The flight left New York last Friday and stopped off in Sweden before continuing on to Asia and included around 50 Swedish passengers, according to the Dagens Nyheter (DN) newspaper.
Authorities from the World Health Organization (WHO) contacted Sweden's Institutes for Infectious Disease Control (Smittskyddsinstitutet – SMI) after confirming another passenger onboard had been infected by the A/H1N1 flu virus and was suffering from severe symptoms.
“We want to inform those who were onboard that they should contact health providers if they display any symptoms,” said Anders Tegnell, head of SMI's infectious disease control unit, to DN.
The alert comes as SMI decided to lift its warning against traveling to Mexico.
According to information from several independent sources, the risk of becoming seriously ill from infection with the swine flu virus in Mexico is now greatly diminished, said a statement from SMI posted on the agency's website.
In addition, the government decided to give the go ahead to Sweden's National Board of Health and Welfare (Socialstyrelsen) to sign a letter of intent agreement with vaccine manufacturer Glaxo Smith Kline (GSK) for the delivery of nine million doses of pre-pandemic vaccine against the A/H1N1 flu virus, as well as 200,000 packages of the antiviral medication Relenza.