Cluster of Covid-19 cases linked to flight sparks debate among health experts

Speaking from the hospital, Ms Fathima said she feared her family contracted the infections during the April 3 trip, despite wearing masks almost all the time and avoiding using the toilet on board.

Some passengers – including one in the same row – repeatedly coughed during the six-hour flight, people took off face masks to eat, and some parents had their crying children up and down the aisle, he said. she declared.

The airline and the chartered flight organizers told the Wall Street Journal that they had done everything to minimize the potential transmission.

Vistara airline, run by Tata SIA Airlines Ltd., said it guarantees “strict adherence to all guidelines issued by authorities in India and destination countries for all flights.”

Experts say air travel is generally safe. But even with the best precautions, there are risks associated, as coronavirus cases continue to skyrocket in parts of the world and with young children not yet eligible for vaccination.

There could, for example, be passengers carrying particularly virulent strains of the virus. Being well packaged, regardless of the quality of ventilation, puts some passengers on the path to potential infection with respiratory particles from people sitting nearby or on surfaces in the lavatory. And there is a risk that the virus will spread at airports before and after the flight.

Health experts are examining other possibilities, including whether travelers were infected in quarantined hotels in Hong Kong after arriving, or whether India’s overburdened healthcare system failed to accurately detect cases before passengers left – although only four tested positive on arrival.

India is grappling with a surprising second wave of coronavirus infections. The country reported more than 332,000 new infections on Friday, the highest one-day tally in any country since the start of the pandemic. It would also be possible, according to epidemiologists, that some passengers of the plane are infected in the country after their test for the virus upstream.

Hong Kong on Tuesday suspended flights from India for two weeks and put India on the list of very high-risk countries for arrivals. The city has one of the most stringent testing, tracing and quarantine systems in the world, imposing 21 days of hotel quarantine on nearly all inbound international travelers and subjecting them to multiple rounds of Covid tests during the period. . This provides a more detailed overview of the infectious status of travelers. Most of the cases on the New Delhi flight were not discovered until days after the group landed in the city.

Scientists at the University of Hong Kong who work with the city’s health department are sequencing the genomes of the passenger group and examining the information to determine if they were infected on board.

Hong Kong-based GC Nanda & Sons Ltd., known as Nanda Travel, which organized the charter flight, said the Airbus A321neo plane was at 85% capacity, with 146 passengers and 7 infants.

All passengers produced evidence of a negative Covid-19 test from reputable labs taken within 72 hours of the plane’s take-off, the company said. Six passengers were denied boarding by the charter operator because their test result certificates did not meet the travel company’s standards.

Passengers were required to wear masks except when eating prepackaged meals. Alcohol wipes and hand sanitizer were provided.

“We are shocked by this,” said Poonam Nanda, director of Nanda Travel. “This theft appears to be an amazing outlier and we are all bewildered by these numbers.”

Of 29 charter flights the company has operated to bring stranded travelers back to Hong Kong in recent months, less than 1% of passengers have tested positive on arrival and on many flights there has been no later case, she said. The company will improve its protocols, such as requiring negative Covid-19 test certificates no later than 48 hours before departure on future flights, she said.

“The risks of air travel are usually quite manageable with staggered seats and constant mask use, especially when using the toilet,” said Siddharth Sridhar, clinical virologist in the Department of Microbiology at the University of Hong Kong.

Ventilation and air filtration further reduce the risk of virus transmission on airplanes, Dr Sridhar said. Still, many variables could have an impact, including whether people routinely wore masks on board, whether meals were served, how many toilets were operational and how many passengers were in single-family units, he said.

Locking the middle seat on planes can reduce the risk of coronavirus for passengers by 23% to 57%, a Centers for Disease Control and Prevention lab study published this month suggested. Despite this, most carriers in the United States have resumed selling tickets in the middle seat.

The real problem is how passengers comply with regulations, said Leo Poon, a professor at the School of Public Health at the University of Hong Kong. A study he co-authored last year showed that SARS-CoV-2 – the virus that causes Covid-19 – can be transmitted by air, highlighting the importance of continuing to fight infections.

Ms Fathima, who runs an import-export business in Hong Kong, said a connecting flight in the morning from Chennai to New Delhi and the diaper locker room at Hong Kong airport could also have been potential locations. where she, her husband, 8- a one-year-old daughter and a 2-year-old son contracted the virus.

“We were so careful when we were in India,” Ms. Fathima said, adding that the family had stayed at home for a week before traveling. “I never imagined I would catch the virus on the trip.”

Write to Natasha Khan at [email protected]