New research from the journal Centers for Disease Control and Prevention (CDC) Emerging infectious diseases analyzed a case showing in-flight transmission of acute respiratory syndrome (SARS-CoV-2) coronavirus 2 although passengers were tested before departing for New Zealand.
Since the first wave of coronavirus, New Zealand has had an exceptional response to the pandemic with a managed isolation and quarantine system for people entering the country. Restrictions were also extended to include COVID-19 testing to people on the third and twelfth day of quarantine.
The world currently has more than 114 million cases worldwide and more than 2.53 million deaths. New Zealand has some of the lowest cases in the world reporting approximately 2,378 cases and 26 deaths.
The study “Genomic evidence of in-flight transmission of SARS-CoV-2 despite pre-departure testing” may help scientists and public health officials further understand the exact risk of coronavirus transmission on long flights. The international research team, led by Tara Swadi of the New Zealand Ministry of Health, writes:
“Combined, these data present a likely scenario of> 4 SARS-CoV-2 transmission events during a long-haul flight from Dubai to Auckland. These transmission events occurred despite the use of masks and gloves during the flight. Then there was another transmission between fellow travelers after the flight, at an MIQ facility. “
Details on the transmission of the COVID flight between seven passengers
The team gathered data from cases of a coronavirus outbreak on a plane on September 29, 2020, arriving from Dubai, UAE, to Auckland, New Zealand. During isolation and quarantine managed for 14 days, 7 people tested positive for SARS-CoV-2. The researchers collected data from the Ministry of Health’s collection for surveillance of the epidemic.
The 7 SARS-CoV-2 infected passengers came from 5 different countries and 5 were negative on a scale in Malaysia. The 7 passengers were sitting in 4 rows of each other during an 18 hour flight. During the flight and before leaving Dubai airport, the use of masks was optional. Five of the seven infected passengers wore masks and gloves on the plane, while 2 did not.
countries of origin for 7 passengers who tested positive for acute respiratory coronavirus 2 infection after traveling on the same flight (EK448) from Dubai, UAE to Auckland, New Zealand, with a refueling stop in Kuala Lumpur, Malaysia, on September 29, 2020. The asterisks indicate where 6 other genetically identical genomes have been reported.
Genomic data of SARS-CoV-2
The researchers performed complete genome sequencing on test samples from the 7 SARS-CoV-2 positive patients. They found that the sequences were genetically identical and, with the exception of one passenger mutation, all SARS-CoV-2 samples came from the B.1 lineage.
The researchers compared the 7 genomes with the International Database (GISAID) and also found 6 identical genomes, with 4 from Switzerland and 2 from the UK.
Source tracking
According to the results, the team predicts that two passengers were the source of the infection. These passengers had traveled together from Switzerland and had been negative three days before leaving the country. One of these passengers was the first to report symptoms of COVID-19 infection on October 1., with a positive SARS-CoV-2 test the next day.
In addition, they anticipate that four passengers became infected during the flight and one passenger became infected while in mandatory quarantine.
Seat arrangement (Boeing 777-300ER) for 7 passengers who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on flight EK448 from Dubai, UAE, Auckland, New Zealand, with a refueling stop in Kuala Lumpur, Malaysia, on September 29, 2020. Passengers F and G exchanged seats in row 24. The open circles represent nearby passengers who denied SARS-CoV-2 on 3 and 12 while they were isolated and quarantined. The remaining seats shown remained empty.
Limitations in genomic surveillance present difficulties in finding the source of transmission
However, researchers suggest that limited global sequencing data make it difficult to reduce the source of the SARS-CoV-2 outbreak in the aircraft.
“These results coincided with the introduction of viruses on the plane from Switzerland by passenger A, B or both. However, accurately identifying the source of this outbreak can be hampered by substantial biases and gaps in the global sequencing data; therefore, we cannot explicitly exclude passenger C as a source “.
There is also the possibility of an alternative exhibition event, such as the SARS-CoV-2 broadcast at Dubai Airport before boarding. Although they suggest that nearby seats make in-flight transmission a likely option.
“While not definitive, these findings underscore the value of considering all international passengers arriving in New Zealand as potentially infected with SARS-CoV-2, even if pre-departure tests were performed, followed the distancing and social spacing and protected personal equipment used during the flight. “