Talk to Patients About: Breakthrough Infections for COVID-19 Vaccinations
By Sean Price

This material is designed to help you talk to your patients and help them understand the benefits of vaccines. Find printable infographics and helpful videos for your patients at TMA’s Talk to Your Patients webpage. Also, check out Vaccines Defend What Matters, the Texas Medical Association’s integrated, multimedia public health education and advocacy effort, to find more resources. 

The new mRNA vaccines for COVID-19 are highly effective at giving people immunity against the disease. But as with all other vaccines, that immunity is not 100% for everyone who receives them. 

“Vaccines prevent you from getting the full form of the disease most of the time, but they don’t prevent infections entirely,” said Donald Murphey, MD, pediatric infectious disease specialist at Dell Children’s Medical Center in Austin and a member of the Texas Medical Association’s COVID-19 Task Force

“They boost the immune system to where your immune system knows what that germ looks like and is ready to respond to it,” he said. “But that doesn’t mean that germ can’t cause a very mild infection [in a vaccinated person].” 

Patients should remember two important things about these “breakthrough” infections – so named because the illness breaks through the defense created by the vaccine, Dr. Murphey says. 

First, vaccinated people who get a breakthrough infection have a lower risk of developing severe symptoms than unvaccinated people. 

Second, severe breakthrough infections are rare, statistically speaking. Studies about hospitalization or death tied to breakthrough infections for COVID-19 vaccines remain incomplete and are complicated by the emergence of the delta variant, according to the Centers for Disease Control and Prevention. But “vaccine breakthrough infections occur in only a small fraction of all vaccinated persons and account for a small percentage of COVID-19 cases,” CDC stated in a May 2021 report.

The way to prevent breakthrough infections is simple: More people need to be vaccinated against COVID-19, Dr. Murphey says. That is the only way to reach herd or “community” immunity – the point at which so many people are vaccinated that a disease finds it difficult or impossible to spread. 

Because the delta variant – now the dominant strain of COVID-19 in the U.S. – spreads so fast, at least 80% of the population would need to be vaccinated, according to the Infectious Disease Society of America. At this writing, about 52% of Americans and 56% of Texans were fully vaccinated. 

“We know how we get through epidemics, and that’s to get everybody immunized,” he said.          

Below is a Q&A you can share with patients covering information on breakthrough infections.

What is a breakthrough infection?

A vaccine puts your immune system on alert about a specific disease. The next time you encounter that disease, your immune system is ready with a defense. But for a small minority of people, that defense is slightly weaker than in others. Those people can still get sick with what’s called a “breakthrough infection” because it breaks through the vaccine’s protection. 

Why get vaccinated if I can still get sick?

Most people who become vaccinated don’t become sick. Though a minority of vaccinated people can get breakthrough infections, those infections usually result in mild symptoms that don’t require hospitalization. Unvaccinated people run a much greater risk of having severe symptoms that can leave them permanently disabled or dead. 

How can breakthrough infections be stopped?

Masking and social distancing help keep the disease from spreading. But as many people as possible need to become vaccinated. Vaccines prevent the spread of disease in two ways. When more people in the community get the vaccine, it is harder for the virus to spread to new people who are not immune. The number of new infections decreases. This protects everyone in the community. It even protects people who do not respond well to the vaccine, such as those with weak immune systems. They are being protected by “herd” or “community” immunity. That means so many people become vaccinated that the disease finds it difficult or impossible to spread. 

What happens if we don’t reach herd immunity?

Diseases like COVID-19 mutate quickly to forms that spread faster and kill more people. That has already happened. The delta variant of COVID-19 spreads much more quickly and may be more deadly than the original virus. Without herd immunity, the delta variant and other variants will continue to mutate. As they do, they could change to a form that cannot be addressed by our current vaccines. If that happens, it might take several more months or years to bring COVID-19 under control. 

Correction: This story previously contained an incorrect percentage of Texans that were fully vaccinated at this writing. It has been updated.

Last Updated On

September 06, 2023

Originally Published On

August 30, 2021

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Sean Price


(512) 370-1392

Sean Price is a reporter for Texas Medicine and Texas Medicine Today. He grew up in Fort Worth and graduated from the University of Texas at Austin. He's worked as an award-winning writer and editor for a variety of national magazine, book, and website publishers in New York and Washington. He's also helped produce Texas-based marketing campaigns designed to promote public health. Sean lives in Austin and enjoys hiking, photography, and spending time with his wife and two sons.

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