evidence: If you have a fever, remain in quarantine until the fever resolves. [...] Vaccinated people are less likely to develop severe disease. However, if you do test positive, keep an eye out for signs of a worsening infection. These symptoms include: [...] As medical professionals better understand COVID-19 and how vaccines affect how easily the virus is spread, advice on quarantine and isolation is changing. Today, the CDC has less strict quarantine requirements for people who have been vaccinated.