Uninstalling McAfee before Installing Vista

I ran the Windows Upgrade Advisor and said I need to Uninstall Mcaffe before installing Vista. But as you go through the installation of vista I read that you can be online so updates can install this is the option I will choose when installing. But if you go online when installing Vista will you get virus's ? I know that the Windows Firewall will be turned on after installation. Thanks any comments welcome