New survey by the journal Centers for Disease Control and Prevention (CDC) Emerging infectious diseases analyzed a case that showed the in-flight transmission of acute respiratory syndrome coronavirus 2 (SARS-CoV-2), despite passengers being tested before leaving for New Zealand.
Since the first wave of coronavirus, New Zealand has had an exceptional response to the pandemic with a controlled isolation and quarantine system for people entering the country. The restrictions also expanded to include testing people for COVID-19 in the third and twelfth quarantine days.
The world currently has more than 114 million global cases 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 “SARS-CoV-2 genomic evidence of in-flight transmission, despite pre-departure testing,” may help scientists and public health officials to better 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 for> 4 SARS-CoV-2 transmission events during a long-haul flight from Dubai to Auckland. These transmission events occurred despite the reported use of masks and gloves during the flight. Subsequent transmission between fellow travelers occurred after the flight, in an MIQ facility. “
Details on the transmission of the COVID flight between seven passengers
The team collected case data from a coronavirus outbreak on a plane on September 29, 2020, arriving from Dubai, United Arab Emirates, to Auckland, New Zealand. During the 14-day isolation and managed quarantine, 7 people tested positive for SARS-CoV-2. The researchers collected data from the Ministry of Health’s collection for epidemic surveillance.
All 7 passengers infected with SARS-CoV-2 came from 5 different countries, and 5 tested negative on a scale in Malaysia. All 7 passengers were seated 4 rows apart from each other during an 18-hour flight. During the flight and before leaving Dubai airport, wearing a mask was optional. Five of the 7 infected passengers wore masks and gloves while on the plane, while 2 did not.
travel source contracts for 7 passengers who tested positive for coronavirus 2 infection with severe acute respiratory syndrome after traveling on the same flight (EK448) from Dubai, United Arab Emirates, to Auckland, New Zealand, with a refueling stop in Kuala Lumpur, Malaysia, 29 September 2020. Asterisks indicate where 6 other genetically identical genomes have been reported.
Genomic data SARS-CoV-2
The researchers performed the complete genome sequencing on the 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 strain B.1.
The researchers then compared the 7 genomes with the international database (GISAID), which also found 6 identical genomes, 4 from Switzerland and 2 from the United Kingdom.
Tracing the source
Based on the results, the team predicts that 2 passengers were the source of the infection. These passengers traveled together from Switzerland and tested 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 result the next day.
In addition, they predict that 4 passengers were infected during the flight and one passenger was infected during the mandatory quarantine.
Seats (Boeing 777-300ER) for 7 passengers with a positive test for infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on flight EK448 from Dubai, United Arab Emirates, to Auckland, New Zealand, with refueling stop at Kuala Lumpur, Malaysia, on September 29, 2020. Passengers F and G switched seats in row 24. The open circles represent nearby passengers who were negative for SARS-CoV-2 on days 3 and 12 while in isolation and managed quarantine. All other seats shown remained empty.
Limitations in genomic surveillance make it difficult to find the source of transmission
However, the researchers suggest that limited global sequencing data makes it difficult to restrict the origin of the SARS-CoV-2 outbreak on the plane.
“These findings were consistent with the introduction of the virus on the Swiss plane by passenger A, B or both. However, the precise identification of the source of this outbreak can be prevented by substantial biases and gaps in the global sequencing data; therefore, we cannot explicitly exclude passenger C as the source. “
There is also the possibility of an alternative exhibition event, such as the transmission of SARS-CoV-2 at Dubai airport prior to departure. However, they suggest that the nearby seats make transmission during the flight a likely option.
“While these findings are not definitive, they underscore the value of considering all international passengers arriving in New Zealand as potentially infected with SARS-CoV-2, even if the test before departure was carried out, social detachment and spacing were followed, and personal protective equipment was used during the flight. “