Experts say it's 'meaningless' to compare case counts, positivity rates from the current COVID-19 wave driven by the Omicron BA.5 subvariant to earlier spikes

COVID-19 rapid test — Rapid test device for COVID-19.
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Comparing current COVID-19 data like positivity rate to prior waves in the pandemic is now "meaningless," experts said.
The widespread use of rapid at-home testing has skewed the data, the experts said.
Experts told Insider that hospitalization rates are a more relevant metric to watch.

Comparing current COVID-19 data — like case counts and positivity rate — to earlier points in the pandemic is now "meaningless" thanks to the widespread use of rapid at-home testing and the underreporting of results, public health experts told Insider.

"It's an invalid comparison. They're not telling you the same type of information," infectious disease expert Dr. Amesh Adalja, a senior scholar at Johns Hopkins Center for Health Security, said.

In recent weeks, the highly infectious Omicron BA.5 subvariant has become the dominant COVID-19 strain in the US, and is now estimated to account for more than 60% of all cases, according to the Centers for Disease Control.

But comparing this wave to previous surges in infections isn't a fair comparison since the data being collected has changed so drastically, said Dr. Rachael Piltch-Loeb, an associate research scientist at the NYU School of Global Public Health.

Though the current data is "accurately capturing what's happening … what's going into the data is not the same as what was going into the data previously," Piltch-Loeb said.

Adalja explained that data showing spikes in the test positivity percent — which was used by local health officials to guide the COVID-19 response — "is basically a meaningless number at this point in the pandemic because most tests are taken at home and they're not factored into that."

Dr. Anthony Fauci, the nation's top infectious disease expert, confirmed during a briefing on Tuesday that the CDC's COVID-19 case counts are an "underestimate."

"There are many people getting infected with mild to moderate symptoms who do home testing and do not report it," said Fauci.

Piltch-Loeb noted that during the initial coronavirus peak in April 2020 — when the nation's weekly positivity rate soared to 21% — more people who were both symptomatic and asymptomatic were seeking out public testing because there was no other way to get tested for COVID-19 as home testing did not exist.

Current data from the CDC showing coronavirus case counts and high percent positivity rates "is just a small piece of the puzzle," Piltch-Loeb said.

"This is a mental pretzel about what the charts we see mean now," added Piltch-Loeb.

Experts told Insider that hospitalization rates are a more relevant metric to watch.

National COVID-19 hospitalizations have steadily increased since early April 2022 with now more than 5,000 new admissions daily, according to the latest CDC data. Adalja said hospital capacity is also an "important metric" to watch.

Despite the rising numbers, vaccines and booster shots are still effective at preventing serious illness and death caused by the newest subvariant, even if the new subvariant is more likely to reinfect.

"The goal is to make sure we are preventing severe illness, hospitalization and death — that we're not seeing hospitals get overwhelmed," Adalja said. "And I don't think that BA.5, irrespective of its ability to cause cases, is going to be able to threaten the hospital capacity the way the virus once could."

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