Over 51 million people in the United States have been fully vaccinated against the COVID-19 virus, according to the Centers for Disease Control and Prevention, with more than 93 million Americans having received at least one dose of the vaccine.
As more people are being vaccinated, questions are changing from “how do I find a vaccine” to “how long will the vaccine protect me?”
Here is what researchers say about how long immunity will last after a COVID-19 vaccine.
First, what is immunity?
Immunity is the ability of the body to defend itself from “foreign bodies” such as viruses.
What can you do to get immunity?
There are two ways to gain immunity from a virus: Natural immunity, which occurs when your body makes antibodies after you become sick with a disease; and vaccine-induced immunity, when a vaccine prompts your body to make antibodies.
A vaccine is a medicine that helps your immune system build antibodies to fight viruses and bacteria that cause illnesses.
Your body naturally makes antibodies in response to a virus in your system.
How long does it take to build immunity to disease?
Usually, it takes a few weeks for your body to manufacture antibodies, or organisms that fight disease. It takes that amount of time whether you get a vaccine or have an illness.
You can get the disease if you come into contact with it within the time period after you have had a vaccine, but before enough antibodies are produced to fight the disease.
How long does immunity from a disease last after you have the disease or are vaccinated?
The length of time you are immune against a disease can vary. Some vaccines give your immunity for a lifetime after two or three doses, but other vaccines such as the influenza vaccine, require annual doses, called “boosters”, to continue the protection.
What about the COVID-19 vaccine? How long does protection last?
The challenge of discovering how long you are protected by the COVID-19 vaccine is that the vaccines in use in the U.S. have not been around for very long, so scientists only have a few months of research information to draw conclusions about how long their protection lasts.
The good news is that information appears to indicate protection for some time.
Researchers say they are seeing that those who have had COVID-19 and recovered appear to have long-term immunity that lasts for at least six to eight months, and could last years.
If you get sick with COVID-19, your immune system will make antibodies within a few weeks after you were infected, according to Christina Aungst, a community pharmacist writing for the GoodRX website.
Aungst pointed out that once you have developed natural immunity, your body will know how to fight the infection if you are exposed again, and it’s unlikely you will catch COVID-19 again.
Aungst also pointed to a recent study that found that natural immunity is still present in people eight months after they were infected.
Some researchers believe natural immunity to COVID-19 might last for several years, after another recent study showed that people who have recovered from COVID-19 have powerful and protective killer immune cells even when antibodies are not found in blood samples.
Three types of immune cells help to “remember” viruses that a person has contracted, and send a signal for the body to fight those viruses.
When it comes to vaccines, how long it takes to develop immunity can vary. The Pfizer-BioNTech vaccine is said to provide full immunity seven days after you receive the second shot. The Moderna vaccine offers full immunity 14 days after its second dose.
According to a study in the British Medical Journal, it’s believed that by some researchers that vaccines being used now will provide protection that could last for some time.
Another study cited by Aungst suggests that immunity could wear off quickly and require yearly shots to boost protection.
How do the variants affect immunity?
New strains of a virus are not uncommon, and so far, researchers believe that the current vaccines offer protection for at least two of the identified variants.
For the variant known as the South African variant, researchers found the vaccines less effective, but likely to offer some protection against it.
“I still think it is highly likely our vaccine will confer some protection, even against the South African variant, when it comes to more severe disease, particularly in older patients, which is ultimately the patient population we need to treat because they’re the ones that end up in hospital and do most poorly if they’re infected,” Mene Pangalos, executive vice-president of biopharmaceuticals research and development at AstraZeneca, told The Guardian.
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