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Vaccination is Best: Immunity benefits of COVID-19 vaccination vs. COVID-19 infection

A positive test does not equal protection – getting vaccinated after COVID-19 will boost your immune response and protect you against new variants of the virus.

By Stacey Wiedower

“I have the antibodies because I had COVID, so I don’t need the vaccine.” This statement is one of the most common reasons unvaccinated people use to explain why they won’t get the COVID-19 vaccine. The problem is science doesn’t back it up.

“After infection, not everyone has antibodies,” said Diego Hijano, MD, Infectious Diseases. “When you compare antibody levels of those who had an actual infection, they are similar to those uninfected after one dose of the vaccine. And we know that one dose of the vaccine is not sufficient to protect you.”

One dose is especially insufficient against variants of concern, including the highly contagious delta variant that is driving the current surge of COVID-19 infections. Fully vaccinated people have more antibodies than previously infected unvaccinated people. In addition, antibodies from infection provide less protection against variants of concern than antibodies induced by the vaccine.

If you do get an antibody test, can you learn anything from it?

There are several antibody tests available. Some tests will tell you whether you have had COVID-19 in the past. Other tests will let you know if you have antibodies after being vaccinated. Some tests are qualitative, and they will determine if you have antibodies or not. Others can give you a number that reflect your levels. You might think that high enough levels of antibodies mean you don’t need to get vaccinated. However, protection against the virus still can’t be nailed down to antibody levels in a simple blood test. Furthermore, lack of standardization among the commercially available tests for antibodies makes it even harder to decipher the results.

On an individual level, antibody tests can be useful for picking up evidence of a past COVID-19 infection. They’re also helpful to researchers studying the prevalence of the virus across a population or tracking the degree to which antibody levels decrease over time.

In a recent Town Hall presentation, St. Jude President and CEO James R. Downing, MD, addressed the question of whether someone who has had COVID-19 is protected against reinfection. His answer was clear: “No. Immune response against the infection is less than the immune response generated due to the vaccine.”

It is safe to receive the COVID-19 vaccine even if you have previously tested positive, and we recommend all those who are eligible receive it. 

What about the benefits?

Graphic showing COVID-19 rates for Shelby County, TN

A recent study showed that vaccination boosts the memory antibodies that develop after infection, producing an “outstanding response.” Compared with unvaccinated participants, those who had received at least one dose had higher quantity and quality of antibodies. In addition, the antibody levels against the variants surpassed the levels from those infected or fully vaccinated individuals.

Two teams, in North America and the UK, recently published studies in Science demonstrating that a single dose of an mRNA vaccine substantially enhances the immune response to SARS-CoV-2 variants among patients with a prior infection—a phenomenon some are calling “hybrid immunity.”

What’s more, a recent study in Kentucky showed that people who had COVID-19 and did not later get the vaccine are more than twice as likely to be reinfected as those who had the disease and did get the vaccine.

Graphic illustrates Hybrid Vigor Immunity

What about side effects?

For some vaccine-hesitant people, an argument against vaccination springs from a worry that the side effects of vaccination might be worse than the effects of the virus. Again, the science supports that vaccination poses less risk.

Most side effects people have from the COVID-19 vaccines are mild and spring not from active infection, but from the vaccine’s activation of the immune system. Common symptoms include pain or swelling at the injection site, headache, body aches, chills, fever, nausea or fatigue. Symptoms generally subside in a few days. Some people experience no symptoms. A small number of people have experienced side effects that are extremely rare. Learn more.

Risks that spring from COVID-19 infection are also well-documented and far more common. Almost 30 percent of adults ages 18-39 suffer from prolonged symptoms following COVID-19 infection, ranging from impaired memory, reduced sense of smell, taste or vision, nerve pain, dizziness, headaches, seizures, fatigue and more.

When a cohort of low-risk health care workers with mild COVID-19 was assessed eight months after infection, one in 10 still had at least one symptom that was disrupting their work, social or home life. The most common long-term symptoms are loss of smell and taste, fatigue and respiratory problems.

Individuals who had COVID-19 and are experiencing some of these prolonged symptoms may benefit from vaccination. Preliminary data shows that many of these symptoms improve and/or disappear after getting vaccinated. Finally, Multisystem Inflammatory Syndrome following COVID-19 infection remains a rare, yet life-threatening complication in both children and adults.

The vaccine is safe and effective even after infection with COVID-19. "There are no increases in complications from the vaccine if you get it after having COVID-19,” Downing said. “So, get the vaccine.”

What about breakthrough cases? Why should I get vaccinated if I can get COVID-19 anyway?

It's true that some people who are fully vaccinated against COVID-19 will contract the virus. These “breakthrough” cases are expected yet uncommon, though they are occurring in areas with high virus transmission. It’s important to note that breakthrough cases rarely result in serious illness.

“Those breakthrough cases by and large are not very severe,” Downing said. “The vaccine is protecting (people) from getting severe symptomatic disease, from ending up in the hospital, or from dying from it. There are rare examples, but the frequency is infinitely less than it is in the unvaccinated.”

If you question the vaccine’s effectiveness or believe your previous COVID-19 infection might be enough to prevent reinfection, an example from a recent day at Houston Medical Center and Perry Hospital provides a clear picture.

On this day, 74 out of 83 patients hospitalized with COVID-19 were unvaccinated. All 24 COVID-19 patients in the ICU were unvaccinated. And all 10 of the sickest COVID-19 patients – those on ventilators – were unvaccinated. Similar statistics are playing out in Memphis-area hospitals right now. Across the country, former vaccine skeptics are urging loved ones from their hospital beds to get the vaccine.

The bottom line? Vaccination is and will remain the best line of defense against COVID-19. Vaccines are also the fastest and best way we can protect our St. Jude patients.

“We know and we have evidence that some vaccines actually induce better immune response than that induced by infection, and we continue to see that COVID-19 vaccines align with that,” Hijano said. “So, the recommendation continues to be for everyone to be vaccinated even if you had COVID-19.”


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