Do PCR tests detect COVID variants? Do vaccines prevent severe illness caused by COVID variants?

Local 4′s Dr. Frank McGeorge answers your virus variant questions

DETROIT – Information is critical when it comes to the coronavirus and the vaccines, and it can sometimes be challenging to find the answers to your specific questions.

Our resident Dr. Frank McGeorge is here to help, answering your questions about COVID-19, vaccines, the vaccination process and more. (You can submit your questions below.)

Read: More answers to questions about coronavirus

Below, Dr. McGeorge is answering questions from viewers about COVID-19 variants.


When we talk about COVID-19 variants, you’ll often hear two different terms used: a variant of “interest,” and a variant of “concern.”

There is a difference between the two: A variant of interest is one that is being monitored because it could have important changes or distinctions. A variant of concern is one that has demonstrated a problematic change in its ability to spread, the severity of illness it produces or its ability to evade immunity or medical treatments.

There are currently five variants of concern, and all of them have been identified in Michigan. Although this is not a variant of concern, even the COVID variant spreading across India has been detected in our state recently.

Let’s answer some of your questions about COVID-19 variants:

Having just gotten out of the hospital with COVD, I was told that they couldn’t say if I had contracted a variant or not. Do they test for variants? And if so, how?

Testing for variants requires a specimen to be sent to a state lab where a process called “genome sequencing” is carried out. Basically, they map out all 30,000 pieces of the genetic code for the virus that is found in the sample.

This process is not routinely done on all COVID-19 tests, and is generally reserved for outbreak investigations or cases with unusual symptoms or situations.

Does the PCR test check for virus variants? If not, does that mean if you have symptoms but get a negative COVID-19 result, that you may have one of the variants?

So far for COVID-19 variants identified in the U.S., if you are infected with one of them, your PCR test will come back positive.

In fact, certain PCR tests can also indirectly detect one of the COVID variants, because that variant causes the test to be positive in an unusual way.

Longer term, it is possible that a virus variant could emerge that might be more difficult to be detected by some PCR tests.

Could delaying your second dose beyond the recommended time period raise your risk for contracting a COVID variant?

Delaying your second COVID-19 vaccine dose won’t specifically make you more susceptible to virus variants, but your overall immunity won’t be what it could be without both doses of the two-shot vaccines. You should definitely get the second dose.

My husband and I have received both doses of the Pfizer vaccine. Should we be concerned about getting the variants? Would the vaccine prevent serious illness and hospitalization caused by the variants?

At this point, COVID vaccines are your best protection against the virus.

The vaccines appear to protect people from those circulating variants, particularly against experiencing severe disease.

That being said, there is still more research needed on vaccine efficacy against the different COVID variants. We don’t know what the future will hold regarding new variants.

What is the chance that a COVID variant will evolve and render all of the vaccines thus far ineffective?

It is not likely that the existing COVID-19 vaccines would become ineffective -- but they could become less effective, depending on factors of a new variant like its virulence and transmissibility.

It is possible that an additional booster vaccine would be recommended to better protect you against a hypothetical future variant, but hopefully that either never happens or is a long way off.


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Since the coronavirus pandemic began, Dr. McGeorge has been keeping viewers up-to-date and informed on all fronts. He’s been answering your questions about the vaccine, the vaccination process and more.

Questions about coronavirus? Ask Dr. McGeorge


About the Authors

Dr. McGeorge can be seen on Local 4 News helping Metro Detroiters with health concerns when he isn't helping save lives in the emergency room at Henry Ford Hospital.

Cassidy Johncox is a senior digital news editor covering stories across the spectrum, with a special focus on politics and community issues.

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