COVID-19 Antibody Protection: What Is It and Why Does It Matter?

Key Takeaways
  • The body’s immune system is naturally programmed to produce antibodies that protect the body from infection, illness, and disease.

  • Natural immunity can be very effective, but research shows that vaccine-induced immunity can go much further in terms of providing protection, especially in regards to COVID-19.

  • Preliminary studies also indicate that natural immunity to COVID wanes faster over time than immunity provided by COVID vaccination.

  • Antibody tests are not effective diagnostic tools for infection. They can confirm if someone has previously been infected with COVID or that they have been vaccinated against the virus, but it will not differentiate between the two.

The immune system works to protect the body from outside invaders – such as bacteria, viruses, and fungi, and toxins.[1] We are all born with an innate immune system and over the course of our lifetime we develop an adaptive immune system after being exposed to various outside invaders. When the body becomes infected with a virus or bacteria, for example, the immune system responds by producing antibodies to fight it off. The key benefit of having antibodies for a particular disease is that they provide immediate added protection. So, even if you do get sick, your body will be more effective in preventing severe illness[2]. Vaccines have a similar effect in that they imitate infection to familiarize your body with how to fight it off.

When it comes to COVID variants, including Omicron, there are many questions surrounding the effectiveness of infection-induced immunity versus vaccine-induced immunity. Here we break down the essentials of antibodies against the SARS-CoV-2 virus, which causes COVID – what they are, how they work, and which method of protection is the most effective in the long run.

What are COVID antibodies and how do they work?

Antibodies are Y-shaped specialized proteins that your immune system produces to protect against viruses, bacteria, and other foreign substances that can be damaging to health and cause serious illness.[3]

There are two main ways for our immune system to make antibodies against various pathogens, including the virus that causes COVID: through previous infection and vaccination. After infection or vaccination, the immune system learns how to identify and destroy a particular germ or virus if it ever enters the body again. Studies indicate that COVID antibodies circulate around the body for approximately 10 months after infection.[4]

Is natural immunity to COVID as effective as vaccine-induced immunity?

There is overwhelming evidence that vaccine-induced immunity against COVID-19 is superior to that provided by natural infection. In fact, unvaccinated individuals are five times more likely to become reinfected with SARS-CoV-2 compared to those who are fully vaccinated and haven’t had a prior infection.[5] Note that the degree of natural immunity will vary depending on the person and severity of infection.

For example, someone who experiences a mild or asymptomatic case of COVID may not have a particularly strong natural immunity to the virus.

New studies also show that natural immunity to COVID wanes faster over time than immunity provided by COVID vaccination. And a new preprint paper (not yet peer-reviewed) suggests that immunity from a prior infection of COVID is only 56% effective against symptomatic infection of Omicron. There is also substantial evidence to suggest that getting vaccinated after infection significantly enhances protection and further reduces the risk of reinfection.

How long do antibodies last?

COVID antibodies last for at least several months, though evidence shows that protection lasts longer after vaccination or vaccination plus infection rather than from infection alone. One study published in August 2021 shows that having a prior COVID infection but not getting vaccinated doubles your risk of getting re-infected with the virus compared with those who are fully vaccinated.

How do scientists study antibodies and how does this information inform the pandemic response?

Scientists study antibodies by measuring antibody levels collected from blood samples of people infected with COVID and vaccinated against COVID. The WHO International Standard (IS) for antibodies helps to facilitate the standardization of SARS-CoV-2 serological methods to enable comparison and harmonization of datasets across laboratories. This research is vital to improving our collective scientific understanding of the virus and helping public health officials determine the efficacy of vaccines and therapeutics.

Does an antibody test diagnose an active COVID infection?

Antibody tests are not used to diagnose an active COVID infection. Most healthy adults need one to two weeks for their immune system to produce COVID antibodies, which is why an antibody test is not an effective diagnostic tool for infection. Instead, antibody tests can be used to confirm that an individual has previously been infected with COVID or that they have been vaccinated against the virus – but it will not actually differentiate between the two strategies. Another common question is whether or not the amount of antibodies a person has can predict the strength of protection against getting COVID-19. The answer is: it cannot.

Though having COVID antibodies can help your body protect itself against infection and illness, it shouldn’t be interpreted as carte-blanche to forgo all preventative measures, like social distancing or wearing your mask in crowded, indoor, public spaces. The best way to protect yourself and your community against the spread and impacts of COVID is a multilayered approach, including getting vaccinated and boosted when eligible and testing after exposure or when symptomatic.

Resources:

  1. The Immune System. (n.d.). Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/the-immune-system
  2. COVID-19 and Your Health. (2020, February 11). Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/your-health/about-covid-19/antibodies.html
  3. Rush, L., & Hebert, C. (2021, November 10). What do antibodies do to protect against COVID-19? The Ohio State University Wexner Medical Center. https://wexnermedical.osu.edu/blog/how-antibodies-protect-against-covid-19
  4. King’s College London. (2021, October 29). COVID-19 antibodies remain in the body 10 months after infection. https://www.kcl.ac.uk/news/covid-19-antibodies-remain-in-the-body-10-months-after-infection
  5. Bozio, C. H. (2021, November 4). Laboratory-Confirmed COVID-19 Among Adults Hospitalized . . . Centers for Disease Control and Prevention. https://www.cdc.gov/mmwr/volumes/70/wr/mm7044e1.htm

DISCLAIMER: This article is for general information purposes only, does not constitute medical advice and is not intended to be relied upon for medical diagnosis or treatment. If you are experiencing a medical emergency, dial 911 immediately.