Chinese epidemiologists said in a peer-reviewed medical journal that the strict, comprehensive pandemic control strategies in Shanghai will buy time for full vaccination coverage.
Without strict public health measures, the number of severe to critical cases and the resulting death toll could be high among unvaccinated older people, according to a study published recently in Lancet.
Those measures include large-scale viral nucleic acid and antigen screening, quarantine of infected cases and close contacts in shelter hospitals and hotels, respectively, and lockdown of districts with severe outbreaks, according to the study.
The researchers from the National Research Center for Translational Medicine and Fudan University compared the fatality rate in Hong Kong during its recent wave of the COVID-19 pandemic and that in New Zealand.
In Hong Kong, the crude case fatality rate among those older than 60 years was 2.7 percent, and 19.3 percent of this age group has not been vaccinated. Comparatively, only 2 percent of New Zealand's population older than 60 years has not been vaccinated, and they reported a low COVID-19 crude case fatality rate of 0.07 percent.
In Shanghai, with a population of 25 million, the overall vaccination coverage has exceeded 90 percent, but vaccination coverage has remained low with approximately 62 percent of 5.8 million people older than 60 years being vaccinated, and only 38 percent have received a booster vaccination, according to the study.
As of May 4, among the 503 people who died with or from COVID-19 in Shanghai, only 25 patients had received at least one dose of the COVID-19 vaccine, said the study.
The strict and comprehensive pandemic control strategies in Shanghai are therefore to reduce the number of people infected and to provide early diagnosis and appropriate treatment for severe COVID-19 so that the case fatality rate can be minimized, the researchers said.
The researchers said that local citizens have suffered in their daily lives from inconveniences of the lockdown, but the strategy has shown promising results, as indicated by R0, an index for the transmission rate, dwindling from 9.5 at the beginning of the wave to 0.67 on May 1.
The persistence of dynamic zero COVID-19 community transmission in Shanghai and other cities will overcome weak links in the immunological barrier in populations across the country, according to the study.
The next challenge is to enhance the communication between healthcare providers and the public to overcome the vaccine hesitancy and make vaccination services accessible to all people, the older and vulnerable people, in particular, said the study.