Two new British studies provide some early hints that the omicron variant of the coronavirus may be milder than the delta version.

Scientists stress that even if the findings of these early studies hold up, any reductions in severity need to be weighed against the fact omicron spreads much faster than delta and is more able to evade vaccines. Sheer numbers of infections could still overwhelm hospitals.

Still, the new studies released Wednesday seem to bolster earlier research that suggests omicron may not be as harmful as the delta variant, said Manuel Ascano Jr., a Vanderbilt University biochemist who studies viruses.

“Cautious optimism is perhaps the best way to look at this,” he said.

An analysis from the Imperial College London COVID-19 response team estimated hospitalization risks for omicron cases in England, finding people infected with the variant are around 20% less likely to go to the hospital at all than those infected with the delta variant, and 40% less likely to be hospitalized for a night or more.

That analysis included all cases of COVID-19 confirmed by PCR tests in England in the first half of December in which the variant could be identified: 56,000 cases of omicron and 269,000 cases of delta.