President’s order takes effect Friday and halts most travel from Europe * Coronavirus – latest newsDonald Trump has announced that the US is temporarily suspending most travel from Europe to the US in an effort to contain the spread of coronavirus.In a rare Oval Office address, the president said the US would bar arrivals from 26 European countries for 30 days from midnight on Friday, accusing them of not acting quickly enough to address what he called the “foreign virus”.Details of how exactly the restrictions will work have yet to be fully clarified, and public health experts have questioned the effectiveness of the measure when the virus is already being transmitted person-to-person in the US.Here is what we know: Which countries does the ban apply to?According to the US Department for Homeland Security (DHS) and the president’s proclamation, the ban applies to the countries belonging to the 26-member Schengen passport-free zone. These are:Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, and Switzerland.As non-members of Schengen, Britain and Ireland are not covered by the ban. Who is affected?The restrictions will cover “most foreign nationals” who have been in any of the Schengen zone countries “at any point during the 14 days prior to their scheduled arrival to the US”, the DHS says.The ban does not apply to US citizens returning home, nor to foreign nationals who are legal permanent residents of the the US. Also exempted are foreign nationals who are: * married to US citizens or legal permanent residents * parents and guardians of US citizens or legal permanent residents aged under 21 * brothers and sisters of US citizens or legal permanent residents, providing both are unmarried and under 21 * children or foster children of US citizens or legal permanent residentsIt also does not apply to ship and plane crews; foreign nationals invited to the US to help tackle the virus; foreign government officials and their immediate family; and foreign nationals who work for the US armed forces, international organisations including Nato and the UN, or whose entry “is deemed in the national interest”.The ban resembles the restrictions imposed by the US on foreign nationals who have visited China in the 14 days before their arrival to the US. Washington has also issued restrictions on travellers from Iran, and “do not travel” warnings to areas in Italy and South Korea. When does the suspension start and how long will it last?The restrictions will begin at 11.59pm ET on Friday and are scheduled to last for 30 days, but could be adjusted subject to conditions on the ground. How will it work in practice?There is little clarity on how the restrictions will be implemented beyond the statement that US authorities will take the necessary steps as regards visas and at point of entry to the US, while also ensuring that “any alien subject to this proclamation does not board an aircraft travelling to the United States”.The DHS has said it will issue practical guidance within 48 hours. What about British citizens travelling from outside the UK, and Europeans travelling to the US from Britain?It seems clear from the proclamation that as foreign nationals, Britons travelling to the US from within the Schengen zone – or who have spent any of the previous 14 days there – will be covered by the suspension, although it is not yet clear how that will work in practice.Nationals of the Schengen member states should be able to fly to the US from Britain but will have to have spent 14 days in the UK first. Again, how exactly this will be checked is not yet clear. Will the measure be effective?A study published in the Science journal found the effectiveness of travel restrictions in China was limited once the disease had spread widely within the country.On 23 January, Chinese officials banned travel in and out of Wuhan, where the Covid-19 outbreak originated, but by then the virus had spread to other cities and the travel ban only delayed its progression by three to five days, it suggested.Daniel Drezner, a professor of International politics at Tufts University’s Fletcher School, questioned whether limiting travel from Europe would amount to anything more than “a drop in the bucket”, given the number of people who have already been infected with the virus in the US.According to the latest US figures, more than 1,250 people in 44 states and Washington DC, have tested positive for coronavirus and at least 30 have died.Democrats were also swift to criticie Trump’s approach, saying the president had failed to address the shortage of testing kits that has hampered containment efforts across the country.“The best way to help keep the American people safe and ensure their economic security is for the president to focus on fighting the spread of the coronavirus itself,” the Democratic leaders of the Senate and House said in a joint statement.