It’s been a hectic morning for Guadalupe Serna. She drives for Lyft in Las Vegas, Nevada and the city is almost fully reopened for tourism.

There’s a volleyball tournament in town, concerts, and thousands of visitors flying here every day to gamble. But all those tourists are bringing more than just their money with them.

Cases are rising in several states, like Nevada, where vaccinations lag and the Delta variant is spreading. It now accounts for half of U.S. cases.

Nevada is among the first states to request one of the CDC's new COVID-19 "strike teams" to help reduce infections and increase vaccinations, specifically in Las Vegas.

Nevada’s governor asked for help from the federal government last week to deal with a recent rise in coronavirus cases and hospitalizations in the state, highlighting the challenges facing states with largely unvaccinated populations now that the pace of inoculations has slackened.

Right now, only those ages 12 and older can get the vaccine. It is still unclear when younger kids will be able to receive theirs.

COVID-19 is spreading fastest in wealthy suburbs in the west and south Las Vegas Valley, as a highly contagious strain establishes a growing foothold.

The delta variant has health officials on alert for the uptick in COVID-19 cases. Nevada is reporting more than 100 confirmed cases.