Delta variant poses biggest threat to China since start of pandemic in 2019

China is confronting its broadest coronavirus outbreak since the pathogen emerged in late 2019 after the Delta variant broke through the country’s defences, with cases now in 14 of 32 provinces.

While the overall number of infections — more than 300 so far — is much lower than outbreaks elsewhere, the wide spread indicates that the variant has been on the loose for some time and is alarming officials who wield the strictest containment measures in the world.

It is the biggest challenge for the world’s second-largest economy since the virus was first detected in the central Chinese city of Wuhan in December 2019. China’s strict regulations — including mass testing, aggressive contact tracing, quarantines and occasional lockdowns — crushed more than 30 previous flare-ups.

The arrival of the more infectious Delta variant is testing that approach. The new strain may be exploiting the population’s recent willingness to lower their guards regarding masking and distancing, since much of the country has been Covid-19-free for months. That, with increased travel during summer, created conditions for Delta to gain a foothold.

The initial infection arrived via an overseas flight from Moscow into the eastern Chinese city of Nanjing in mid-July, and took hold there among the airport cleaning staff.

China reported 99 infections on Monday alone, including 44 people who tested positive but have no symptoms. By number of cases, it is the biggest outbreak since the flare-up in Hebei in northern China in January, when 2,000 people were infected. The broad spread is more concerning, with infections having reached the highly protected capital, Beijing, and as far as Hainan province in the south, 1,900km away from Nanjing.

Less able

It remains to be seen if the country’s vaccination rate, close to 60% and among the highest in the world, can slow Delta’s spread and keep serious illness and death at bay. Most of those infected in Nanjing have been immunised. The shots do appear to protect against serious disease, with 4% of those infected battling severe disease so far. Many of them have pre-existing conditions such as asthma, diabetes or high blood pressure, said Guo Yanhong, an official with the National Health Commission, at a briefing in Beijing on Saturday.

While Delta has dented the efficacy of all Covid-19 vaccines, concerns are high that non-MRNA vaccines such as the Chinese ones and AstraZeneca’s shot will be less able to slow transmission.

State-owned Sinopharm said its inactivated Covid-19 shot, a mainstay for the Chinese population, is 68% effective against Delta, citing a study in Sri Lanka. Sinovac Biotech, the other major Chinese supplier of shots, said that sera samples from people inoculated with its inactivated vaccine can still neutralise the Delta strain in laboratory studies, state media Global Times reported, without more detail.

Delta has dented the effectiveness of all Covid-19 vaccines, showing that immunisation alone will not bring the outbreak to heel. Last week, the US Centers for Disease Control and Prevention reversed its earlier position and said fully vaccinated people should go back to wearing masks indoors in places where infections are rising.

Separate cluster

“Delta accounts for 80% of cases in the US, and they reinstituted a requirement for masks,” said Wang Huaqing, chief immunisation expert at the Chinese Center for Disease Control and Prevention, at the Saturday briefing. “That means Delta’s spread is severe and personal protection cannot be slackened even with vaccination.”

Adding to the concern is a separate cluster in the central Chinese city of Zhengzhou — also of the Delta strain — where hospital and cleaning staff have been infected. Cases were reported in the broader Henan province as well, where the ability to curb the virus’s spread may be weakened due to the fallout from torrential rain that has killed nearly a hundred people and destroyed infrastructure.

Residents in Nanjing, where the recent outbreak began, have been placed under lockdown. Also affected are those living in Zhangjiajie, a scenic area famous for its verdant mountain ridges, where a live outdoor performance a week ago with more than 3,000 spectators fuelled the virus’s spread.

Officials in the Chinese capital of Beijing, which has detected five Delta cases, vowed to cut off the virus’ transmission with “fastest pace, strictest measures and the most decisive actions”. It will tighten entry restrictions for those travelling from places now battling outbreaks, and government and state company employees have been barred from leaving the city.

Bloomberg News. More stories like this are available on bloomberg.com