One voice after another called out the names of the 169 people just released by the U.S. Border Patrol. The migrants rose from their folding chairs in the clinic warehouse and walked over to a table of blue-robed workers, wiping their mouths.

That February morning, all but two Cuban women tested negative for COVID-19.They were quarantined in motel rooms while other immigrants boarded chartered vehicles to Phoenix Sky Harbor International Airport to fly across the U.S.

They were seven of 5,301 tests conducted by the Border Health Regional Center near Yuma, Arizona, on released immigrants last month that came back positive — a test rate of 0.1 percent

COVID-19 rates among migrants crossing the border from Mexico are falling as the Biden administration faces a Tuesday deadline to end or extend sweeping asylum restrictions aimed at limiting the spread of the virus. Since March 2020, the lower rates have raised more questions about the scientific basis of the public health order that has resulted in immigrants being deported from the United States more than 1.7 million times without a chance to apply for asylum.

While there is no overall rate of immigration, illegal crossing tests in several major corridors suggest it is well below levels that have raised concerns among U.S. officials.

In California, 54 of 2,877 immigrants tested positive in the first two weeks of March, according to the state Department of Social Services. The ratio was just 1.9%, down from a peak of 28.2% on Jan. 8.

In Pima County, Arizona, which includes Tucson, the seven-day positivity rate for immigrants did not exceed 1.3 percent in early March and fell to 0.9 percent on March 10. The 7-day positivity rate exceeded 5% in just two days. last three months of last year. Then, as the omicron variant spread, it surged into double digits for much of January, peaking at 19.2% on January 12, and dipping below 5% on February 12.

McCarran, Texas, the largest city in the busiest illegal border crossing corridor, has a higher percentage of immigrants — 9.2% on March 2 — but it’s also declining, and has remained below the general population. Of the 24 border counties, only two have a high percentage of their total population: Hidalgo, which includes McCarran, and Yuma, Arizona.

McCarran’s immigration rate peaked at 20.8 per cent in the last week of January, double the rate of the general population. It bottomed out at 1.4% in the last week of November, when the total population was 6.2%.

As the mask ban is lifted, the Centers for Disease Control and Prevention is under increasing pressure to fully restore asylum by ending Section 42, named after the Public Health Act of 1944. Critics say it’s an excuse to evade asylum obligations under U.S. law and international treaties.

Justice Justin Walker of the federal appeals court in Washington wrote this month that “it is unclear whether the CDC’s order has any effect on public health.” Walker, appointed by President Donald Trump, noted that the Biden administration has not provided detailed evidence to support the restrictions.

“The CDC’s order looks in some ways like a relic of an era of no vaccine, lack of testing, little treatment and little certainty,” Walker wrote for a three-judge panel.

Dr. Rochelle Walensky, director of the CDC, noted that rates fell when she ended asylum restrictions on unaccompanied child immigration on March 11, while retaining those restrictions for adults and families with children. In August, U.S. border authorities began testing children traveling alone in the busiest areas: the positivity rate fell from a high of nearly 20 percent in early February to 6 percent in the first week of March.

The White House and the Department of Homeland Security said decisions on Section 42 were made by the CDC. Walensky told reporters on Wednesday that the CDC is reviewing the data ahead of a deadline next week, noting that its two-month update in late January was near the peak of the omicron variant.

The scientific arguments for Title 42 were met with skepticism from the start.

The Associated Press reported in 2020 that Vice President Mike Pence directed the CDC to use its emergency powers, rebutting claims by agency scientists who said there was no evidence it would slow the spread of the coronavirus.

Anne Schuchat, the CDC’s No. 2 until last May, told lawmakers after she left that asylum restrictions were introduced without a basis as a public health measure.

“Most of the evidence at the time did not support this policy proposal,” she said.

Title 42 also has supporters. “There should be no objection that current immigration policy should focus on preventing the spread of COVID-19,” U.S. District Judge Mark Pittman of Fort Worth, Texas, said in his ruling on the order this month.

Despite mass deportations under Section 42, the United States processed more than 2.8 million cases under normal immigration law, allowing people to seek asylum.

Migrants are often released to NGOs and ordered to appear in immigration court later, as costs and strained diplomatic relations limit deportations to many countries. Team testing for COVID-19.

In El Paso, the positivity rate dropped to about 2 percent of the roughly 175 immigrants the Annunciation House tested a day in early March, said director Ruben Garcia. At the height of the omicron variant, the positivity rate was closer to 40 percent, he said.

In Arizona, the two-country health regional center’s monthly rate peaked at 3 percent last year.

Still, its president, Amanda Aguirre, remains cautious about lifting Article 42.

“My concern is that anytime we’re going to see new variants entering the space,” she said.

The Val Verde Frontier Humanitarian Coalition, which tests migrants in Texas’ busy Del Rio area, said it has gone on for weeks without a single positive result.

“There was one positive yesterday, one positive today — one of hundreds of tests,” the group wrote last week in response to questions.