COVID-19 vaccines help people build up protection to the virus without having to get sick and risk illness or death. We still need more time and evidence to know how long immunity will last following a COVID-19 vaccination.

Similarly, if you are exposed to the COVID-19 virus (not the vaccine) and build up natural immunity, the next time you're exposed your antibodies will likely disarm the virus so you don't get infected or have symptoms. In less common cases, you would at least be protected from a more severe case of COVID-19.

We don’t yet know exactly how protective “natural” antibodies are, and for how long. The British Society of Immunology states that the immunity acquired from a COVID-19 infection is variable, and its duration is unknown, adding that it might be lower in people who had a mild COVID-19 infection. We do know that there have been very few cases of COVID-19 reinfection, and that immunity acquired from one variant of COVID-19 is not guaranteed to protect against a different variant.

A key scientific difference between these two scenarios—immunity through vaccines vs. immunity from getting infected — are the parts of the virus that are helping to build that immunity. When designing a vaccine, researchers carefully expose individuals to a part or parts of the virus that help us produce immunity-boosting antibodies. Natural COVID-19 infection exposes people to the whole virus—not a carefully selected set of its traits.

Importantly, it’s not feasible to compare immunity from vaccination to immunity from infection accurately. Different vaccines have different ingredients and mechanisms, and trigger different immune responses in different people. In some cases, a vaccine might not provide as strong of an antibody response as the virus itself. Other times, it may be the vaccines that trigger the stronger antibodies. Antibodies aren't the only measure for immunity against viruses, either.

Current evidence now suggests that both vaccinated and unvaccinated individuals can be carriers of COVID-19, posing a threat to their communities. A study conducted in Kentucky, United States, between May and June of 2021 examined people who had previous COVID-19 infection in 2020, and compared the number of repeated infections among those who were later vaccinated, and those who were not. The study found that the group who was not vaccinated after having had a previous infection had more than double the likelihood of getting reinfected by COVID-19. Because of this study, CDC Director Rochelle Walensky urges every eligible person to get vaccinated even if they had previously gotten a COVID-19 infection.  Combined with the threat of reinfection and breakthrough infections by the Delta variant, the United States’ Center for Disease Control and Prevention has re-issued the mask mandate for public indoor spaces, regardless of vaccine status. It is advisable to maintain social-distancing, avoid crowded areas, hand washing and to continue using masks indoors in order to help end this pandemic and protect yourself, and your close contacts. 

Antibodies are crucial for fighting certain types of infections, including COVID-19. Through a range of mechanisms, and in coordination with different parts of the immune system, some antibodies can completely disarm a virus.

Information has circulated online that getting infected with COVID-19 produces a better antibody response than the vaccine. Whether an antibody response following a vaccine is stronger than one following infection depends on a range of factors, and can go both ways. 

Additionally, though vaccines can protect individuals from getting COVID-19, comparing the two types of immunity can be difficult because the purpose of vaccine development for COVID-19 is to prevent severe illness and death, not the infection itself.

New evidence from researchers in Israel suggests that getting vaccinated after a COVID-19 infection provides more protection than the vaccine, or the infection, by themselves. The study also concluded that people who vaccinated without prior COVID-19 infection were more likely to get infected than those who had natural immunity from a previous infection. However, the study did not capture asymptomatic cases, as these recover on their own without testing and are not detectable through medical records. More research is currently needed to confirm this finding.