Analysis by Airfinity shows between 1.3 and 2.1 million lives could be at risk if China lifts its zero-COVID policy given low vaccination and booster rates as well as a lack of hybrid immunity.
Airfinity’s risk analysis uses cumulative peak cases and deaths from Hong Kong's BA.1 wave as a proxy for mainland China.
Hong Kong took a zero-COVID approach for the first two years of the pandemic. Therefore, when the more transmissible Omicron BA.1 sublineage hit back in February, population immunity from infection was low. This, combined with a low vaccine coverage, led to a huge wave of both infections and deaths, especially amongst the elderly.
Mainland China has very low levels of immunity across its population. Its citizens were vaccinated with domestically produced jabs Sinovac and Sinopharm which have been proven to have significantly lower efficacy and provide less protection against infection and death.
This vaccine induced immunity has waned over time and with low booster uptake and no natural infections, the population is more susceptible to severe disease. China’s current booster uptake in over 80's is 40%, whilst Hong Kong’s primary series uptake was 34% back in February 2022 when it saw a large spike in cases due to the BA.1 omicron variant.
China’s zero-COVID strategy also means the population has almost no naturally acquired immunity through previous infection. As a result of these factors, our analysis shows if mainland China sees a similar wave to Hong Kong’s in February, its healthcare system could be pushed to capacity as there could be between 167 and 279 million cases nationwide, which could lead to between 1.3 and 2.1 million deaths.
To date, China has reported total cumulative deaths from the pandemic to be 5,232. In comparison India has officially reported 531,614 deaths and the U.S. has reported 1.08 million total deaths. Airfinity’s Head of Vaccines and Epidemiology Dr Louise Blair says, “It is essential for China to ramp up vaccinations to raise immunity in order to lift its zero-COVID policy, especially given how large its elderly population is. Subsequently, China would need hybrid immunity to allow for the country to brace future waves with minimal impact. This has proven effective in other countries and regions; for example, while Hong Kong efforts to vaccinate the vulnerable prior to opening likely only dampened the impact of its first wave, its protection has been enhanced by hybrid immunity from mass infection leading to much less impactful and deadly COVID-19 waves.”