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What You Need to Know About Breakthrough Cases of COVID-19

covid 19 vial

You may be hearing more about breakthrough infections among those vaccinated against COVID-19 and have questions. Do breakthrough infections mean I’m not protected? Am I at risk? Fortunately, Alex Benjamin, MD, Chief Infection Control and Prevention Officer with Lehigh Valley Health Network (LVHN), has answers to some of the most common questions about breakthrough COVID cases. 

Q. How common are breakthrough cases?

A. Locally we do not track every person who has a positive COVID test to see if he or she has been fully vaccinated. We do look at hospitalizations for COVID, and we know that 10%-15% of our hospitalized COVID patients have been vaccinated. While that sounds like a lot, there are many more in the hospital who have not been vaccinated. The bottom line is that vaccines are keeping people out of the hospital and saving lives. 

Q. Should people be concerned about breakthrough infections?

A. Certainly. The number of new positive cases has been steadily rising in our area since early July. Even if you are vaccinated, you are likely to encounter a COVID-positive person in your daily activities and it is possible to become infected. If you have tested positive for COVID, it’s important to stay home and isolate. If you have been exposed, you should be tested. 

N16838_1200x628_Pfizer Vaccines Get Full FDA Approval

COVID-19 Vaccine Receives Full FDA Approval

The FDA-approved Pfizer vaccine is available at all LVHN vaccine clinics.

Q. Do breakthrough cases mean the vaccine isn’t working? 

A. Absolutely not. None of the early trials claimed the vaccines would be 100% effective. Also, when the trials were conducted, masking was still required. It was only a few months ago that mask mandates were lifted, including in our area. We are seeing the effectiveness of the vaccine in real time, minus the effects of the mask, against the delta variant. The COVID vaccines are still very effective. 

Q. When should you be tested if you are vaccinated?

A. Centers for Disease Control and Prevention (CDC) guidelines tell us that if a fully vaccinated person is exposed to someone with COVID and that exposure is deemed high-risk (meaning within 6 feet for more than 15 minutes), that person should get tested. The timing of the test is important. You should be tested within three to five days of the exposure. If you are tested too soon, you may get a false negative. Beyond that, if you’re exposed and you have symptoms, you should get tested again. 

town hall recap

Delta Variant and How It's Changing the COVID-19 Landscape

Timothy Friel, MD, Chair, Department of Medicine, Infectious Diseases for Lehigh Valley Health Network (LVHN) and Alex Benjamin, MD, LVHN Infection Control Officer, answer your questions about COVID-19 and delta variant

Q. If you are fully vaccinated and test positive for COVID, what should you do?

A. If you are fully vaccinated and test positive you should isolate.

Keep in mind, if you have symptoms of COVID and you are fully vaccinated, you might be a candidate for monoclonal antibody treatment. Monoclonal antibodies are synthetic antibodies against COVID that can be administered as a one-time dose, either intravenously or subcutaneously. Monoclonal antibody treatment has been proven to be effective against COVID, including delta variant, so contact your primary care physician to learn more. 

Q. Will third shots (or booster shots) help prevent breakthrough infections? 

A. Hopefully. Pfizer has submitted data to the FDA regarding the effectiveness of an additional dose of vaccine, and we should hear shortly on whether a third dose will be approved for the general public. 

For more information about COVID-19, visit

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