The World Health Organization (WHO) said on Thursday that almost 15 million deaths globally were directly or indirectly associated with the COVID-19 pandemic by the end of 2021.

The full COVID-19 death toll, or "excess mortality," was approximately 14.9 million between January 1, 2020, and December 31, 2021, the WHO said.

It indicates that the mortality burden caused by COVID-19, directly or indirectly, greatly exceeds the number of confirmed COVID-19 deaths, which is about 6.26 million as of May 7, 2022.

Excess mortality in countries

This figure is calculated as the difference between the number of deaths that have occurred and the number that would be expected in the absence of the pandemic based on data from earlier years.

The excess mortality includes deaths related to COVID-19 and the ones related to the pandemic's impact on health systems and society, according to the WHO.

Health systems overwhelmed by the pandemic were at times unable to accommodate people seeking treatment for other ailments.

According to the WHO, most of the excess deaths – 84 percent – were concentrated in Southeast Asia, Europe and the Americas, and some 68 percent in just 10 countries globally.

Meanwhile, middle-income countries accounted for 81 percent of the 14.9 million excess deaths, while high- and low-income countries accounted for 15 and 4 percent, respectively.

The global death toll was higher for men, with 57 percent, than for women, 43 percent, and higher among older adults.

'Dynamic zero-COVID' policy to protect elderly

China has been sticking to its "dynamic zero-COVID" policy since extinguishing the COVID-19 outbreak in Wuhan in 2020, as the number of new infections nationwide has stayed at an extremely low level.

Meanwhile, China has encouraged the public to receive vaccines to boost nationwide immunity in the face of new waves of COVID-19 variants. These efforts have paid off. 

China has administered about 3.4 billion COVID-19 vaccine shots, with about 89 percent of the population being fully vaccinated, according to the National Health Commission (NHC).

Thanks to the high vaccination rate and dynamic zero-COVID policy, China was already on the right track to protect people's lives when the Omicron variant went rampant globally.

Some have argued that China's stringent approach comes at too high of a cost. Zhong Nanshan, China's top epidemiologist, said the cost is indeed quite high, but "if you ignore the virus and just let go of the situation, the cost will be even higher."

Although China's overall vaccination rate is high, vaccination among the elderly could be improved. Data from the NHC shows that 212 million elderly have been fully vaccinated, but more than 50 million have yet to complete a full course. That's roughly the population of a mid-sized country.

The country's healthcare system would be overwhelmed if such a large population were infected with COVID-19 and sought medical care all at once. 

"Under such circumstances, the country's medical resources will be stretched too thin should we adopt a laissez-faire epidemic containment approach," said Liang Wannian, a top Chinese epidemiologist, at a previous press briefing.

According to a new study based on an Omicron variant transmission model in the journal Nature, China risks a deluge of infections that could lead to about 1.55 million deaths if it abandons its dynamic zero-COVID policy. 

The elderly face significantly higher risks without vaccination than the younger population. During the recent Omicron surge in Hong Kong, over 6,000 infected individuals have died with the medium age of 86, 90 percent of whom were unvaccinated.

In Shanghai's recent surge, most of the COVID-19 deaths were individuals over age 80 who were unvaccinated and had underlying diseases.

Resilient health systems in demand

The WHO called for all countries to strengthen their health services during crises, as well as their health information systems for better decisions and outcomes.

"These sobering data not only point to the impact of the pandemic but also to the need for all countries to invest in more resilient health systems that can sustain essential health services during crises, including stronger health information systems," said Dr Tedros Adhanom Ghebreyesus, WHO director-general.

"Measurement of excess mortality is an essential component to understand the impact of the pandemic," said Dr Samira Asma, assistant director-general for data, analytics and delivery at the WHO. 

"Shifts in mortality trends provide decision-makers information to guide policies to reduce mortality and effectively prevent future crises."

(With input from Xinhua)