The US was worst hit by the pandemic in the G7 big Western democracies over the first year of Covid-19, according to an updated study of excess death figures.

The analysis, done for the BBC by the Health Foundation, comes on the eve of the G7 summit in Cornwall.

It measures deaths above expected levels for a normal year.

Last year, an earlier BBC study showed that at that point, the UK had been hardest hit. Overall, UK outcomes are now second worst in the G7.

The analysis shows that in the second half of last year in particular, US levels of excess deaths failed to drop back as much as other comparable industrialised nations.

However, the UK’s worse outcomes in the first wave, and a significant peak of deaths in December and January, still mean that overall UK outcomes were second worst, on one measure just behind the US.

The other G7 countries – Italy, France, Canada, Germany and Japan – had fewer excess deaths, with the latter three significantly fewer.

The principal measure of comparison is excess deaths. This is the percentage of above normal deaths over the year, which can help account for different measurement techniques in different countries.

It is a measure of the overall impact of the pandemic, including directly from the disease and from the response to it.

The raw numbers of reported Covid-19 deaths show the UK as the worst in the G7, but most analysts believe there has been structural under-reporting of Covid deaths in the US, which has seen far less testing, making the excess deaths comparison more appropriate.

The analysis shows that between March 2020 and February 2021, there were a fifth more deaths than in a normal year for the US (+20.2%) and a little bit under a fifth for the UK (+19.6%),

Italy was lower, but still significantly hit (+17%), French excess deaths were one-10th higher (+10.2%), and then Canada (+5.1%) and Germany (+4.9%) saw deaths only one-20th up on normal.

Japan’s deaths (-1.4%) were actually lower over this first year than would have been expected.

Another measure, adjusted for the size of population, showed that there were 227 excess deaths for every 100,000 people in the US.

There were just under that both for the UK (181) and Italy (180). France was clearly lower at 125. Canada (92) and Germany (92) had an excess death rate below one in 1,000. And Japan’s figure was lower still (47).

Comparing the pandemic waves over the course of the year shows that the level of excess deaths in the US remained high between peaks and never fell back to zero. This reflects an absence of lockdowns and different policies across different US states.

Charles Tallack from the Health Foundation said: “Understanding how similar countries have fared over the pandemic is a vital part of learning lessons for the future.

“Excess deaths – how many more deaths there have been than in a usual year – is generally regarded as an objective and fair way of comparing countries.

“Over the first year of the pandemic, the US comes out as the worst affected country in the G7 with deaths of up to 25% more than usual.

“The UK is not far behind in second place. Japan has fared best followed by Germany. These rankings remain the same even when we use slightly different approaches, so we’re confident that they provide a fair comparison of the first year.”

Other metrics showed that the US has had the fastest economic bounce-back, already having made up the lost growth in the pandemic. The US economy is forecast to grow 6.9% this year, after a fall of 3.5% last year.

The UK is expected to grow a similar amount at 7.2% this year, but that is after the largest fall in the G7 in 2020 of -9.8%. Canada is also bouncing back fast, with growth forecast this year of more than 6%, after a relatively modest hit last year of 5%.

There have also been marked differences within the G7 on the rollout of vaccinations.

The share of the population that is fully vaccinated almost exactly follows the countries most hit by the pandemic. The US has vaccinated the most, alongside the UK, followed by Italy.

Japan has vaccinated the least, then Canada, with France and Germany in the middle.