This week Spain reported what should have been cause for huge celebrations: according to the official coronavirus statistics, there were no new deaths in the 48 hours to midday on Tuesday.
Yet on the same day, at least two regions — Madrid and Castile-La Mancha — reported 17 deaths from the virus between them. The health ministry insisted it had not been informed of any death that had taken place in the previous 24 hours.
The confusion, in one of the countries worst hit by the pandemic, underlines what experts say is a big challenge as Spain relaxes its lockdown: a misleading impression that the coronavirus threat is past, which could encourage people to behave recklessly.
“The figures are driving us crazy,” said Jeffrey Lazarus, head of the Health Systems Research Group at the Barcelona Institute for Global Health.
“[The number] zero has a lot of power . . . It’s causing a false sense of security among the population.”
Speaking in parliament on Wednesday, Pedro Sánchez, Spain’s prime minister, hailed the zero deaths figure as “an achievement of everyone”. His government says it is a vindication of Spain’s harsh lockdown and its success in bringing down the daily death toll from a peak of 950 two months ago.
But some researchers say the government figures are deeply compromised because of revisions in ways the ministry of health counts the data.
“In real time, changes in detection or reporting can make it harder to work out the actual shape of the current epidemic,” said Adam Kucharski, an epidemiologist at the London School of Hygiene and Tropical Medicine.
The Spanish government has stopped explicitly listing how many deaths have been reported in the last 24 hours, switching to a contentious measure of how many people have died in the past seven days. Nor is it updating the overall tally of deaths as frequently or completely as before.
Breaking with its past practice, the ministry’s new policy adds new deaths to the running total only if they occur in the 24 hours before each daily bulletin. All other deaths are only added once a week, when the figures are revised.
After the changes were introduced in May, the death rates recorded by the health ministry plummeted. Its cumulative tally of deaths since the beginning of the outbreak also fell by almost 2,000.
“There is 100 per cent for sure a data problem,” said Mr Lazarus.
In the latest confusion, on Wednesday the ministry of health figures increased the tally of people who had died over the past seven days from 34 to 63. But at the same time the cumulative total they gave for all those who had died since the outbreak only went up by just one, to 27,128.
The problems with the figures are all the more serious since they come as the country is phasing out its lockdown measures.
“To come out and say there are zero deaths when deaths are taking place can create a lot of misunderstanding,” said Rafael Bengoa, a former Basque region minister for health and director at the World Health Organization.
“We are improvising at a moment when the population needs clear information.”
He said that Spain was bringing the pandemic under more control than other hard hit European countries and discounted any suggestion of political manipulation of the figures. Despite the problems with the Spanish data, the country’s death counts are an order of magnitude smaller than those in Italy and UK, which have averaged 85 and 247 a day respectively over the last seven days.
One problem is that the country’s regions — which run autonomous health systems under Spain’s decentralised government — have on several occasions provided late or inaccurate death numbers.
Lags are all the more important as the the government has pledged to focus on up-to-speed information. Late data falls outside the ministry of health’s criteria for the main coronavirus figures it produces, bringing totals down.
The Spanish government argues its focus on detecting infections as rapidly as possible — rather than concentrating on how many people are hospitalised or have died — fits the current stage of the epidemic.
“We are interested in the cases that are active now, that can infect people today, where symptoms have developed over the last one or two weeks,” said a senior Spanish health official.
Officials say that since the start of the outbreak, the typical notification time of new cases after the emergence of symptoms has come down from two-three weeks to 24-48 hours.The senior health official said there was now only a “very small number of cases” where information from the regions was arriving with a lag.
But Spanish data has been more volatile than that of any other rich country. Just a week ago, the country increased its overall tally of people dying from all causes during the pandemic to 43,000 — up by 12,000.
The overnight change — due to revisions rather than a sudden surge in deaths — briefly gave the country the world’s highest excess mortality rate, the measure most widely used to compare the pandemic’s toll across countries.
Asked at the weekend about the data revisions, Mr Sánchez, said the country could be proud of its “absolute transparency”.
But he acknowledged that, “until some months pass and the virus is definitively overcome . . . we are not going to know exactly what the number of deaths is”.