The growth of new coronavirus infections in Spain has fallen to a record low since the outbreak began, as Europe’s worst-hit country by confirmed cases braced for the reopening of some sectors of its economy this week.

Deaths increased by 619 in the past 24 hours and were likely to exceed 17,000 on Sunday, but Spanish health ministry figures showed new cases had grown by 2.6% over the same period – the lowest rate since the pandemic took off in the country a month ago and caseloads started increasing by one-fifth every day.

Evidence that a strict lockdown, in place since 14 March, was working came as some factory and construction workers prepared to return to work on Monday, a call that has drawn criticism in some quarters.

Quick guide What are coronavirus symptoms and should I go to a doctor? Show Hide What is Covid-19? Covid-19 is caused by a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals. The World Health Organization (WHO) has declared it a pandemic. What are the symptoms this coronavirus causes? According to the WHO, the most common symptoms of Covid-19 are fever, tiredness and a dry cough. Some patients may also have a runny nose, sore throat, nasal congestion and aches and pains or diarrhoea. Some people report losing their sense of taste and/or smell. About 80% of people who get Covid-19 experience a mild case – about as serious as a regular cold – and recover without needing any special treatment. About one in six people, the WHO says, become seriously ill. The elderly and people with underlying medical problems like high blood pressure, heart problems or diabetes, or chronic respiratory conditions, are at a greater risk of serious illness from Covid-19. In the UK, the National health Service (NHS) has identified the specific symptoms to look for as experiencing either: a high temperature - you feel hot to touch on your chest or back

a new continuous cough - this means you’ve started coughing repeatedly As this is viral pneumonia, antibiotics are of no use. The antiviral drugs we have against flu will not work, and there is currently no vaccine. Recovery depends on the strength of the immune system. Should I go to the doctor if I have a cough? Medical advice varies around the world - with many countries imposing travel bans and lockdowns to try and prevent the spread of the virus. In many place people are being told to stay at home rather than visit a doctor of hospital in person. Check with your local authorities. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

In a letter to the prime minister, Pedro Sánchez, Catalonia’s regional president asked to see the medical and epidemiological advice on which the decision was taken. Quim Torra also suggested that the move would provoke “a rise in infections and a situation of collapse for Catalonia’s health system”.

Speaking after a videoconference with the leaders of Spain’s autonomous regions on Sunday afternoon, Sánchez said the country remained firmly in lockdown despite the easing of restrictions on non-essential workers. Those returning to work were being advised to maintain social distancing and face masks will be handed out in metro and rail stations.

“I want to be very clear,” he said. “We are not entering a phase of de-escalation. The state of emergency is still in force and so is the lockdown. The only thing that has come to an end is the two-week extreme economic hibernation period.”

The prime minister said anyone who was ill or pregnant, or showing even the mildest symptoms, should stay at home. “General confinement will remain the rule for the next two weeks and the only people allowed out will be those going to authorised jobs or making authorised purchases,” he said.

Sánchez said there could be a “progressive and very cautious” relaxation of the lockdown “in two weeks’ time at the earliest” – but only if current trends continued.

The World Health Organization has said there could be a “deadly resurgence” of the coronavirus if countermeasures are lifted too soon, while one of the Spanish government’s own experts has said he thought it would have been sensible to keep non-essential workers at home for longer.

Sánchez has warned the lockdown is likely to be extended beyond 26 April. Under the rules of confinement, people are allowed to leave their homes only to got to work or to buy food or medicine. He also called for unity in the face of what he termed an unprecedented “total war” and urged a de-escalation of political tensions. “We are dealing with a completely new situation … I do not have – nor will I have – any enemy but this virus.”

Optimism over Spain’s slowing infection rates was tempered by continuing speculation the actual number of Covid-19 deaths in the country may be much higher than official figures.

Recently released data from judicial authorities in Madrid, for example, suggests that 6,600 more people than usual died in the last two weeks of March, compared with the official tally of 3,500 Covid-19 deaths in the region.

Infection rates continued to decelerate elsewhere in Europe including the Netherlands, where coronavirus cases topped 25,000 on Sunday with more than 2,700 deaths.

Italy recorded its lowest daily rise in deaths in three weeks on Sunday, with 431 people killed by the virus and new cases growing by 1,984, or 2%.

The curve for infections has been flattening over the past week or so, and Walter Ricciardi, the scientific adviser to the Italian government on the coronavirus outbreak, told the Guardian last week that the plateau could continue for 20-25 days before there is a definitive decrease.

To date, there have been 156,363 cases of coronavirus in Italy, including 19,899 victims and 34,211 survivors

The European commission chief, Ursula von der Leyen, told the German daily Bild that elderly people on the continent may need to remain isolated until at least the end of the year to protect them from the virus, even if freedom of movement is relaxed for others.

“Without a vaccine, we have to limit as much as possible contact with the elderly,” she said. “I know it’s difficult and that isolation is a burden, but it is a question of life or death, we have to remain disciplined and patient.

“Children and young people will enjoy more freedom of movement earlier than elderly people and those with pre-existing medical conditions,” she said.

In an Easter Sunday mass performed to a handful of people in St Peter’s Basilica and livestreamed around the world, Pope Francis said he hoped rivalries from before the second world war “do not regain force” as a result of the pandemic. He said the crisis presented the European Union with an “epochal challenge, on which will depend not only its future but that of the whole world”.

Nearly 110,000 people have died from coronavirus, according to the Johns Hopkins University tracker, with more than 1.78 million people diagnosed.

Tight restrictions on movement came into force on Sunday in Jerusalem, where predominantly ultra-orthodox Jewish areas have been hit disproportionately by the virus, in part because influential rabbis were slow to shut synagogues and religious seminaries.

Mainland China reported 99 new cases on Saturday, of which all but two were imported, and the country’s national health commission said there were no new deaths.

The two local cases were in Heilongjiang, China’s northern-most province, which borders Russia. Of the 97 imported cases recorded, 43 were in the city of Shanghai. There were no new cases reported in Hubei, the province where the outbreak is believed to have begun and was officially announced 103 days ago.