable that protection will be against a variety of different variants.
“There are some people who have the notion that after you’ve gotten natural infection, you will be permanently protected against COVID-19 as if this were measles. Unfortunately, the two viruses are very, very different. The coronavirus protection wanes naturally after a period of time,” Schaffner told Healthline.
Because COVID-19 is caused by a coronavirus, which the type of virus the common cold is also caused by, he said researchers have an understanding of how other coronaviruses behave, which may help understand immunity for COVID-19.
“We all know we can get repeated common colds, and the studies on those viruses indicate that their protection begins to wane after about a year, and of course we can get reinfected down the road,” he said.
An October 2021 study by the Yale School of Public Health that was published in The Lancet Microbe reported that unvaccinated people should have immunity against reinfection for 3 to 61 months after they get COVID-19, if their community is still experiencing infections from the virus.
The researchers determined their conclusions based on analysis of previously published data on viruses that are similar to SARS-CoV-2, which causes COVID-19.
They concluded that re-acquiring the virus that causes COVID-19 is similar to that of getting the viral infection that causes the common cold from year to year. They note, however, that at this time, during the pandemic, COVID-19 has proven to be much more deadly.
“We know [acquiring] the coronaviruses do not provide long term protection. We don’t expect that the protection from natural infection from COVID is going to be long-term. But we still need more data on this,” said Schaffner.
An older study published in the journal Science found that immunity can last for as long as 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 almost 200 people who had been exposed to SARS-CoV-2 and recovered.
The researchers found that the four factors persisted for at least 8 months following infection with the virus.
This is important because this shows that the body can “remember” SARS-CoV-2. If it encounters the virus again, the memory B cells can quickly gear up and produce antibodies to fight it.
Before this study, Lauren Rodda, PhD, a senior postdoctoral fellow in immunology at the University of Washington School of Medicine, said work had been done by her research team and others, showing that antibodies are maintained for at least 3 months.
In her team’s
Their 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 the antibodies.
Over a 4-month period, they found that those COVID-19 antibodies did not decline.
Their team has tested nearly 30,000 people in Arizona since April 30, 2020, shortly after a blood test for the new coronavirus was developed.
The Centers for Disease Control and Prevention (CDC) reported that
For instance, in clinical trials, the Moderna vaccine was about 94 percent effective at preventing COVID-19 and the Pfizer-BioNTech vaccine was 95 percent effective.
Real-world data also shows that Pfizer and Moderna vaccines are effective at reducing the risk of COVID-19, including severe illness, by
While the Johnson & Johnson vaccine was
“We know that after you’ve had natural infection, and then get vaccinated, you get a terrific boost in your antibody levels. And very high antibody levels traditionally have been associated with longer duration of protection. And in the laboratory, it looks as [if] those antibodies also provide a better protection against variants,” said Schaffner.
While the Pfizer and Moderna vaccines require two shots a few weeks apart to get full protection, Johnson & Johnson only requires one shot.
Once you have full vaccine protection, your body is left with a supply of T cells as well as B cells that will remember how to fight the virus in the future, just like 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 this time, it’s possible to acquire the virus that causes COVID-19 until your body can provide protection.
In a Q&A with the World Health Organization (WHO),
While the vaccines are explicitly designed to create a large immune response, Schaffner said that they are not 100 percent effective, and therefore the need for a booster shot may become standard like it is annually for the flu, especially to protect against
In fact, on September 22, 2021, the Food and Drug Administration (FDA), amended the emergency use authorization (EUA) for the Pfizer-BioNTech COVID-19 vaccine to allow for use of a
On October 20, the
Additionally, the FDA authorized that each of the available COVID-19 vaccine boosters can be mixed and matched in eligible people following completion of primary vaccination.
Those who are eligible for all the boosters include people ages:
- 65 years and older
- 18 through 64 years who are at high risk of severe COVID-19
- 18 through 64 years whose frequent institutional or occupational exposure to SARS-CoV-2 puts them at high risk of serious complications of COVID-19 including severe COVID-19.
The FDA took various data into consideration when it authorized the use of boosters.
On May 10, 2021, the FDA expanded the emergency use authorization (EUA) for the Pfizer-BioNTech COVID-19 vaccine to include kids ages 12 through 15 years old.
In October 2021, Pfizer and BioNTech requested that the FDA authorize emergency use of its vaccine for 5- to 11-year-olds.
“We need to extend that protection to a much larger proportion across the country. Children are less apt to get serious disease, but they can get serious disease. There have been over 300 children of all ages that have died of COVID since the beginning of COVID, and for those families, it’s 100 percent,” said Schaffner.
He added that the Delta variant makes children more apt to transmit the virus.
“Now Delta has come on the scene and is now the dominant virus and much more contagious than the original strain, and it’s clearly moving into the pediatric population now, so it’s behavior was different than the original strain, and that gives even more reason to vaccinate children,” he said.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub and follow our live updates page for the most recent information on the COVID-19 pandemic.
Additional reporting by Nancy Schimelpfening.