You Can't Get a Test for the Delta Variant—But You Don't Need One Anyway, According to Doctors


For a little while in early summer, it looked like we were finally beating the COVID-19 pandemic. And then the Delta variant showed up.

The highly transmissible variant has quickly become not only the dominant variant in the US, but almost the only variant in the country. Delta went from causing just 2% of COVID-19 cases in mid-May to 98% of cases as of August 14, according to data from the Centers for Disease Control and Prevention (CDC).

Is There a Test for the Delta Variant? , Close up of doctor with sample from sick woman. Selective focus on sample. Is There a Test for the Delta Variant? , Close up of doctor with sample from sick woman. Selective focus on sample.

What is the Delta variant, again?

The Delta variant, aka B.1.617.2, was originally detected in India in December 2020, per the CDC. It's a mutation of B.1.617, the so-called "double mutant" strain that made headlines back in April.

The Delta variant has several mutations on the spike protein of SARS-CoV-2, which helps it spread more easily than the original SARS-CoV-2. The CDC specifically says that this variant is more easily spread and poses a "potential reduction" in the effectiveness of the COVID-19 vaccine. It also may make some monoclonal antibody treatments less effective against the virus.

Right now, the Delta variant makes up 98% of COVID-19 cases in the US. "If you've gotten COVID recently, you've gotten it from the Delta variant," William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Health.

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So is there a test for the Delta variant?

This is where things get a little tricky. Technically, there is a test for the Delta variant—but it's not something you or your doctor has access to. "There is no commercial test for the Delta variant," Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, tells Health. Instead, what happens is that a "selected sample" of positive polymerase chain reaction (PCR) tests are "further studied to look for the characteristic mutations of the Delta variant," Dr. Adalja explains.

The CDC has a national SARS-CoV-2 genomic surveillance program that works to ID and track down variants of the virus that are circulating in the US. Under this program, the CDC regularly receives samples from state health departments and other public health agencies for genetic sequencing, further characterization, and evaluation, the CDC explains. The system processes 750 samples a week and then calculates a slew of information, including what percentage of cases are due to certain variants.

"This sequencing is only done at specialty labs," Thomas Russo, MD, professor and chief of infectious disease at the University at Buffalo in New York, tells Health.

Basically, there's a small chance that your positive COVID-19 test could be sent off to the CDC for genomic sequencing, but you wouldn't know or find out about it anyway.

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Doctors say you really don’t need to be tested for the Delta variant

"At the end of the day, it doesn't matter," Dr. Russo says. "Whether you're infected with the Delta variant or another one, it's not going to affect how you manage the illness."

Dr. Schaffner agrees. "We don't have the capacity to test everyone for the Delta variant now, and we don't need to," he says.

Ultimately, knowing which positive COVID-19 tests are from the Delta variant is for public health surveillance and tracking, Dr. Russo says. "It's important from a public health point of view, but from a personal point of view…there's no significant reason that you need to know which variant you have," he says.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDCWHO, and their local public health department as resources.

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