Breakthrough COVID-19 Cases

Even after getting the COVID-19 vaccine, some people can contract the virus. Dr. Maryrose Laguio-Vila explains the science behind it all – and why it isn’t as troubling as it may seem.

Aug. 11, 2021 4   min read

One of the main benefits of being fully vaccinated is dramatically reducing your chances contracting the COVID-19 virus. Despite lowering that chance, there is still a possibility of testing positive.

Maryrose Laguio-Vila, MD, is an Infectious Disease specialist with Rochester Regional Health. Her knowledge of the virus and the vaccine are helpful in understanding how getting vaccinated is still the best way to protect your health.

How the vaccine protects the body

The three COVID-19 vaccines being used in the United States are manufactured by Pfizer-BioNTech, Moderna, and Johnson & Johnson.

The Pfizer and Moderna vaccines use mRNA (messenger RNA), which is essentially a code for the cells in your body. This code teaches the cells to make the protein that is part of the coronavirus structure. When that protein is then seen by the person’s immune system, it learns how to recognize that protein and fight coronavirus should the body see that protein again.

The Johnson & Johnson vaccine uses a disabled adenovirus – a type of virus similar to the common cold – to teach your immune system how to fight COVID-19. Since the adenovirus virus is disabled, it is completely separate from coronavirus and cannot replicate once it is inside your body.

Once injected, the adenovirus cells give instructions to the body’s immune system on how to recognize and fight the coronavirus if the body ever becomes infected.

So far, data from the FDA, CDC, and drug companies indicate a strong level of protection against COVID-19 for at least six months after a person has been inoculated.

“We now have information on hundreds of millions of people across the world,” Dr. Laguio-Vila said. “We see the incidences of hospitalizations related to COVID and deaths related to COVID be significantly less with people who are vaccinated.”

Breakthrough COVID-19 cases

A breakthrough COVID-19 case is determined by the detection of the SARS-CoV-2 virus in someone who has completed their single or double dose of COVID-19 vaccination and waited two weeks after their last vaccine.

It is important to note that a case is counted by a positive test – not a person experiencing symptoms of the virus. Dr. Laguio-Vila states less than half of the fully-vaccinated people who test positive for COVID-19 actually show symptoms.

“When we look at the number of cases of breakthrough infections that are reported, it is very illustrative if we see that data further broken down by people who had had respiratory symptoms or which ones did not have any symptoms at all,” Dr. Laguio-Vila said. “By seeing this, we can get a better sense of if the breakthrough infections actually made people sick, or was it just an asymptomatic infection with no consequences. And what we see now is that few people with breakthrough infections were actually only positive for the test, but not actually sick.”

Is it common to get COVID-19 after being vaccinated?

Statistically speaking, it is highly unlikely to get the COVID-19 virus after getting vaccinated. As mentioned previously by Dr. Laguio-Vila, it is even less likely to exhibit symptoms of the virus as a fully-vaccinated person.

As of August 2, 2021, more than 164 million people in the U.S. have received the COVID-19 vaccine. Of those people, 7,525 people had a breakthrough COVID-19 infection that led to a hospitalization or death.

“The majority of those patients are asymptomatic and are hospitalized for reasons other than COVID-19,” Dr. Laguio-Vila said.

Based on CDC data reported to the Vaccine Adverse Event Reporting System (VAERS) between January and April 2021, roughly 0.01 percent of patients experienced breakthrough COVID-19 infections.

How much is the Delta variant to blame for this?

The short answer: It’s complicated and we don’t fully know.

Studies on how effective the COVID-19 vaccines are on variants such as the U.K. or Delta are currently underway, so it is tough to determine with scientific accuracy exactly how effective the vaccines are at preventing breakthrough infections.

Read more: What to know about the Delta variant this summer

Dr. Laguio-Vila said it is important to make sure people are getting tested if they are significantly exposed to a positive COVID-19 case so they can add to the data of who is contracting COVID-19 – both for unvaccinated and vaccinated people.

If you can still get and spread COVID-19, why bother getting vaccinated?

Based on the studies and real-life examples of people who are vaccinated, a person who is vaccinated has much more protection than a person who is unvaccinated.

Even if you are one of the extremely rare breakthrough cases, you will have far more protections against severe symptoms of COVID-19, hospitalization and death.

“It’s like a bulletproof vest. You might get struck, but you don’t get shot in the heart,” Dr. Laguio-Vila said. “Your vaccine helps you not get severely ill. You may have milder symptoms, if any, but it will help you from not getting so severely ill and certainly prevents bad outcomes and death.”

How much will masking help?

On July 27, 2021, the CDC issued updated guidance on wearing masks indoors. All people living in areas of “substantial or high transmission” are recommended to wear a mask, regardless of their vaccination status.

Since this virus is not something we have dealt with before, Dr. Laguio-Vila said there is no single tactic that will stop the virus in its tracks and completely shut it down.

“If only the vaccine was the only thing we needed to do,” Dr. Laguio-Vila said. “The necessity of maintaining hygienic practices and masking together may be the synergistic approach we need to take to stop all of these waves from happening. It probably cannot be either one or the other.”

In addition to wearing a mask, you can also:

  • Stay six feet apart while indoors
  • Wash your hands for at least 20 seconds
  • Get vaccinated

Even though it can be a difficult decision to wear masks indoors again, placing the priority of everyone’s health above a person’s individual desires is something that is helpful to embrace.

“Having empathy is important,” Dr. Laguio-Vila said. “Not everyone may have the fortune of having a good immune system or a home separate from a busy apartment building or healthy kids or healthy parents or the ability to work from home. Vaccination protects not only yourself, but those around you who cannot get the vaccine, like children currently, or those with weak immune systems that won’t respond to a vaccine.”

Protecting children under 12

There is not a significant amount of data about the likelihood of fully-vaccinated people spreading COVID-19 to children who are unvaccinated due to their age.

Currently, only children ages 12 and older have been approved to receive the Pfizer-BioNTech vaccine.

In the absence of more data, the best things families can do is to keep their children washing their hands thoroughly and wearing a mask while in public indoor spaces.

“The best way to protect your family is to remain cognizant and vigilant about hand hygiene and masking when you’re out so that way when you come home, you don’t bring something with you,” Dr. Laguio-Vila said.

Rochester Regional Health researchers are involved with studies of the COVID-19 vaccine for children. Those studies are reportedly showing “promising results”, specifically with their ability to create an immune response in the patients being studied. No timeline is available for the authorization of that vaccine.

NEXT STEPS Talk With A Doctor About The Vaccine

Researchers at Rochester Regional Health continue to devote their careers to learning and understanding how infectious diseases such as COVID-19 work - and how to effectively treat them. Sharing a safe vaccine is one of the many facets of their work.

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Maryrose R. Laguio-Vila, MD
Internal Medicine, Infectious Disease
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