Was Emirates to blame for 100 passengers feeling ill on a recent flight?

By A.W. | WASHINGTON, DC

THE initial reports were alarming: 100 passengers on an Emirates Airlines flight from Dubai to New York had taken ill, and the plane was in quarantine at New York’s JFK Airport. That was probably an exaggeration. A spokesman for New York’s mayor later reported that 19 people were ill; ten of them were taken to a nearby hospital, and the other nine refused treatment. (Other reports said 11 were taken to the hospital.) The sick passengers appeared to have flu-like symptoms.

Planes are widely regarded as flying disease-incubators. If one passenger is sick with a contagious disease and coughing those germs into the air, it makes sense for fellow-flyers to feel that the germs will simply be inhaled by everyone else on the flight, since there is nowhere else for the things to go.

In reality, though, the situation is not that bad. Allen Parmet, a former US Air Force flight surgeon who serves as an aerospace medicine consultant, explained recently to The Verge, a technology and science news site, that infections actually don’t spread well on planes. The reason is the very dry air in the cabin. Many bacteria die in the low humidity. As for viruses, they travel on water droplets when a person coughs or sneezes. But these water droplets also evaporate in the low humidity, and the plane’s fast airflow from ceiling to floor prevents them from travelling far.

The downside is that people do cough more on planes, due to the same low humidity. People are also likely to sneeze more, due to the presence of allergens. Cat allergy problems are particularly common, said Mr Parmet, since cat owners have dander all over their clothes, and neighbors who are allergic to the dander end up sneezing.

But it is unlikely that a particularly scary disease like Ebola will spread on a plane. Precautions around this are high in countries with serious epidemics. In much of southern Africa, due to the Ebola outbreak in Congo, all outbound passengers walk through thermal scanners to determine whether they have a fever. Elsewhere, visibly sick passengers are sometimes denied boarding.

The greater danger is when a plane lands, because the airflow stops, the humidity may rise, and diseases can begin to spread more effectively. This is when public health officials must make quick decisions about whether and how to isolate sick passengers or those who were sitting near them. But in the absence of a major outbreak like Ebola, it can be hard to compel passengers to be screened or quarantined, although at this point the risk can be more about introducing new diseases in the arrival country than about fellow-passengers getting sick.

On the Emirates flight, all 549 passengers underwent a medical screening before entering the Airport, according to the Centres for Disease Control. An epidemiologist told Popular Science that the procedure was not really a true quarantine, which would require isolating everyone involved from the general population, but rather a temporary detention for a few hours to allow for testing and treatment.

Given the long distance from Dubai to New York, it might seem possible for disease to spread and incubate on board. But most viruses take days to show symptoms, and there were indications that the illness was contracted by people before they boarded the plane. This tale will probably end the usual way. A few passengers, by the laws of probability, will get sick in the coming week, and they will assume it had something to do with all the germs floating around the plane. It may not be true, but it is for them a satisfying enough explanation.