CDC Considers Testing Wastewater on Airliners as China Lifts COVID-19 Travel Restrictions

Travelers sit at the arrival hall of the Hong Kong International Airport in Hong Kong on Dec. 30, 2022. (Anthony Kwan/Getty Images)

The Centers for Disease Control and Prevention (CDC) will consider sampling wastewater taken from international flights to track any emerging new variants coming from China.

The wastewater test policy is one of several options the CDC is considering to help slow the spread of new variants from other countries, the agency told Reuters.

Countries around the world are enacting testing requirements after the Chinese Communist Party (CCP) announced an ease in border restrictions and international travel beginning Jan. 8.

The CDC announced on Dec. 28 that it will implement a negative COVID-19 test requirement for passengers flying to the United States from China, Hong Kong, and Macau while infections surge there.

A lack of transparency regarding reliable medical data from Beijing has raised many concerns regarding standard CDC testing policies.

World Prepares for Travelers

Other countries, like Italy and Japan, have instituted similar travel restrictions requiring negative COVID-19 tests for travelers coming from China.

U.S. testing requirements for travelers from China will begin on Jan. 5. The CDC also said that it would “periodically reassess” and reinstate testing requirements as required.

Passengers over the age of 2 must show a negative result from either a PCR or rapid antigen test performed or monitored by a licensed health professional within two days of departure, the CDC said.

Visitors could alternatively provide a document of recovery if they tested positive more than 10 days before their flight.

Beijing’s Lack of Transparency Concerns Health Analysts

The surge in cases in China is difficult for foreign observers to validate because of the CCP’s decision to restrict access to public health data and its redefining of pandemic-related fatalities to those caused by respiratory failure.

Carlos del Rio, president of the Infectious Diseases Society of America, commented on the situation in a Twitter post.

“What needs to be clear is what is the objective of this policy and how do we evaluate it. Also, if we are not trusting information coming out of china why would we trust the testing they will implement for passengers fling [sic] out of China?” del Rio wrote.

The CDC also expanded its voluntary genomic sequencing program at airports this week, adding Seattle and Los Angeles—which are major points of entry from China—to the program.

This will bring the total number of U.S. airports gathering information from positive COVID-19 tests to seven, but some scientists say this does not provide a meaningful sample size.

The CCP has said that most criticism of its virus statistics was groundless and that there was little risk of new variants. Beijing officials claim that any future virus mutations would likely be more infectious, but less severe over time.

Wastewater Testing Effective at Detecting Variants

CDC spokeswoman Kristen Nordlund told Reuters that the CDC is burdened with a lack of transparency about the virus from Beijing, after it terminated its strict lockdown and testing policies, and wastewater testing is one option the agency is considering.

“Previous COVID-19 wastewater surveillance has shown to be a valuable tool and airplane wastewater surveillance could potentially be an option,” Nordlund said.

In July, researchers in California detected different variants of the CCP virus in samples of community wastewater in San Diego at least 14 days before the variants began showing up on nasal swabs, Reuters reported.

The same month, scientists in France reported that airplane wastewater tests proved that requiring negative pre-boarding COVID-19 tests did not protect countries from the spread of new variants.

The French team found the omicron variant in wastewater on two flights from Ethiopia to France in December 2021, despite every passenger being screened with tests before boarding.

Monitoring the genetic development of the virus and sampling wastewater could be helpful, but testing takes time, David Dowdy, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, told Reuters.

“I think we should be cautious in how much we expect those data will be able to truly inform our ability to respond,” he noted.