A couple of flights from Europe landed at the Philadelphia International Airport on Thursday and their passengers were sent for medical check-ups. A day earlier, a plane from Dubai, United Arab Emirates, was briefly quarantined at the Kennedy International Airport in New York after initial reports of up to 100 sick travelers on board.
It sounds scary. Flat loads of passengers who report flu-like symptoms naturally raise concern about a broader outbreak of the disease. But quarantine reports and medical checks are actually evidence of a complex health system that works exactly as expected, the Centers for Disease Control and Prevention said. And there is a good explanation of why everything seemed to happen at once.
Basically, there's no reason to worry. However, it might be useful to know more about what happened.
Flight of the Emirates 203 airline
The flight from Dubai landed on Wednesday morning at Kennedy airport and was quarantined. The pilot had alerted officers on the ground after dozens of passengers reported that they felt sick, a police officer told The New York Times on Wednesday.
Initially, the CDC said that it was thought that around 100 of the passengers were sick, but after all were evaluated, only 19 of the more than 500 travelers were considered sick. Of these, 11 were taken to the hospital. They had the flu or a common cold, said the CDC.
American Airlines 755 and 1317 flights
Flight 755 arrived at the Philadelphia International Airport from Paris and Flight 1317 flew from Munich. Twelve passengers had flu symptoms on flights. The 250 passengers and crew were retained for medical review after leaving the flight. In addition to the 12 sick passengers, they were all allowed to leave.
"Nobody was very sick, they were all allowed to continue on their way," said Dr. Marty Cetron, director of the division of migration and global quarantine at the CDC.
Why were they all sick at the same time?
Many of the passengers had been on Hajj, an annual pilgrimage that millions of Muslims make to Mecca, Saudi Arabia, to follow in the footsteps of the Prophet Muhammad. This year, Hajj was at the end of August, and it is believed that at least 1.7 million people attended. Having traveled from all over the world, they were close for several days.
The spread of the disease is to be expected. So is the fact that those who live in the United States took various routes home (hence the reported illnesses on flights from the Middle East and Europe).
"Everywhere millions of people congregate, the transmission of the disease increases," T.J. Doyle, medical director of Stat MedEvac, which provides advice in cases of emergency like this.
It has happened before, but "the Saudi government is very careful in detection and treatment," Cetron told the CDC.
Is it serious?
No more serious than the regular outbreaks of flu that appear in autumn and winter each year.
The plane quarantine at Kennedy airport was highly analyzed, but the response system worked exactly as expected, Cetron said.
The center was called 30 minutes before the flight landed. The agency was then able to verify the global databases on how diseases were spreading worldwide. Local health services and laboratories were alerted to prepare for their arrival. The plane was stopped far from the terminal and people were checked and treated.
Is this a more common occurrence?
Agencies like the CDC are aware that people travel internationally. This type of occurrence is relatively rare, occurring less than once a year, said the CDC.
The agency spends much more time looking at people's travel records to find out where they were exposed because it may take some time for symptoms to be reported.
"The vast majority of our responses are reconstructing history and finding all people in the US and other countries, finding those at greatest risk, telling them how they can be tested and treated," Cetron said.
Is there more risk of illness on flights?
It can vary according to how infectious a disease is and whether it can be spread through the air or water droplets.
But the possibility of contracting a disease on an airplane increases with the amount of time spent in the air, "as if you were on a Greyhound bus for 10 hours," Doyle said. "There is nothing inherently risky about being on a plane."
Of course, traveling is always a bit disgusting. A recent study of frequently touched surfaces at the Helsinki airport in Finland collected traces of rhinovirus, the source of the common cold and the influenza A virus. They found traces in half of the luggage trays, more than in any of the other surfaces that they tested. None of these viruses were found on the surfaces of the toilets at the airport, they said.
The airline staff and Customs and Border Protection officers are trained to detect and inform sick travelers. If people are reported to be sick, the CDC will vary their response based on how infectious the disease is.
What happens when people are in Hajj?
The CDC recommends that those who go get vaccinated and make sure their families are protected because vaccination does not prevent people from carrying pathogens.
And this is as important for a common illness as the flu, as it is for any other disease. "Influenza kills thousands of people every year," said Doyle of Stat MedEvac. "More people die of flu that die of Ebola".