The vaccine is huge. And here’s how you can end the pandemic even sooner.

As Utahns wait to be vaccinated, testing allows health officials to find new cases and stop the virus from spreading.

(Trent Nelson | The Salt Lake Tribune) Sgt. 1st Class Sean Conorich working at a COVID-19 testing site run by the Utah National Guard at the Utah State Fairpark in Salt Lake City on Thursday, Feb. 25, 2021.

Nearly a year ago, anxious crowds pressed into Utah’s hospitals in hopes of being tested for the coronavirus, while testing supplies were so scarce that health officials told Utahns not to even ask for a test unless they were extremely ill.

The lack of aggressive, widespread early testing — with a flawed first federal test, regulation that slowed the release of alternatives and other factors — arguably cost Utah and the nation the chance to rein in the virus last spring.

Now testing is in the spotlight again — as Utah uses testing and tracing to bat cleanup against new outbreaks while cases drop and the number of vaccinated residents grows.

Gov. Spencer Cox is urging Utahns to get tested, whether they’re sick or not. There are pop-up sites for rapid antigen testing each week in multiple counties, and at least some hospitals no longer require a doctor’s referral to be tested for COVID-19. And the state once again is trying to get Utahns to sign up for phone alerts that will notify users that someone they have had contact with has tested positive.

Here’s what we know about the state’s renewed push for testing, and what it means for you.

A few months ago it was hard to get a coronavirus test even through my health care provider; now there are “rapid antigen” testing sites all over the state. Who is doing all of these tests?

The state in early January began offering “rapid antigen” tests during weekly one- and two-day pop-up clinics at dozens of sites around Utah. Most of those tests have been conducted by the Utah Department of Health, at sites also staffed by Utah National Guard troops, said UDOH spokesman Tom Hudachko.

Other sites have been handled by Nomi Health, the Orem health care technology company that operates TestUtah under a contract with the state. Former Gov. Gary Herbert first announced that TestUtah would conduct asymptomatic testing statewide starting in September, when rapid tests became widely available. According to testing data obtained by The Salt Lake Tribune, TestUtah appears to have performed fewer than 1 in 10 of the coronavirus tests in Utah from September to January.

[Read more: Exclusive: TestUtah’s COVID-19 testing costs the state more than other sites, analysis shows]

Since the pandemic began, about 3.9 million coronavirus tests have been performed in Utah, on about 2.2 million people. The bulk of testing has been done by health care systems, with about 1.1 million by Intermountain Healthcare and more than 400,000 by University of Utah Health. TestUtah had conducted about 250,000 tests as of the end of January, and the Utah National Guard and UDOH teams had done about 290,000 as of mid-February, Hudachko said.

Why is the state promoting more testing now, right when cases are declining? Should testing have been more widespread when cases were peaking in November?

The state launched the antigen testing sites in January to quickly identify outbreaks after holiday gatherings, especially as schools reopened, Hudachko said — though he added that testing “has not become any more, or less, central to the state’s response.”

“Testing as many people as possible has always been a key strategy, and always will be,” he wrote in an email. “... What has changed are the tactics available to us to achieve this strategy: rapid testing, mobile testing, in-school testing, community surge testing, etc.”

When the pandemic began, state epidemiologist Dr. Angela Dunn noted testing can be most advantageous when there are fewer cases, saying at the time: “The benefit of communitywide surveillance is ... you’re able to really get an early sense of where the virus is at.”

And while testing is always crucial to ensure those who are infected know to isolate, contact tracing may become less and less practical as more cases are confirmed. As case numbers escalated through the fall, some Utah health departments had to scale back contact tracing efforts, calling fewer of each infected person’s contacts and asking patients and employers to try to notify others who might be at risk.

“When a contact tracer gets about five new cases every day or so, it’s very hard to stay on top of it,” Salt Lake County epidemiologist Annie George said in October. “It reaches a point where it’s not effective because … it doesn’t do you any good if you’re calling them after they’ve already been off of quarantine for a while.”

So is Utah actually testing more people now that it is offering rapid testing to anyone who wants it?

No, but it does appear to be identifying a significantly bigger share of infected Utahns.

Coronavirus testing numbers soared in late November, as case numbers also were peaking. In the week leading up to Thanksgiving, Utah was testing more than 25,000 people a day — and testing rose to that level again in early January, as students returned to school after winter holidays. In recent weeks, Utah has been averaging about 15,000 tests per day.

However, the percent of tests coming back positive has declined sharply since rapid testing began. The higher that percentage is, the more likely it is that a lot of cases are going undetected and infected Utahns are carrying and spreading the virus unwittingly.

In early January, nearly a third of all tests were positive; as of Thursday, that figure was down to about 10%, even with thousands fewer people being tested each day.

That’s still a long way off from numbers that would show testing has captured enough cases that the virus is probably not spreading undetected in the community. In June, when the percent positivity was around 8%, Dunn said that a rate of 3% would indicate “that we really have this under control.”

Testing has risen and fallen alongside the number of cases, and with cases dropping in recent weeks, “we have also seen testing numbers decline,” Hudachko said.

But to prevent community transmission, Cox said, Utahns shouldn’t wait for symptoms to arise.

“We ... really want to highlight that testing is still the very best way to identify positive cases so that people can isolate and stop transmitting the virus to others,” Cox said in a recent news briefing. “... Please, please don’t hesitate to get tested.”