How Long Do COVID Antibodies Stay In Your System?

Our immune system is like a defense fortress — always on guard and ready to attack invaders. When we come into contact with bacteria or viruses, our bodies recognize them as harmful and respond. Fevers, coughing, and sneezing are all ways our body tries to kill or get rid of germs while our immune system makes antibodies against the infection.

Antibodies are proteins that some of our immune cells create to help fight off infections. These antibodies are unique to the germs that can cause an infection. Our bodies develop higher antibody levels after being sick or getting a vaccine.

Here, we’ll explain how our immune system makes antibodies, how long it takes to develop antibodies, and how long COVID-19 immunity lasts for.

What are antibodies?

Antibodies are the result of our immune system fighting an infection or receiving a vaccine. They are unique proteins that help our immune cells (called white blood cells) more effectively kill bacteria or viruses. But making them is a process that takes time.

There are three main types of white blood cells that help our immune systems protect us:

• Macrophages: These cells will attack and break apart viruses and bacteria. What they leave behind when they’re done are known as antigens. These are portions of bacteria and viruses that antibodies learn to target. 

• B-lymphocytes: These cells, also known as “B cells,” make antibodies to attack the antigens that were left behind. The antibodies are unique for that particular virus or bacteria. If the same infection gets into your body again, your B cells will make these unique antibodies and aim to kill the infection right away.

• T-lymphocytes: These cells — known as “T cells” — are responsible for taking care of cells that have been infected by a virus or bacteria. They will kill these damaged cells and the infection inside of them. After the germs are gone, most T cells will be destroyed. The few left behind are known as memory cells. They’re responsible for remembering the virus or bacteria should we come into contact with it again.

The term “active immunity” means our immune system has successfully made antibodies and has learned to fight certain bacteria or viruses. But there are two different types of active immunity — natural immunity and vaccine-induced immunity.

• Natural immunity is when you make antibodies and memory cells after you recover from an infection. 

• Vaccine-induced immunity is when you make antibodies and memory cells after receiving a vaccine. While your body learns how to kill the germs either way, a vaccine will teach your immune system to fight an infection without getting you sick.

How long does natural immunity last after a COVID-19 infection?

Early on, researchers thought that natural immunity to COVID-19 only lasted for about 2 to 3 months before fading. As the pandemic continued, experts started finding evidence that natural immunity could last for longer after infection. But along came Omicron and its subvariants — and that’s changed everything.

The Omicron variant is very different from the original and Delta strains of SARS-CoV-2 (the virus that causes COVID-19) that made many people sick during 2020 and 2021. One big difference is its ability to go undetected by our antibodies, even if we previously had COVID-19. This is called immune escape, or immune evasion.

This immune escape quality is concerning. It means the chance of you getting sick with COVID-19 again is higher with an Omicron subvariant. 

Can you get sick with COVID back-to-back?

Even if you have recently been infected with BA.4 or BA.5, there is evidence that these latest variants leave almost no mark on the immune system. This means that infection with BA.4 and BA.5 does not provide a natural boost to immunity and you can get sick with COVID-19 back-to-back. 

In fact, a study from the U.K. found that only about 19% of people who had an earlier infection from COVID-19 were protected from getting sick from the Omicron variant. In other words, over 80% didn’t gain immunity to the Omicron variant after being infected in the past.

It’s hard to say how long protection lasts after getting sick from the Omicron variant. The way things are looking, it would seem that getting sick with a newer subvariant doesn’t provide much protection at all against Omicron subvariants. 

This strain of COVID-19 is also still fairly new, so long-term immunity studies won’t be available for some time. While experts will continue to study this, we don’t know how long natural immunity to the COVID-19 Omicron variant lasts.

How long does vaccine-induced immunity last?

Vaccine immunity to COVID is a slightly different thing. Even before Omicron and its subvariants, there was concern about how long the protection from COVID-19 vaccines would last. 

Earlier research from the CDC suggested that protection from the Pfizer and Moderna COVID-19 vaccines could start to fade around 4 months after a booster dose. Protection against COVID-19 hospital stays seemed to drop from 91% soon after receiving a booster dose to 78% at the 4-month mark.

With breakthrough infections (getting sick even after being fully vaccinated) becoming more commonplace, the FDA and CDC recommends adults and children ages 12 and older receive a vaccine booster (or a 2nd booster if aged 50 and over). during fall 2021. 

But, as we’ve seen recently, even with booster doses, breakthrough infections from newer Omicron subvariants are possible.

Experts still believe that vaccination reduces the risk of severe illness, hospitalization and death from BA.4 and BA.5. So, while you may test positive for a COVID infection, and you may even feel unwell with symptoms, you’re less likely to become seriously unwell from COVID if you’ve been vaccinated and boosted. 

What’s less clear is the longer-term impact of these latest waves of infection on long-term health, including long COVID, in vaccinated people. 

The CDC noted that this time frame is similar for people who’ve only received two doses of Pfizer’s or Moderna’s mRNA vaccines. Protection against COVID-19 hospital stays falls from 71% two months after the second dose to 54% after 5 months. 

The important thing to note is that a third dose of an mRNA vaccine offers much greater protection than two doses. However, this fading protection has experts around the world researching whether a fourth dose will be needed.

The good news is, researchers found that people’s T cells respond effectively to the Omicron variant — even 6 months after their last vaccine dose. So while your immune system might not prevent infection from the Omicron variant, it will likely protect you from becoming very sick.

How long does it take to develop COVID-19 antibodies?

As mentioned above, there are two different ways your immune system can learn to make antibodies and memory cells for a virus or bacteria: natural immunity and vaccine-induced immunity. 

Both are effective ways to develop immunity. However, vaccine-induced immunity allows your immune system to learn how to protect you without actually getting sick.

Natural immunity

If you get sick with COVID-19, your immune system will make antibodies days to weeks after you were infected. However, this does not mean you will feel 100% better. Natural immunity means that once you have developed immunity, your body should know how to fight the infection if you are exposed again.

As mentioned above, reinfection is possible and more likely to happen with Omicron subvariants. This is why it’s suggested that people get vaccinated and boosted even if they were previously sick with COVID-19. It’s also recommended to continue wearing masks in crowded, high-risk areas after you’ve recovered.

Vaccine-induced immunity

It takes a couple of weeks for your body to build immunity after vaccination. For that reason, you are not considered fully protected until 2 weeks after your final shot or booster. This means 2 weeks (14 days) after getting your second shot of Pfizer-BioNTech or Moderna or 2 weeks after the Johnson & Johnson shot.  Regardless of which vaccine you get, though, there are two important things to remember:

You need to have both shots of the two-dose vaccines to be fully protected. And, if 5 months or more have passed since the second mRNA shot, or 2 months since the Johnson & Johnson shot, get a booster dose.

And, while it’s still possible to get sick with COVID-19 after getting vaccinated, your risk of severe illness and death is still lower than if you were unvaccinated.

Does testing positive for COVID-19 antibodies mean I am immune to COVID-19? 

Unfortunately, no. Experts don’t know whether a positive COVID-19 antibody test means that a person is or will become immune to the COVID-19 virus. As mentioned above, many people don’t become immune after being sick with an Omicron subvariant. People may still make antibodies while they’re sick. But because of immune evasion, those antibodies may not be able to pick up on another Omicron infection in future. 

As a result, people should not rely on antibody testing to decide whether or not to get vaccinated. It is recommended to get a COVID-19 vaccine if you’re eligible, even if you’ve previously been sick and recovered.

How do I know if I’ve had COVID-19?

In April 2022, the CDC reported that about 60% of Americans have been infected with COVID-19. They also estimated that 75% of U.S. children have previously had the virus. So, there’s a good chance that you’ve had COVID-19, even if you didn’t have symptoms.

If you’re curious to find out if you’ve been infected, there are ways to find out. There’s a blood test that can look at your T-cells. This test — called a T-cell receptor (TCR) assay — can tell if your body fought a COVID-19 infection. A TCR assay can also detect if you had COVID-19 but had no symptoms.

However, the makers of T-Detect (the only FDA-authorized COVID-19 TCR assay) have stated that they don’t know if being vaccinated would affect the test’s accuracy. One study found that people who were never sick with COVID-19 had a positive TCR assay result after being vaccinated.

If you're looking for a test that can tell you if you were infected with the virus, regardless of vaccination status, a nucleocapsid test might be a better option. This test looks for antibodies your body created against a SARS-CoV-2 protein called a nucleocapsid protein. This protein isn’t included in the available COVID-19 vaccines. So you can only make antibodies against it if you’ve been infected with the virus.

It’s important to note that TCR assays and nucleocapsid tests aren't meant to diagnose a current COVID-19 infection. They can only provide information about past infections. So if you believe you’re currently sick with COVID-19, it’s best to get tested with an antigen test or a PCR test. Check out our other GoodRx Health article on COVID-19 testing for more detailed information.

Does COVID-19 immunity protect against newer strains of the virus?

The concern with COVID-19 variants is whether the vaccines and medications available to treat or prevent it are still effective. 

As discussed earlier, a booster dose of the mRNA vaccines remains is initially about 91% effective at preventing COVID-19 hospital stays. Similarly, a booster dose of the Johnson & Johnson shot is thought to be about 85% effective at preventing hospitalizations — even with the more recent Omicron subvariants. The research data for both types of vaccines were collected while the Omicron variant was the predominant strain.

Another large concern when it comes to COVID-19 variants has been that certain monoclonal antibody treatments for people who are presently sick might not work. In fact, the FDA revised the authorizations for two different monoclonal antibody treatments in January 2022. These two treatment regimens aren’t currently available in the U.S. because they aren’t effective against Omicron subvariants. 

Thankfully, research suggests that the monoclonal antibody sotrovimab and bebtelovimab is still effective against BA.4 and BA.5. Other treatments that aren’t monoclonal antibodies may also be effective against newer Omicron subvariants. This includes medications like remdesivir (Veklury), Paxlovid (nirmatrelvir/ritonavir), and molnupiravir. 

Specific vaccine and treatment effectiveness information changes frequently. Be sure to check out our COVID-19 vaccine effectiveness and COVID treatments articles for the most up-to-date information.

Will I need to get the COVID-19 vaccine every year? 

Currently, a single booster dose is recommended for all COVID-19 vaccines in younger adults and children older than 5 years old. A second booster is recommended if you are 50 and older, or you are 12 years and older and immunocompromised. Boosters for Pfizer’s Comirnaty can be given to people ages 12 and older. Boosters for Moderna’s and Johnson & Johnson’s vaccines can be given to adults ages 18 and older. However, the CDC prefers the Pfizer or Moderna vaccines over the J&J vaccine when possible. 

But with the newer variants, will further boosters be needed? 

On June 30, 2022, the FDA advised vaccine manufacturers to develop modified ‘bivalent’ COVID vaccine boosters that add an omicron BA.4/5 spike protein to the original recipe. They had previously been developing a new booster based on omicron BA.1 — so it’s back to the drawing board now. It’s not clear yet when this bivalent COVID booster will be available. By the time it is, the COVID virus will have evolved again, and a new variant or subvariant will probably be with us — or on its way. 

Currently, experts from the FDA and CDC are saying no. Plus, reports from Israel have shown that a fourth dose of Pfizer’s vaccine hasn't provided enough protection against Omicron.

So for right now, annual COVID-19 vaccines aren’t needed. This question will continue to be investigated, and new recommendations will be made as needed.

Why trust our experts?

Written by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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