Ajay Rajadhyaksha is global chair of research at Barclays.

Having seemingly successfully beaten back Covid — cases were below 100 last week, in a country of 1.4bn — China announced that it was open for business again. Can it last? Already, the signs are ominous.

Shanghai officials this week increased testing capacity and unveiled new lockdown measures, because they found just seven new Covid infections outside of government-mandated quarantine sites. Beijing officials have stated that the threshold for unwinding curbs is zero new community cases for seven consecutive days.

These are incredibly exacting standards, far more stringent than the rest of the world.

The US saw a peak of nearly a million daily cases in early 2022. Even in May, US cases averaged over a hundred thousand, but there were no restrictions in the country. France’s 2022 peak was over half a million per day. The country is still seeing 20,000 cases, while also embracing a tourist boom. In the world’s major economies, restaurants are booked, cruise ships are filled up, and tourists are out and about. People and governments have thrown off Covid restrictions, even when cases spike.

With one giant exception. Why is China reacting so strongly to Covid cases, relative to everyone else?

After all, recent variants have been extremely contagious, but also less virulent. Western hospital systems have not remotely been overrun, despite sky-high case numbers. As the pandemic turns endemic, why hasn’t China decided to live with Covid, as the rest of the world has done?

First, China is the only major country that has never had a significant Covid wave. The US had more than a million cases a day in 2021. The UK and continental Europe saw similar large waves at different times last year. India had a horrific surge last spring.

By contrast, China’s peak was the 25,000-30,000 cases the country saw this April, a tiny number for such a large country. The World Health Organization recently estimated that more than two-thirds of the world’s population have significant levels of Covid-19 antibodies. A country without a significant Covid wave, though, is unlikely to be part of this group.

Second, China is behind in vaccinating its elderly population. In this regard, there are parallels between Hong Kong and the mainland. Hong Kong registered the most deaths per million people in 2022 due to Covid — almost 25 times that of Singapore. It was because Hong Kong’s elderly had lower rates of vaccination than the overall population — a surprising occurrence given that the rest of the world prioritised vaccinating older people from day one.

Estimates are that less than 60 per cent of Hong Kong’s elderly were vaccinated by the first quarter of 2022, as opposed to over 80 per cent of the general population. China is similar. A little over 50 per cent of people aged 80 and over on the mainland had their primary vaccinations by March. Less than 20 per cent also had a booster. Chinese officials estimated in March that 52mn people aged 60 and above had not been fully vaccinated.

Finally, look at the experience of China’s neighbours in 2022, when very contagious but less dangerous variants started to take over. South Korea had over 400,000 daily cases in February 2022. This in a developed country with high vaccination rates. Japan saw a peak of over a 100,000. The new variants are contagious enough that if zero-Covid restrictions were dropped in China, cases would probably spread like wildfire.

And while many people in the rest of the world will shrug off new infections thanks to vaccinations and prior exposure, China’s elderly at-risk population — lacking antibodies and often not fully vaccinated — is vulnerable. And that is why China has stuck to its zero-Covid policy, despite the economic costs.

This suggests that we likely haven’t seen the last of the lockdowns. After all, the zero-Covid policy has worked in keeping cases down, and Chinese officials have repeatedly proclaimed it a success.

The less than hundred cases a day that the country is currently seeing is an incredibly low number. But that’s precisely the point — the only way to keep cases at such low levels is through continually rushing to impose new physical isolation and testing measures wherever cases spike. And the variants are contagious enough that if a few cases pop up, Chinese authorities will have to lock those areas down; otherwise a few dozen will become tens of thousands very quickly.

From a health standpoint, China has an impressive record of managing Covid. Adding up government statistics the world over, almost 7mn people have officially died due to Covid, including more than a million Americans. Other estimates are higher; the World Health Organization’s estimate is that there have been 15mn Covid deaths. In contrast, China’s Covid losses are a few thousand.

But this also means the country is now at a very different stage of the Covid cycle than the rest of the world. 2022 is likely to be a year of revolving Covid lockdowns in China, regardless of the mounting economic cost.