(Bloomberg) -- China is warning it faces a steep surge in Covid cases as the country rapidly dismantles pandemic controls and embraces a faster reopening than some experts had expected.

The sudden move away from Covid Zero has left many people bewildered and a surge in infections is “surely unavoidable,” Zhang Wenhong, one of China’s top Covid advisers, wrote in an opinion piece published by Caixin on Tuesday. The country will likely see a large initial peak, followed by significantly weaker second and third waves, he wrote, citing the experience of other countries. 

The comments come after China scrapped almost all of its internal virus curbs last week, in a sudden U-turn that leaves only strict border controls as the last vestige of the Covid Zero policy that isolated the country for three years. 

The swift reopening has surprised many China watchers and stoked concerns that the world’s second-biggest economy faces a rough road ahead as officials haven’t put in place measures to deal with the inevitable squeeze on the health-care system that comes from soaring cases and fatalities, particularly among the vast nation’s under-vaccinated elderly.

Read more: End of Covid Zero Risks Overwhelming China With Infections

“If the majority of people become infected within just a few months, the medical system will be visibly affected,” Zhang wrote in the article that was also published on the WeChat account of Huashan Hospital, where he is the head of the infectious disease department. Along with other experts, he called for government departments to put in place measures to cope with the increase in infections and urged hospitals and drug providers to have supplies in reserve.

Winter Threat

As well as the speed, the timing of the policy shift has caught some experts off guard. Freezing winter temperatures are descending on China’s north, which will likely speed the spread of both Covid and other respiratory illnesses. And little progress has been made in increasing elderly vaccination rates — just 40% of people over 80 have had a booster. 

While China has built massive centralized quarantine facilities through the pandemic, officials have only recently vowed to add more hospital beds, especially in intensive care units.

The current path contrasts with gradual approaches in much smaller, and more developed, countries like Singapore and New Zealand, which opened up in phased manner, underpinned by a high vaccination rate to limit deaths. Even then, both places saw significant strain on the health-care system due to infection surges after opening up.

Elsewhere, Hong Kong continued toward its own reopening, announcing Tuesday it would scrap a ban on international arrivals going to bars or eating at restaurants.

Read more: Covid Surge Sparks Tumult in Poorly Prepared China Hospitals

The medical system is already showing signs of strain. 

Many Chinese, fearful of the virus after three years of state media propaganda about its risks, are flocking to hospitals and struggling to find medicine. Some facilities have asked staff to come to work even if they have Covid, as long as their symptoms are mild, to deal with a worker shortage. 

State media is asking people in Beijing — which is seeing a widespread surge — to avoid calling the capital’s emergency medical hotline unless they’re severely sick. The capital’s testing apparatus has effectively collapsed due to the number of infections, with official case numbers far removed from the reality on the ground. 

‘Bumpy’ Reopening

There are already signs of what Goldman Sachs Group Inc. President John Waldron predicts will be a “bumpy” reopening, that could add to risks to global growth. Nomura International echoed that call, warning China faces a painful period as it doesn’t appear to be well prepared for the inevitable massive wave of infections. 

Bloomberg Economics predicts the current rapid pace of easing will probably give way to a more measured process, particularly if there are strains on medical resources, and it may take until late in the second quarter of next year for a proper end to Covid Zero to be achieved.

Markets trading so far this week suggests equity investors are growing more cautious. The Hang Seng China Enterprises Index of Chinese stocks listed in Hong Kong is down about 2.4% since its close on Friday after surging over 14% in two weeks. A sharp increase in Covid infections following the abrupt end of pandemic rules suggests investors may need to pare back on reopening trades, according to Morgan Stanley. 

Read more: Goldman’s Waldron Says ‘Bumpy’ China Reopening a Growth Risk

Commentary like Zhang’s have become increasingly frequent across Chinese media, with a notably softer tone on Covid being struck in the country’s vast propaganda apparatus. 

State-run media that have spent most of the past three years trumpeting the success of Covid Zero and excoriating Western nations that have shifted to living with Covid, are now front and center in preparing the country’s 1.4 billion residents for their likely infection with the virus.

Virus Wave

As much as 60% of China’s population could be infected at the peak of the first wave, Feng Zijian, the former deputy chief at the Chinese Center for Disease Control and Prevention was quoted by Beijing Radio and Television as saying at a Tsinghua University seminar on Dec. 6. 

Feng was also reported to have called for a new round of booster shots that target new variants as the shots received so far provide less protection against omicron, even though they can still lower the risk of severe infection.

Currently, China is seeing different Covid subvariants in different parts of the country, Qiao Jie, dean of Peking University Third Hospital, said at a briefing by the State Council’s Covid taskforce. People infected in the north are showing worse symptoms, said Qiao, who is a reproductive and obstetrics specialist.

Elderly at Risk

The country’s low rate of vaccination among its elderly is a core concern of health experts, with the experience of other places, in particular Hong Kong earlier this year, showing the group is especially vulnerable to severe illness and death from Covid. 

Elderly who have stable underlying health issues are fit for Covid vaccination, Wang Huaqing, chief immunization expert at the Chinese Center for Disease Control and Prevention, said at Tuesday’s briefing. 

There are no mandates requiring vaccination for residents at care homes in China, as well as workers and visitors, though the National Health Commission has increasingly urged them to get vaccinated.

“If we could delay the general infection curve of elderly — even by a month or two — the immunologic barrier of the whole population will be stronger,” wrote Zhang, urging senior citizens to get inoculated as soon as possible. “Medical resources will be more adequate after the peak of the first wave and elderly at nursing homes will have more abundant treatment resources.”

Read more: China’s Covid Exit Hinges on Seniors Who Don’t Want Vaccines

--With assistance from Shikhar Balwani.

(Updates to add details throughout.)

©2022 Bloomberg L.P.