China’s worrying flu positivity rates 13 times higher in a month

China continues to report an increase in influenza virus cases countrywide even as the warmer weather returns, with one in two people examined at hospitals with cold symptoms testing positive for the pathogen.

Influenza positivity rates at hospitals monitored by the Chinese Center for Disease Control and Prevention in the week ending March 12 climbed to 53.2%, about 13 times higher than a month earlier, latest data show. In contrast, positivity rates for Covid-19 remain suppressed at 2.7% and the country had not reported any coronavirus-related deaths for three weeks as of March 16.

Despite the low rate of Covid infections, genetic sequencing in recent weeks shows more subvariants including BQ. 1 and XBB are emerging in China. The explosive outbreak that spread after Beijing’s December pivot from Covid Zero and infected some 80% of the country’s 1.4 billion people was driven mainly by earlier omicron sub-lineages BA.5 and BF. 7.

The ongoing flu outbreak has spurred a scramble for the antiviral drug oseltamivir. Average daily sales of the treatment ballooned more than 100 times in March from a year earlier on China’s popular online marketplaces. The sudden surge in demand has led to temporary shortages in hospitals and pharmacies in parts of the country.