Chinese authorities announced this week they are lifting lockdowns in at least seven districts in the wake of protests against the government's controversial zero-COVID strategy.

According to experts, China's zero-COVID strategy was a good approach at the start of the pandemic because it kept cases low. But the world has changed over the last three years —  health services are much better equipped to deal with outbreaks and COVID treatments.

"We now have the tools to address COVID as a public health concern. We have vaccines, antiviral drugs and a huge amount of knowledge about how to treat people and manage outbreaks in the community," said Michael Head, an epidemiologist at University of Southampton in the United Kingdom.

In essence, other countries with less stringent lockdowns created high levels of COVID protection in the population from two sources: natural exposure to coronavirus infection, and through mass vaccination drives.

"A small silver lining of the extensive spread of COVID in Europe is that we have a memory in our immune system. That's the theory, anyway," Head told DW.

But because China has energetically pursued zero-COVID policies since the pandemic began, their population has had very little natural exposure to infection, especially when it comes to the highly contagious omicron variant.

China's booster strategy falls short

Experts say China's transition to living with COVID must rely on vaccination. Unfortunately, the country's vaccination program hasn't been so effective, especially when it comes to administering booster jabs to older people.

"Vaccines are great at giving you protection against severe illness, but they don't give you sterilizing immunity. You need boosters to keep your immunity up," said Keith Neal, emeritus professor in epidemiology at University of Nottingham in the UK.

Sterilizing immunity, explained Neal, is when the immune system prevents the virus from infecting the host, thereby stopping transmission. Current vaccines do not provide sterilizing immunity.

As of August 10, 2022, the full vaccination rate in China was 85.6% and the booster vaccination coverage was only 67.8% for adults aged 60 or over, significantly lower than in countries like Germany (91.2% and 85.9% respectively).

"There was a vaccine campaign in China that prioritized young people to keep workers healthy. Older people are less vaccinated than other countries. This is a problem, as risk of death from COVID-19 increases significantly with age," Neal told DW.

Vaccine hesitancy in China?

Observers suggest that lockdowns, when people only left their homes to get food, would have been the perfect time for mass vaccination strategies . So why are booster rates lower in China?

For one, experts suspect vaccine hesitancy might be an issue among adults. Reliable data is hard to come by, but one study suggests vaccine hesitancy among teachers in China is at around 32%.

The study suggests vaccine hesitancy largely comes from concerns about personal safety.

"Chinese vaccines [Sinovac and Sinopharm] are not bad, perhaps similar to AstraZeneca's vaccine, but have lower  effectiveness than mRNA vaccines like [those from] Pfizer and Moderna, especially when it comes to omicron," said Head.

According to Head, a specialist in vaccine hesitancy, political affiliation and distrust of the government is a predictor of vaccine hesitancy. The rare appearance of protests right now in China over zero-COVID strategies indicate that people's trust in authorities to deal with the pandemic may be at an all-time low.

"Health promotion is going to be key going forward to increase vaccine uptake. How to do this is a tricky thing to solve, especially if it comes from a government many distrust," Head said.

New variant cooking pot?

With low natural immunity and poor booster uptake among at-risk groups, experts suggest easing local lockdowns might spell disaster for China, especially with population-level protection against the omicron variant being low.

"Omicron has an R0 of 10, meaning it's highly infectious. Without sterilizing immunity, you haven't got a cat in hell's chance of stopping it," said Neal.

Both Neal and Head said quite severe outbreaks in Chinese regions are probable. They predict high numbers of severe cases in those with low immunity in the short run, as well as major long-term impacts of long COVID.

Aside from the immediate public health concerns, an uncontrolled outbreak runs the risk of new COVID variants and subvariants developing.  After all, this is how the previous variants occurred. Delta, for example, came out of a COVID crisis in India, alphain the UK.

"Uncontrolled outbreak in China would increase the risk of the emergence of new variants. China and the world will be keeping an eye on this," said Head.

Will scrapping zero-COVID affect other countries?

If outbreaks in China do occur, will other countries be at risk? Experts suggest travel restrictions in China might keep that from happening.

"There isn't a lot of travel in and out of China — it's like a giant island. So if new variants do appear, they're likely to stay contained," said Neal.

In the end, what happens to those contained within China will come down to political decisions from the Chinese Communist Party.

"China has a political problem here. They wedded themselves to zero-COVID. They wedded themselves to 'we have the best system in the world to look after you.' They wedded themselves to less effective Chinese vaccines," said Neal.

Whether China will open up their COVID strategy to purchase Western vaccines and employ less stringent lockdown measures remains to be seen.

Edited by: Carla Bleiker