Virus and fear surge in China: what’s happening and why?

China had been following a zero-Covid policy for the last three years, which involved extremely restrictive measures to deal with any surge in cases. Every known case, even asymptomatic, was mandatorily hospitalised, small outbreaks triggered hard lockdowns, and suspected cases, and all their contacts, were kept under long isolation. Foreign travellers had to mandatorily go through 10 days of isolation.

The measures were painful but effective in keeping a check on the spread of the virus for three years. However, it also meant that a large proportion of the population was never infected by the virus, and had no natural immunity, thereby rendering it extremely susceptible. So, once the virus was able to break through the defences, as it sometimes did, it spread rapidly in the population. That is what happened in March-April this year when China saw an explosion of cases for the first time.

Fast-transmitting variant

The dominant virus strain in China is BF.7, a sub-variant of Omicron that has been in circulation for over a year now. There are over 500 Omicron sub-variants currently in circulation.

BF.7 is the name for the BA.5.2.1.7, which itself has evolved from the BA.5 sub-variant. BF.7 is not unique to China. It accounted for over 5 per cent of the cases in the US in October and over 7 per cent of the cases in the UK.

But the surge in China has nothing to do with the type of variant circulating there, according to virologist Dr Ekta Gupta.

“There is no scientific evidence to suggest that there is one particular variant that is driving the surge in China. Neither is there evidence to suggest that any new variant is the cause. If you look at the Gisaid data (a global database of Sars-CoV-2 genomes), nothing vastly different has been uploaded from the country,” virologist Dr Gupta said.

She said it was the large susceptible population that was the key driver of the surge.

“From what I can understand, the strict lockdowns in China meant that a huge proportion of the population did not get the infection. We have seen that a natural infection provides a wider and longer immunity against Covid-19. In India now we are seeing people out and about, even without masks, but we are not reporting a high number of cases because people have a hybrid immunity from natural infection as well as high levels of vaccination,” Dr Gupta said.

Concern for the world

While the surge has remained confined to China, there are fears that it might spread to other countries as well since international travel is back almost to pre-Covid levels now. An even bigger concern, considering that large numbers of infections are taking place in China, is the possibility of the virus evolving into more dangerous variants.

“That is certainly one of the fears. As the virus finds more and more hosts, it has more and more chances of mutating into new forms. And no one can predict how dangerous these new mutations could be,” said Dr Virander Chauhan, former head of the Delhi-based International Centre for Genetic Engineering and Biotechnology.

Grim projections

The surge in China has prompted dire warnings that point to potentially millions of deaths in the country. A report in Nature published on Monday cited a study which said nearly 1 million people could die in China over the next few months. Reuters listed three other recent studies which have projected between 1 million and 2.1 million deaths in China.

While such projections in the past have been way off the mark — one study at the start of the pandemic had said 1-3 million people were likely to die in India by the middle of April 2020 — the situation in China right now is drastically different from what other countries have faced.

China has nearly 1.4 billion people, most of whom are susceptible to infection. The rapid spread of the virus could mean very large numbers of people falling sick at the same time.

The Chinese vaccines, Sinovac and Sinopharm, are also reported to be not very effective. China was the first country to have started vaccinating its people, way back in June 2020. But that also meant that the vaccine was not fully developed at that time.

Vaccines haven’t prevented infections in any significant manner, but they have been quite effective at preventing severe diseases and deaths elsewhere. But this is in doubt in China now. The effectiveness of Chinese vaccines would be the most crucial factor in deciding the outcome of the current Covid crisis in China.