Trials disrupted by the first wave of the COVID-19 pandemic in 2020 are continuing to reopen, but the emergence of two more contagious variants of the SARS-CoV-2 virus resulted in a drop in the rate of recruitment in January, according to data analysis firm GlobalData.

More than 900 disrupted trials had resumed as of Jan. 25, with 79.9 percent of them currently recruiting participants. More than 12 percent have completed recruitment and 0.5 percent of trials have yet to start recruiting participants.

And while the number of trials resuming activity has been increasing, the period between Dec. 23, 2020, and Jan. 25, 2021, saw a decline in the number of trials actively recruiting to 71.9 percent from 74.6 percent in the previous months. Global Data attributes the drop to increased restrictive measures countries have put in place as the new UK and South Africa variants emerged.

The U.S. has the highest number of resumed trials at 87.5 percent, Global Data said, followed by the UK (10.8 percent), Spain (9 percent), France (8.8 percent) and Germany (8.1 percent).

The number of trials completed increased to 12.8 in January from 10.6 percent in 2020.