COVID-19 immunity: What we know so far about the vaccine, 'natural' immune response

Even if you've recovered from a coronavirus infection, the CDC says you should still get a COVID-19 vaccine.

Dale Smith Former Associate Writer
Dale Smith is a former Associate Writer on the How-To team at CNET.
Dale Smith
4 min read

COVID-19 itself triggers some degree of immunity in those who've had it, but vaccines have proven to be a safer way of achieving protection against the disease.

James Martin/CNET

Coronavirus has now infected at least 100 million people worldwide, resulting in over 2 million deaths. Those who recover, however, do go on to develop some degree of immunity, protecting them against COVID-19, according to doctors who study COVID-19. Vaccines, including those that protect against coronavirus, also stimulate immunity and protect against disease, but in a different, safer way than the disease itself. And as the nationwide coronavirus vaccine rollout continues to pick up steam, questions surrounding COVID-19 immunity have naturally begun to surface. How protected are you against variants? How long does it last? Should those who've recovered from coronavirus still get the vaccine?

Much remains unknown about COVID-19, including whether immunity from the disease itself is stronger or weaker than that resulting from either of the two vaccines currently being dispensed. What is, however, known is that reinfection with COVID-19, while rare, isn't unheard of. Experts recommend everyone get the coronavirus vaccine whether they've had COVID-19 or not.

Watch this: When will I get my COVID-19 vaccine?

The Centers for Disease Control and Prevention says people who've had COVID-19 can, if they so choose, skip the vaccine for now while supplies are limited if they'd like to let others get ahead in line. Eventually, however, the CDC says they should get the vaccine just like everyone else. (There are factors that lead experts to suggest some people might not be good candidates for receiving the vaccine, but for reasons other than immunity.)

Here, we'll take a look at what we know about coronavirus immunity as it relates to both the disease itself and the vaccines available to protect against it. Keep in mind, mutations of the virus could potentially affect some or all of the information presented below. Plus, there isn't enough conclusive evidence at this point to know how every coronavirus vaccine relates to the new variants currently emerging. This story isn't intended to serve as medical advice. If you're looking for a site to administer a COVID-19 vaccine, here's what to know.


A coronavirus vaccine card can remind you when to come back for your second dose.

US Department of Defense

What is immunity from the coronavirus exactly and how do you get it?

The immune system is your body's defense against germs that can make you sick, including bacteria, fungi, toxins and viruses. It's made up of several different organs that produce cells and proteins designed to protect against disease. Over the course of your life, the immune system detects, remembers and defends against invading germs -- this resistance is "immunity." Doctors are particularly interested in antibodies and T cells when it comes to COVID-19, as both have been shown to help protect against infection.

Immunity that you build up is called acquired immunity and there are essentially three ways to get it: being naturally exposed to infection or disease, receiving someone else's antibodies as a form of treatment or receiving a vaccine.


Because there's still a limited supply of COVID-19 vaccine, the CDC says those who've recovered from the disease can wait to get it, but not forever.

Sarah Tew/CNET

Vaccine vs. 'natural' immunity: Which lasts longer?

Immunity to some diseases can last a lifetime, like measles and mumps. Other diseases trigger long-lasting but not ironclad immunity, like chickenpox, which can reappear as shingles later in life. And with still other diseases like the flu, immunity is narrow and short-lived, in part because the viruses that cause influenza mutate so rapidly.

A January 2021 study detected a level of coronavirus antibodies consistent with immunity as long as eight months after patients were infected. A similar but separate study from November concluded that protection lasts at least five to seven months post-infection. 

Vaccines against COVID-19 haven't been around long enough to provide any definite answers, but most experts seem to expect at least a year's worth of immunity after being inoculated. That could mean yearly "booster" shots will be necessary to stamp the virus out completely. The CEO of one of the companies behind a COVID-19 vaccine -- Moderna's Stephane Bancel -- has said the world will have to live with coronavirus "forever."


Until the population has reached a certain level of immunity, expect most people to continue to limit going out in public.

James Martin/CNET

Vaccine vs. 'natural' immunity: Which is stronger?

Just because you've developed some degree of immunity against a particular disease doesn't mean there's a 0% chance you'll contract it if exposed. That's what researchers are referring to when they say, for example, that the Moderna vaccine is 94.5% effective. That means, for every 1,000 people given the vaccine, 945 won't contract the disease if exposed -- but 55 still could. The other vaccine currently authorized in the US, Pfizer's, is 95% effective, meaning 95 out of every 100 people who get it will be protected.

There's a dangerous rumor going around that COVID-19 -- the disease itself -- is 99% effective at preventing reinfection. While it's unclear how accurate that number actually is, one fact remains -- COVID-19 has killed more than 2% of those who've been infected by it. Vaccines, on the other hand, not only prevent infection -- they save lives

Vaccine vs. 'natural' immunity: Which is safer?

In addition to the risk of death, doctors have identified a whole litany of long-term effects patients recovering from COVID-19 have endured. These so-called "long-haulers" have experienced coughing, sometimes severe fatigue, body aches, joint pain, shortness of breath and an assortment of neurological disorders. For some, symptoms persist weeks and even months after the initial infection mostly subsides. 


Some COVID-19 symptoms can persist for weeks and even months in a small percentage of people who get the disease.

Sarah Tew/CNET

So far, there have been zero deaths linked directly to any of the coronavirus vaccines currently being distributed worldwide. Also, despite a small number of recipients experiencing some type of allergic reaction, usually minor, overall negative responses of any sort are quite minimal. The most common side effects are pain or swelling around the injection site and fever, chills, tiredness or headache.

Now that vaccines have arrived, some kind of return to normal may be on the horizon, but until then everyone will need to continue to wear masks and socially distance. Also, to hasten a return to the office, your employer could legally require you to get the vaccine. Whatever you do, however, be careful to look out for any of the multiple vaccine-related scams going around.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.