Nearly one million extra deaths relating to the Covid-19 pandemic occurred in 29 high-income countries in 2020, found a study led by a team of Oxford University researchers.

Experts said although there are no equivalent statistics, Bangladesh also had more deaths than expected last year. This needs to be addressed through better healthcare to prevent avoidable deaths, they said.

Published in the British Medical Journal on May 19, the study found that except for Norway, Denmark and New Zealand, all other countries examined had more deaths than expected in 2020, more so among men than women.

The five countries with the highest absolute number of excess deaths were the US, UK, Italy, Spain, and Poland.

Measuring excess deaths -- the number of deaths above that expected during a given time period -- is a way of assessing the impact of the pandemic on deaths in various countries, said the researchers.

A team of international researchers, led by Bangladeshi physician-epidemiologist Dr Nazrul Islam from the Nuffield Department of Population Health at Oxford, set out to estimate the direct and indirect effects of the Covid-19 pandemic on mortality in 2020 in 29 high-income countries.

"The extra deaths indicate that the Covid-19 pandemic has claimed many lives, both directly and indirectly. Even though not directly supported by our study, the situation in Bangladesh may not be very different from what we have observed in these developed nations," Dr Nazrul Islam told The Daily Star yesterday.

"Covid-19 deaths have been shown to be under-reported in most countries around the world. Moreover, deaths due to other causes such as cancers may have been higher than previous years," he said.

"Therefore," he added, "the actual number of excess deaths due to the Covid-19 pandemic may be higher than the reported deaths."

Using a mathematical model, the research team calculated weekly excess deaths in 2020 for each of the 29 countries, accounting for age and sex differences between countries, and also for seasonal and yearly trends in mortality over the four preceding years.

Overall, an estimated 979,000 total excess deaths occurred last year in the 29 countries analysed. All countries experienced excess deaths, except New Zealand, Norway, and Denmark.

The five countries with the highest absolute number of excess deaths were the US (458,000), the UK (94,400), Italy (89,100), Spain (84,100), and Poland (60,100). Only New Zealand had lower overall deaths than expected (2,500 less).

The excess deaths were largely concentrated among people aged 75 or older, followed by people aged 65-74 years, while deaths in children under 15 were similar to expected levels in most countries and lower than expected in some countries.

In most countries, the estimated number of excess deaths exceeded the number of reported deaths from Covid-19. For instance, in both the US and the UK, estimated excess deaths were more than 30 percent higher than the number of reported Covid-19 deaths.

"It is unknown if everyone who died in Bangladesh in 2020 was tested to accurately determine whether the cause of death was Covid-19. So, the actual number of excess deaths due to Covid-19 may be higher than the reported deaths," Dr Nazrul said.

"Moreover, the number of deaths due to causes other than Covid-19 is also not precisely known in Bangladesh, which makes it difficult to estimate the extent of excess deaths in the country."

Dr Mushtuq Hussain, consultant of the Institute of Epidemiology, Disease Control and Research (IEDCR) in Bangladesh, also thinks there were excess deaths in the country last year.

"There is a need for similar death analysis in the country. It will help to formulate policy in the healthcare system during the pandemic," he told The Daily Star yesterday.

"Actually, we need to focus on a community-based healthcare system to prevent avoidable deaths."

In most countries, age-specific excess death rates were higher among men than women, and the absolute difference in rates between the sexes tended to increase with age. However, in the US the excess death rate was higher among women than men in those aged 85 years or older, according to the study.

"Reliable and timely monitoring of excess deaths will help to inform public health policy in investigating the sources of excess mortality in populations and help to detect important social inequalities in the impact of the pandemic to inform more targeted interventions," Dr Nazrul said.

Future work will also be needed to understand the impact of national coronavirus vaccination programmes on mortality in 2021, the researchers concluded.