Every day, the statistics bring more grim headlines: “Italian death toll passes 20,000”, “Record UK daily death toll”, “Europe’s fatalities pass 100,000”. Across the world, people await national updates on the coronavirus – and compare their country with others.

The comparison game has been especially marked in Belgium, which on paper has the unhappy title of highest number of Covid-19 deaths per capita in Europe. Belgium – population 11.5 million – has counted at least 6,675 deaths since the start of the outbreak, more than Germany, which is nearly eight times more populous.

But such comparisons can be misleading. Unlike the UK, Italy or Spain, Belgium counts all coronavirus deaths outside hospitals in its daily statistics: deaths in care homes account for 53% of the total. Belgium’s official toll also includes people suspected of having died of coronavirus, without a confirmed diagnosis. Nearly all deaths in care homes (94%) are suspected Covid-19 cases, rather than confirmed – an approach that has led some to complain Belgium is overestimating the number of fatalities.

Marc Van Ranst, a Belgian virologist, told the Flemish national broadcaster that the official methodology was “dumb”, while some ministers have voiced concern in private. “Nobody would benefit from reporting people as Covid deaths if they are ordinary deaths from old age,” a federal government source told Flemish daily De Tijd last week.

Belgian officials have defended the approach, arguing it is more precise and saves lives, as information has prompted policy changes, such as mass testing in care homes. “More and more countries are beginning to copy the Belgian model,” Prof Emmanuel André, the federal government’s Covid-19 crisis spokesman, told journalists this week.

The Netherlands has recorded at least 4,050 deaths from coronavirus, 24 deaths per 100,000 people, compared with 55 per 100,000 in neighbouring Belgium. But a Dutch health ministry spokesman said the Netherlands figure was “an underestimation” because it only included deaths where coronavirus had been confirmed. Between 6 and 12 April, 5,036 people died in the Netherlands, compared with an average of 2,857 in the same week in the three previous years, a number of excess deaths that helps give an idea of the scale of undercounting.

The UK has reported that at least 18,738 people have died in hospitals after testing positive for coronavirus. This headline figure, which is given in the government’s daily briefing, also does not tell the full story. Figures from the Office for National Statistics show Covid-19 fatalities in care homes in England and Wales more than quadrupled in a week, rising to 1,043, while coronavirus deaths at home more than tripled in the same period to 466.

In France, the care home number is 7,896, which represents 40% of the country’s overall coronavirus deaths. The figure is almost certainly higher. France’s health authority has been giving care home death figures since 3 April, when they were only “partial”. Now they are said to be more or less complete figures.

France has more than 10,600 public and private care homes and they are a long ignored part of the health system. Covid-19 has revealed a lack of equipment and material, including masks and testing. But it has also shown the overwhelming dedication of carers, who are largely underpaid, and under recognised for their work.

One of the worst cases is in Mougins, near Grasse on the French Riviera, where 37 of 109 residents of a private care home have died of Covid-19, and 14 of 50 staff tested positive when testing was finally done.

In Spain, the official number of coronavirus deaths is about 20,000. But it could be much higher if deaths in care homes are taken into account, according to the regional governments of Madrid and Catalonia, the areas hardest hit by the pandemic. Collating data from care homes and funeral directors, they say that in the two regions respectively about 4,275 and 3,000 care home residents have died from the virus.

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The Spanish health ministry did not request care home data until 8 April and several of the country’s 17 autonomous regions have yet to provide it. Last Friday the ministry said it would continue to base its statistics on deaths of people who had been tested for the virus, thus excluding until now most care home deaths.

In most of central Europe, coronavirus numbers are still much lower than in countries further west, but there is concern here too that care homes are vulnerable and could quickly lead to rising numbers. Hungary’s far-right government and the liberal mayor of Budapest have been locked in a blame game over one care home in the city which has recorded 223 residents and 19 workers as being infected, about 10% of the country’s total coronavirus cases.

Neighbouring Slovakia has some of the lowest numbers in Europe, and until last week, just two people had died from the virus. However, seven people have since died after an outbreak in a nursing home in the town of Pezinok, and the government has promised to embark on widespread testing in homes across the country.

Variations in counting of Covid-19 deaths, different testing strategies and lockdown policies make international comparisons a minefield. “A comparison between [EU] member states is difficult and should be done with extreme caution,” said a spokesperson at the European Centre for Disease Prevention and Control, the EU agency to tackle infectious diseases.

The agency is urging governments to count everyone who dies of coronavirus, irrespective of whether they die in hospital, a care home or private residence, as well as recording deaths where Covid-19 was “the main or contributing cause”.

Data for France, Spain and central Europe was collected on 21 April; data for the Netherlands, the UK and ECDC statistics on 23 April, and for Belgium on 24 April.

• This article was amended on 27 April 2020. The data was collected on various dates in April, as above, not during March as a previous version said. This has been corrected.