"The difference between the first and second wave may be due to changes in the test criteria. In the first wave, there was a shortage of test equipment, and patients, risk groups and healthcare personnel were prioritised for testing. In the second wave, close contacts and people with mild symptoms could also be tested. " so I'll use the figures from the second wave for the risk.
How many people have these jobs? The US bureau of Labour Statistics has good numbers on occupations here
I took all these jobs and got the numbers of US workers with them and their chance of getting ill. It works out that about 10% of workers account for 30% of cases (in workers). That is still about 16 million people. But it does give a possible next group for vaccines after medical workers. I put the combined risk and numbers employed data into a spreadsheet here