Domestic Flight Vaccine Mandates: Where Is the Data?

Bloomberg is a privately owned business and economic news agency. “Connecting decision makers to a dynamic network of information, people and ideas. Bloomberg quickly and accurately delivers business and financial information, news and insight around the world.”

But in their Bloomberg Prognosis Coronavirus Daily they frequently stretch the truth to fit a pre-defined narrative.  In today’s Coronavirus Daily email newsletter, the lead article was:

Here is what they said in the short article: “Aircraft passengers are twice or even three times more likely to catch Covid-19 during a flight since the emergence of the omicron variant, according to the top medical adviser to the world’s airlines.”

The article references comments made by Dr David Powell, the medical adviser to the International Air Transport Association (IATA), which represents approximately 300 airline carriers worldwide. What Dr Powell’s actually said was since omicron is more transmissible people may be more likely to become infected during air travel.  He did not say they are. That was Bloomberg’s interpretation.

The IATA released a statement clarifying what was said by Dr Powell and not what was assumed to be true by Bloomberg.

There is a real paucity of data, true observational or epidemiological research data on viral transmission during air travel. Most of the literature on this is from early in the pandemic when mitigation measures were very limited. Lots of white literature articles mix the true data with messaging insinuations and interpretations like Bloomberg does. But Bloomberg’s intent was not to make air travel safer, that was made clear by the newsletter title, it was to push a domestic flight vaccine mandate agenda. Bloomberg is so obsessed with this agenda they have published 4 articles on it since Christmas, all calling for mandates on domestic flights.

What does the epidemiological research data on air travel and SARsCoV2 tell us? First, there is very little reliable data on omicron transmission and air travel. Its just too soon to know. Henceforth we are seeing a lot of postulating on it like extrapolating data reported on household spread of omicron (who wears a mask at home?) or on calculated transmission rates during non-flight conditions.  

The data that is available on transmission during flight is largely in documented cases of spread from way back in March 2020 before testing, masks, organized boarding procedures, and having a high degree of awareness about not flying if unwell. The task of linking infection to air travel is pretty arduous.

This was one area that I worked in while working with the DPH on COVID19 outbreaks. There are so many travel variables that feed into a person contracting the virus during an air travel event: the fitness of the individual, their immunity status, the transmission rate at the two ends of the travel, airline terminal filtration, type of mask worn, social distancing throughout the process, boarding practices and finally the flight its self. Specific to the flight where did the traveler sit, length of flight, type of mask worn etc.

Linking cases usually required genomic sequencing, which affords the ability to determine the homology (sameness) of the viral genome between people who test positive. This can help identify a single point source. But genomic sequencing was and is not done on a regular basis by the CDC Division of Global Migration and Quarantine (DGMQ) who we reported potential flight cases to.

A review article on international air travel, which tends to have longer duration flights, showed 15 of the 20 reported papers on transmission were before masking and other mitigation measures. Once mask wearing was put in place the average attack rates (the number of people who became ill divided by the number of people at risk or on the flight) dropped from 2-6.5 to 0-1.1. Another review study found similar findings.

So as much as I loathe the mask in flight, there is some evidence that it does seem to work while in the tin can. Does this data translate to omicron? We do not know. We need omicron specific data, not speculation. Cruise ship outbreaks of omicron among all vaccinated passengers and crew give us insight into how a fully vaccinated flight might behave. With the inability of vaccines to prevent transmission and infections, as evidenced by Carnival, Royal Caribbean and MSC breakthrough outbreaks its doubtful flights will be made safer by forcing all passengers to be vaccinates. 

Bloomberg’s agenda is clear as evidenced by the number of articles they have published calling for domestic flight vaccine mandates and who they quote or misquote.

Bloomberg’s go-to public health doctor is Dr Ashish Jha, who weighed in on domestic flight vaccine mandates: “It would make flying meaningfully safer and it would also motivate more people to get vaccinated. And if we want to get out of this pandemic, we need more people to get vaccinated. The pressure for doing things to put the pandemic behind us will grow more acute as we get out of this wave. There will be future waves. It’s not going to happen in three weeks, but once they [the Biden administration] realize omicron is not the end, I’m hoping that’s going to do it.”

Bloomberg, a business news agency, without data to support its claims, is calling for airlines to police domestic flight vaccination status and possibly, unnecessarily, negatively, impact their business in order to get more people vaccinated. To what end?