US mulls airline wastewater testing to track new variants amid Covid spike

As Covid-19
infections surge in China, the US Centers for Disease Control
and Prevention or CDC is considering sampling wastewater taken from
international aircraft to track any emerging new variants, the
agency told the Reuters news agency.

Such a policy would offer a better solution to tracking the
virus and slowing its entry into the United States than new
travel restrictions announced this week by the US and other
countries, which require mandatory negative Covid tests for travellers from China, Reuters reported on Thursday, quoting three infectious disease experts.

Travel restrictions, such as mandatory testing, have so far
failed to significantly curb the spread of Covid and function
largely as optics, said Dr. Michael Osterholm, an infectious
disease expert at the University of Minnesota.

“They seem to be essential from a political standpoint. I
think each government feels like they will be accused of not
doing enough to protect their citizens if they don’t do these,”
he said.

The United States this week also expanded its voluntary
genomic sequencing program at airports, adding Seattle and Los
Angeles to the programme. That brings the total number of airports
gathering information from positive tests to seven.

But experts said that may not provide a meaningful sample
size.

A better solution would be testing wastewater from airlines,
which would offer a clearer picture of how the virus is
mutating, given China’s lack of data transparency, said Dr Eric
Topol, a genomics expert and director of the Scripps Research
Translational Institute in La Jolla, California.

Getting wastewater off planes from China “would be a very
good tactic,” Topol said, adding that it’s important that the
United States upgrade its surveillance tactics “because of China
being so unwilling to share its genomic data.”

READ MORE: US to require negative Covid tests for visitors from China

‘Valuable wastewater surveillance’

China has said criticism of its Covid statistics is
groundless and downplayed the risk of new variants, saying it
expects mutations to be more infectious but less severe.

Still,
doubts over official Chinese data have prompted many places,
including the United States, Italy and Japan, to impose new
testing rules on Chinese visitors as Beijing lifted travel
controls.

Airplane wastewater analysis is among several options the CDC
is considering to help slow the introduction of new variants
into the United States from other countries, CDC spokesperson Kristen Nordlund said in an email.

The agency is grappling with a lack of transparency about
Covid in China after the country of 1.4 billion people abruptly
lifted strict Covid lockdowns and testing policies, unleashing
the virus into an undervaccinated and previously unexposed
population.

“Previous Covid-19 wastewater surveillance has shown to be a
valuable tool and airplane wastewater surveillance could
potentially be an option,” she wrote.

READ MORE: How various states used Covid-19 tech for highly invasive ‘surveillance’

‘Border closure won’t stop the spread’

French researchers reported in July that airplane wastewater
tests showed requiring negative Covid tests before international
flights does not protect countries from the spread of new
variants.

They found the Omicron variant in wastewater from two
commercial airplanes that flew from Ethiopia to France in
December 2021, even though passengers had been required to take
Covid tests before boarding.

California researchers reported in July that sampling of
community wastewater in San Diego detected the presence of the
Alpha, Delta, Epsilon and Omicron variants up to 14 days before
they started showing up on nasal swabs.

Osterholm and others said mandatory testing before travel to
the United States is unlikely to keep new variants out of the
country.

“Border closures or border testing really makes very little
difference. Maybe it slows it down by a few days,” he said,
because the virus is likely to spread worldwide, and could
infect people in Europe or elsewhere who may then bring it to
the United States.

David Dowdy, an infectious disease epidemiologist at Johns
Hopkins Bloomberg School of Public Health, said increasing
genomic surveillance is important, and wastewater sampling could
be helpful, but the testing takes time.

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

READ MORE: China’s Xi calls for steps to ‘protect’ lives amid new Covid-19 wave