The United States yesterday lifted a 22-year ban on HIV-positive foreigners travelling to its shores, a restriction described by President Barack Obama as "rooted in fear rather than fact".
It has been clear for many years that the Aids virus is not spread easily by casual contact – the original rationale for the travel ban, introduced in 1987.
"We talk about reducing the stigma of this disease, yet we've treated a visitor living with it as a threat," Mr Obama said last October when he announced his intention to revoke the ban.
It covered tourists as well as foreigners seeking to live in the US, although short-term visitors could apply for a waiver, a procedure so complicated and bureaucratic that many people concluded that it was not worth the effort involved.
The lifting of the ban now means that even asylum-seekers and people applying to become residents in the US no longer have to take a mandatory HIV test. For some families, it will mean the end of painful separations between family members living in the US and abroad.
Mr Obama said it would also now be possible to organise an international Aids conference on American soil in 2012 without fear of foreign participants being refused entry or detained for long periods at the airport, which had occurred before an Aids conference in 1989.
The travel ban stemmed from a speech given in May 1987 by President Ronald Reagan where he announced a system of routine HIV testing to find out the extent to which the virus had penetrated US society. It was widely condemned by Aids scientists around the world as unjust and unnecessary.
A few other countries, including Libya and Saudi Arabia, have also enacted bans on HIV-positive travellers. Some, such as Australia, justify the ban on the grounds that HIV-positive immigrants are likely to be a burden on the health system.
"Removing the ban is long overdue and we congratulate the US government on seeing economic and medical sense," said Lisa Power, head of policy at the Terrence Higgins Trust. "We hope other countries with similar bans in place will now remove them too."