Health Commissioner Dr. Mark Levine said the rate of breakthrough COVID-19 cases in Vermont is expected to rise with the emergence of the highly contagious Omicron variant.

Levine said since the beginning of the delta surge, the breakthrough case rate has risen to about 2.4 percent of positive test results. On Monday, the Health Department reported that at least three people have tested positive with the omicron strain.

“To me, this will just be the tip of the iceberg,” he said.

Tim Lahey, an infectious disease physician at the University of Vermont Medical Center, said people who are immuno-compromised are especially vulnerable to breakthrough infections. Lahey said vaccination and booster shots are key to fighting omicron.

“These vaccines still provide incredible protection from hospitalizations and death even from omicron, so there is no better time than yesterday to get vaccinated.”