People with symptoms of coronavirus may be asked to isolate for an extra three days, after government scientists raised concern about a steady rise in the number of cases in the UK, with parts of Europe seeing significant spikes. The Guardian understands that the government is looking at increasing the isolation period for those who have symptoms from seven to ten days in line with the developing science on the virus’s incubation period and how long it remains contagious. The current advice is that those with a new continuous cough, a fever or loss of sense of smell or taste must stay at home for seven days and members of their household must do so for 14 days. On Wednesday, the government’s official dashboard showed 83 Covid-19 associated deaths and 763 newly lab-confirmed infections, and there appears to have been a slight rise in infections as lockdown restrictions have eased. Niall Dickson, chief executive of the NHS Confederation, which represents NHS leaders, told MPs that NHS managers were very worried about a second wave. He said: “I would say in relation to the second spike issue or something coming, the levels of concern among our members – the people who are leading NHS trusts, who are leading in primary care and all levels in the systems – is very high. “I mean, of course, there’s real concern about winter and the compounding factors there, but also about an earlier spike. We have already mentioned exhausted staff [and] we are already trying to rebuild other services.” Ministers are also likely to decide on tighter restrictions for travellers returning from a number of new European countries that are experiencing a surge in cases over the coming days, including Belgium and Luxembourg. At least 30 Conservative MPs are to increase pressure on the government to reconsider its approach to the 14-day quarantine for travellers from at-risk countries, amid warnings that more European countries with Covid-19 spikes could have restrictions reimposed. The Guardian understands that concerned MPs are coordinating an approach to the prime minister this week in order to urge him to cut the two-week time-frame for quarantine with the use of mass testing. Henry Smith, the MP for Crawley, which includes Gatwick airport, said tests could help cut the quarantine period to seven days, coupled with a more regional approach based on where cases of the virus are rising. “Cutting down a week makes a big difference – that could be a way to satisfy the paramount public health concerns and still allow travel to continue to a large degree,” he said. Oliver Dowden, the culture secretary, said on Wednesday that ministers believed there was “no viable” alternative to the quarantine period. “It’s not a silver bullet … You can test negative initially and then the virus can incubate and you can spread,” he told LBC. However, senior Conservative and Labour MPs, as well as the chief executive of Heathrow, John Holland-Kaye, pointed to airport testing systems used in other nations that could play a part in shortening the isolation time for returning travellers. Quarantine restrictions on travellers returning to England from Belgium and Luxembourg may be reimposed in the next two days, as ministers grapple to ward off any fresh threat of a potential second wave of coronavirus in some countries. Ministers are also understood to be closely monitoring rises in the number of infections in Croatia. The former cabinet minister David Davis said airport testing could be a partial substitute for quarantine periods. “Vienna has been doing this for months. I don’t understand why we haven’t,” he wrote on Twitter. “Nothing is perfect – you are as likely to catch the virus on the London underground back home as you are on the plane or on holiday.” Theresa Villiers, a former aviation minister, said MPs were urging the Department for Transport to find a better solution than the two-week quarantine period, even though testing alone was unlikely to be the answer. “I know colleagues are urging DfT to get this done, but I fear it may not be in time to save this summer’s holidays,” she said. “I hope that testing might be deployed to reduce quarantine periods, but I’m not sure testing is a complete substitute. The big problem is that getting either approach in place for regionalised quarantine and a new airport testing regime to reduce the quarantine period will take time.” Scientists have cautioned that mass testing at airports is unlikely to prevent the need for quarantine measures as the incubation period for the virus could be up to five days before a test can detect if someone is positive. Modelling by the London School of Hygiene and Tropical Medicine found that testing on arrival may only catch around 50% of cases – but combined with a seven-day quarantine with a test on the final day, that rate could reach 94% and cut the quarantine period by a week. Dowden said people “should continue to book holidays, but just bear in mind that [fresh quarantines] may happen, and sadly it has happened in Spain”. He said he understood people’s anxiety and frustration. “Believe me, from friends and family and people I meet on the street, everyone is asking this question [about which countries might be next],” he said. The Covid-19 rate has almost tripled in Belgium this month, from 5.3 to 15.1 per 100,000 of the population, with the number of cases up from 615 to 1,751, leading to new limits on the numbers of people allowed to socialise. Luxembourg’s rate of infection is 15 times higher per capita than in the UK. Croatia’s tourist board issued a statement on Wednesday saying the country was still “extremely safe” for tourists and that increased numbers of cases had been largely in the far eastern regions, away from the popular coastal areas populated by tourists.