Photo: Xinhua

 The medical worker in Northwest China's Shaanxi Province, who was confirmed as a COVID-19 case on Thursday, had completed vaccine inoculation before contracting the virus, media reported on Saturday. Experts noted that there is no vaccine that can effectively fend off the virus 100 percent, and the public shouldn’t worry over its efficacy based on a single contraction case. 

Prior to her infection, the patient had been inoculated with two shots of COVID-19 vaccine in end-January and early February, Jiankang Shibao learned from the hospital’s lab where she worked on Friday. 

The case was believed to have been infected from an accidental exposure in an enclosed COVID-19 testing ward in No.8 Hospital in Xi'an, one of the designated hospitals for treating COVID-19 patients in the city, according to local health authorities. 

The infection, which drew an end to the 31-day streak of zero new domestically-transmitted cases in the Chinese mainland, has sparked concerns over whether it has indicated the inefficacy of domestically produced vaccines.

Tao Lina, a Shanghai-based vaccine observer, refuted the concern. “There is no vaccine in the world, whether mRNA or inactivated, that can vow an absolute safety from getting an infection after vaccination,” he told the Global Times on Saturday. 

Zeng Guang, chief epidemiologist at the Chinese Center for Disease Control and Prevention, echoed Tao’s remarks, saying that China-developed vaccines have been given to tens of millions of people both at home and abroad, which already provides sound proof of its efficacy and safety, and the public should not worry over one single infection case.

Tao added that since the case was responsible for collecting nucleic acid test samples of imported infected patients and carrying out laboratory tasks at the enclosed labs, she was constantly surrounded by a virus-filled environment with relatively high density and high risk of exposure to the virus, which could have resulted in her infection.

While not worth panicking for, experts reminded people to stay vigilant even though they have received the vaccine, especially key groups such as medical workers, who tend to be exposed to the virus more frequently than others. 

A total of 4,669 people in Xi’an, who were identified as close contacts or relevant personnel to the case, were tested for COVID-19 by Friday, all returning negative results. The 33 colleagues from the same laboratory of the case received nucleic acid tests twice, showing negative results as well, China National Radio reported on Friday.

Zeng said the incident has called for a more extensive study on the post-vaccination reactions, for example, how severe would the case get, and whether the virus’ contagiousness has weakened.