Being fully vaccinated (which means receiving a full vaccine dose and booster shots as recommended) remains the best way to protect yourself against COVID-19 — people who are vaccinated are less likely to get sick, and they are far less likely to develop serious symptoms, require hospitalization, or die from COVID-19 if they do become infected.
And research has proved that having contracted and then recovered from COVID-19 adds additional protection. But that protection is not 100 percent effective, and its strength does seem to wane over time.
After recovering from COVID-19, you may wonder about the chances of reinfection. In this post, we will answer some frequently asked questions.
Can you get COVID twice (or more)? The simple answer is yes. Even people who have both been vaccinated and recovered from a case of COVID-19 are at risk. The good news for vaccinated people is that they are much less likely to develop severe symptoms. And even if you have already been infected, the vaccine can provide greater coverage from new variants and lessen or even eliminate symptoms if you are reinfected.
After you recover from a viral infection, your immune system retains a “memory” of the virus and therefore can more easily recognize and fight it if it’s encountered again. This both protects against disease and reduces disease severity.
After recovering from COVID-19, or after receiving the vaccine, your body forms antibodies. Antibodies are specific proteins made by the body for protection against future infection. Some antibodies start to disappear over time, increasing the risk of reinfection. The longer it has been since your last infection or vaccine dose, the greater your chance of getting COVID-19 again is. This happens over the course of months, typically. According to the CDC, it is unlikely that a person will be infected with COVID-19 twice in six months, but it is possible. The duration of protection against reinfection can vary from person to person, and it is unclear what an “average” length of time is. The initial severity of the infection can have an impact on the severity of the second infection and how the body responds in regards to the production of antibodies and T-cells.
COVID-19 reinfections happen for several reasons:
• Time: The COVID-19 pandemic has entered its third year, and many original infections occurred many months ago or even a couple of years ago. As time passes, the acquired immunity that recovering from COVID-19 provides decreases.
• Vaccine immunity deteriorating over time: The effectiveness of the antibodies in the COVID-19 vaccine can start to wane as time passes. This is why it is important for anyone who is eligible to get the third or fourth dose of the vaccine (or booster shot). This helps to maintain vaccine immunity.
• The relaxation of safety precautions. At the beginning of the pandemic, more people were vigilant about wearing masks, frequently washing their hands, and social distancing. These are all highly effective ways to stop the spread of COVID-19. As we enter the third year of the pandemic, guidelines have been relaxed, as have personal habits.
• Mutations leading to new, more contagious variants. The Omicron variant recently caused a surge in COVID-19 case numbers, because it is more contagious than previous strains of COVID-19. In addition, previously developed antibodies may not be as effective against new variants. Having had the vaccine will help to minimize the risk of severe infection and death from new variants.
Scientists are continuously learning new information about COVID-19, including how reinfections tend to present in patients. Symptoms to watch for include:
• Fever and/or chills
• Sore throat
• Muscle or body aches
• Vomiting or nausea
• Loss of taste
• Loss of smell
• Difficulty breathing and shortness of breath
As COVID-19 mutates over time, new variants have emerged, such as Delta and Omicron. Both of these variants are highly contagious. Delta is twice as contagious as the original strain, Alpha, and Omicron has taken over as the prominent variant in the United States. Experts believe that because these mutated variants are more likely to evade past defenses, such as antibodies and T-cells, they are more likely to cause reinfection. When compared to Delta, Omicron is as much as five times more likely to cause reinfection.
When we get sick, our bodies create antibodies and T-cells to fight infection. The antibodies can then stay in our body and potentially fight off the same infection at a later time. They are the reason that we don't, typically, get sick with the same viral illness twice in close succession. Antibodies have the capacity to destroy infectious cells or simply prevent them from entering the body’s cells. Some antibodies are present for a lifetime, while others start to diminish over time — as is the case with COVID-19. In regards to antibodies and COVID-19 reinfection rates, antibodies are highly effective. But they eventually start to wane, and that makes us more susceptible to reinfection.
This is a tricky question, as testing within 90 days of a COVID-19 previous infection can possibly result in a false positive result. If you get a positive test result after 90 days, it is a good idea to check with a healthcare provider to confirm reinfection. Why wait 90 days? Well, even though you may no longer be contagious, some leftover COVID-19 genetic material can stick around in your nasal passageways. That genetic material can be picked up for up to three months by PCR (polymerase chain reaction) tests and result in false positives.
Health professionals recommend taking an antigen test after your five-day quarantine period, because antigen tests detect actively replicating viral DNA, so they are less likely to produce a false positive when compared with PCR tests. The chances are that if a test is positive, you are still infected. Most at-home tests are antigen tests, making them convenient and relatively affordable. (Find COVID-19 testing near you.)
Say you have had COVID-19. Your body has created antibodies. So what's the point of getting vaccinated?
Yes, it's true that you may have antibodies to help fight reinfection. Even so, it is still highly advised that everyone get vaccinated, whether they have had COVID-19 or not. Vaccines have longer-lasting antibodies along with the ability to train your T-cells. It has been shown that people who are unvaccinated have a 2.34 times greater chance of being reinfected with COVID-19. People who are immunocompromised have an even greater chance of reinfection. This makes it vitally important that they receive the vaccine and booster shots in order to stay stronger and have longer lasting immunity. Vaccines help to prevent reinfections and, more importantly, prevent severe infection and death.
What about getting COVID-19 after the vaccine? There is a chance of breakthrough cases after receiving the vaccine. The important thing about vaccines is that even if a breakthrough case occurs, it is typically much less severe than the illness in an unvaccinated person. Some people worry about the side effects of the vaccine, but the cost-benefit ratio shows that the benefits of the vaccine far outweigh any negative potential side effects. (Side effects you may find discussed online, such as blood clots, are extremely unlikely to occur.)
Studies and research are ongoing and more are being planned. Such research includes looking at long-lasting effects, reinfection, vaccine effectiveness, and more. In the grand scheme of things, information on reinfection is lacking. The confirmation of individual reinfection is difficult data to confirm. Some of the reasons for this are the lack of communication between labs, the lack of symptoms, and the need for the comparison of genetic material.
Many other studies and research are ongoing or being planned in order to learn more about how the virus affects us, the benefits of the vaccine for immunocompromised individuals, how to streamline testing, and more. One study by Johns Hopkins has shown the effectiveness of the vaccine on those that have had organ transplants.
If you have questions or concerns about COVID-19, download the Carbon Health app or visit carbonhealth.com to make a virtual or in-person appointment with a healthcare provider.
Carbon Health’s medical content is reviewed and approved by healthcare professionals before it is published. But note that our knowledge and understanding of COVID-19 are developing and changing very rapidly; if you have questions or concerns about COVID-19 precautions, treatments, and vaccinations, please talk to your healthcare provider.