The U.S. seems to be losing track of COVID-19 as cases remain massively undercounted, in part due to the rise of at-home testing.

Researchers at Boston Children’s Hospital and survey company Momentive found that in the week ending April 16, most positive COVID cases were detected by at-home rapid tests, a first for the U.S.

At-home tests are finally widely available as Dr. Anthony Fauci on Tuesday declared the U.S. “out of the pandemic phase” of COVID-19. Home tests often are an easier choice for patients, John Brownstein, chief innovation officer at Boston Children’s Hospital, said.

“But it’s not better for public health, because public-health data relies on detailed reporting,” Brownstein told Time magazine.

For now, there is no centralized system in the U.S. for people to report their at-home test results.

The challenge of reporting an accurate count of positive COVID cases is hardly new, though.

“We’ve had undercounting throughout the whole pandemic, right? And that has always been an issue,” Dr. Ashish Jha, the White House COVID-19 coordinator, told the “Today” show on NBC earlier this month.

It’s also an issue experienced by many countries, not just the U.S.

Dr. Tedros Adhanom Ghebreyesus, the World Health Organization’s director-general, welcomed the decline in reported cases and deaths. He said the agency recorded the lowest weekly total in COVID-related deaths since March 2020, but warned the emergence of a new, dangerous variant is still possible.

“As many countries reduce testing, WHO is receiving less and less information about transmission and sequencing,” Adhanom Ghebreyesus said Tuesday. “This makes us increasingly blind to patterns of transmission and evolution. But this virus won’t go away just because countries stop looking for it.”

Adhanom Ghebreyesus added we are still studying long-term consequences for people who contract the virus.

“When it comes to a deadly virus, ignorance is not bliss,” he warned.

Meanwhile, Fauci, director of the National Institute of Allergy and Infectious Diseases, told PBS NewsHour on Tuesday that the U.S. is no longer seeing record-high numbers of cases, deaths and hospitalizations.

The E.U. said Wednesday it is moving from the emergency phase of COVID, but urged countries to increase testing.

“Moving from emergency to more coordination will be essential to be ready for new outbreaks and variants,” the European Commission said in a tweet.

In England, the government ended a universal program offering people free rapid tests on April 1. Rapid tests are now available to buy, but results cannot be reported on the government website, according to the BBC.

The U.K. government says it is following a “living with COVID” approach. But Dr. Stephen Griffin, virologist at the School of Medicine at the University of Leeds, said the government is ignoring the prevalence of the virus, which he called “a mistake.”

“By not understanding how prevalent things are, people aren’t going to react to it,” Griffin told HuffPost. “And the more that we don’t hear about it, the further away from people’s minds it is.”

Griffin also warned about the difficulties of identifying future variants of concern.

“By doing less sequencing, you’re less likely to pick up those variants which might be coming in,” Griffin said. “And of course, the U.K. contributes massively to the global surveillance operation. So again, if we’re not doing that, there’s less awareness on the whole, of what’s going on globally.”