Airlines have been pushing preflight Covid-19 PCR testing as a way to open up international travel safely, and there have been separate studies that have concluded that inflight infections are sporadic.
A study done in New Zealand has come to a different conclusion. An asymptomatic but highly contagious passenger, who had tested negative preflight, ended up infecting 5% of the flight’s passengers (4 infections – 86 passengers).
The researchers sequenced the DNA of the Covid-19 virus the passengers had and found out that they were basically the same mutation (Swiss), although travelers had originated from several countries.
Some of the infected passengers claimed that they had masks on for the duration of the flight that might have been impossible due to its length (18+ hours, including a technical stop in Kuala Lumpur).
Here’s how the passengers got infected:
Here’s the study:
These research papers and studies are sometimes difficult to read due to the jargon used. Still, this one flows nicely even for non-scientific people and is a worthwhile read for everyone who travels in the current environment.
One of the reasons why the asymptomatic person might have been able to infect so many others on this flight was its duration.
It also questions the usefulness of preflight testing that is usually done 72 to 48 hours before departure and those done at the time of arrival.
You may have been recently infected that won’t show up on the test, OR you may get infected between when the test was taken and when you board the flight. You can be highly contagious even when you have absolutely no symptoms at all.
The only way to catch all the cases is mandatory quarantine like the one in New Zealand. We can argue, however, whether 14-day quarantine is too long. You could perhaps catch most if not all infections by doing a test at the five-day mark.
I personally went through coronavirus infection and obviously survived it, or you wouldn’t be reading this in Brazil. More of that tomorrow.