China on Tuesday said only Covid-19 deaths from "respiratory failures" will be included in the official death toll, as the country witnessed a massive spike in infections fuelled by new variants of the Omicron strain.

Beijing, which is hit by the BF.7 variant of the Omicron strain, has announced five more deaths in addition to the two on Monday, the first official fatalities since the government abandoned its stringent anti-virus controls earlier this month following widespread anti-government protests against the Zero-Covid policy.

According to health officials, Chinese cities are currently hit by the highly transmissible Omicron strains mainly BA.5.2 and BF.7.

On Tuesday, China's National Health Commission (NHC) clarified that only Covid-19 patients who die from respiratory failure will be counted in the official death toll.The clarification follows media reports that many more died after becoming infected amid rising demand at funeral homes and crematoriums, Hong Kong-based South China Morning Post newspaper reported.

The commission issued a notice clarifying how it is calculating the death toll from the virus in what it calls a "scientific and realistic manner".

The new guidelines narrow the criteria for counting Covid-19 deaths, removing cases such as patients who had a heart attack after becoming infected.

"Deaths caused by pneumonia and respiratory failure resulting from Covid-19 will be classified as Covid-19 deaths, while deaths caused by other underlying diseases, such as cardiovascular and cerebrovascular diseases, will not be counted as Covid-induced deaths," the Post quoted Wang Guiqiang, an adviser to the NHC and director of the infectious diseases department at Peking University First Hospital as saying on Tuesday.

Wang said Omicron, the variant fuelling the current surge in cases, was becoming less lethal and China was increasing the vaccination rate, which meant the pattern of infections and deaths were changing.

In the initial stages of the outbreak, which began in the central city of Wuhan in December 2019, most deaths were caused by coronavirus-induced respiratory failure.But now, he said, Omicron mainly attacks the upper respiratory tract and while some patients may develop pneumonia, few will suffer respiratory failure.

"From a clinical practice, it can be seen that the main cause of death after infection with Omicron is a chronic illness, while respiratory failure directly caused by the Covid-19 infection is rare," Wang said.

"We don't avoid [talking about] the hazards of Covid-19, but at the same time we must view it from a scientific perspective," he said.

When asked about China's reportage of Covid-19 death, Benjamin Cowling, head of epidemiology and biostatistics at the University of Hong Kong, said the number of deaths reported since the restrictions eased was a bit smaller than we might expect, but consistent with the very low rate of PCR testing in China now.

"I think there are deaths due to Covid-19 in China which are not laboratory confirmed and therefore not counted in the official tally, but that is true anywhere in the world and it's not something unique to China," he told the Post on Monday.

Meanwhile, Beijing is experiencing a massive wave of the BF.7 Omicron virus.

According to one estimate, over 70 per cent of Beijing's population has been hit by the virus, which confined millions of people to their homes.

Those who contracted the virus included scores of Beijing-based diplomats, their families as well as journalists besides a vast number of the city's population.

For days together Beijing wore a deserted look with less traffic on city roads.

The striking feature of the crisis is that China has lost count of the cases as it stopped public testing for nearly two weeks.

As a result, people are forced to buy self-testing antigen kits which are now being sold in black at exorbitant prices.

Hospitals in Beijing are facing staff shortages and an influx of patients since the policy U-turn, the Post report said.

Many residents in the capital are struggling to get medicines, with long queues at hospitals and a spike in the calls for ambulances.

With confusion about the government's handling of the virus, there is a growing concern about how to protect millions of China's elderly people, the majority of whom have not been vaccinated.

The elderly, aged 65 and above, exceed 200 million people, accounting for 14.2 per cent of the Chinese population as of the end of 2021, the state-run Global Times newspaper reported.

Data showed elderly people who have underlying diseases and complications such as cardiovascular disease, diabetes and chronic respiratory diseases are susceptible to severe cases.

"It's necessary to set up a hierarchical diagnosis and treatment system for elderly people, which could diagnose seniors and treat them better based on their health status," Chen Erzhen, a deputy head of Ruijin Hospital in Shanghai said.

Leading Chinese epidemiologists say the epidemic will peak in January and February, although the number of infections will continue to increase in the short term.