COVID-19 ground zero boasts low SARS-CoV-2 seroprevalence

Seroprevalence of antibodies against SARS-CoV-2 remains low in Wuhan, China, despite being the site where the novel coronavirus disease (COVID-19) was first detected, a recent study has found.

“Our results suggested that most of the populations of Wuhan remained uninfected during the early wave of COVID-19. Effective [control of] SARS-CoV-2 spread in China was also evidenced by the extremely low antibody prevalence among donors in Shenzhen and Shijiazhuang,” the researchers said.

The study included 38,144 healthy blood donors from the Wuhan, Shenzhen, and Shijiazhuang cities in China. Enzyme-linked immunosorbent assays were performed to quantify SARS-CoV-2-specific immunoglobulin (Ig) M and G antibodies. A pseudotype lentivirus-based neutralization test was used to confirm the presence of neutralizing antibodies.

Overall, 544 samples were positive for antibodies against SARS-CoV-2, yielding a seroprevalence rate of 1.43 percent. Most of these samples (n=463; 2.60 percent) were from Wuhan. Shenzhen and Shijiazhuang had very low seroprevalence rates of 0.396 percent and 0.399 percent respectively.

Subsequent tests—including detection of antibodies against the spike protein or nucleoprotein and neutralization assays—found a total of 398 donors with antibodies capable of neutralizing the virus.

The resulting age- and sex-adjusted seroprevalence rates among 18–60-year-olds were 2.66 percent in Wuhan, 0.033 percent in Shenzhen, and 0.0028 percent in Shijiazhuang, suggesting very low overall rates of infection.

“As most of the population of China remained uninfected during the early wave of the COVID-19 pandemic, effective public health measures are still certainly required to block viral spread before a vaccine is widely available,” the researchers said.