Italian officials who screened 556 airline passengers from two Chinese provinces in late December found that almost a quarter of them tested positive for SARS-CoV-2, the virus that causes COVID-19, with one flight having 42% of passengers infected, according to a report yesterday in Eurosurveillance.
Authorities conducted the screening from Dec 26 to Dec 29 after Omicron cases spiked dramatically in Beijing and other Chinese cities. The screening took place at two major airports: Fiumicino Leonardo da Vinci in Rome and Malpensa in Milan.
Of the 556 passengers from China screened, 126 (22.7%) tested positive via polymerase chain reaction testing. The proportion testing positive for SARS-CoV-2 per flight ranged from 11% to 42%. The flights originated from either Nanjing in Jiangsu province or Hangzhou or Wenzhou in Zhejiang province. Both those provinces are in eastern China.
Whole-genome sequencing of samples from 61 COVID-positive patients revealed that three Omicron sublineages were dominant: BA.5.2.48, BF.7.14, and BQ.1.1. The authors note that BF.7 has been circulating in United States and Europe since August 2022 and in Inner Mongolia since September 2022.
The authors conclude, "Our findings agree with sequencing data released from China and underline the relevance of genomic surveillance to detect evolution of dominant lineages in a large ecological setting. Such [a] setting, consisting mostly of a highly vaccinated but infection-naïve population is so far unprecedented in the COVID-19 pandemic."