Vaccinated people need not quarantine post COVID-19 exposure, CDC says

People who have received the full course of COVID-19 vaccines can skip the standard 14-day quarantine after exposure to someone with the infection as long as they remain asymptomatic, US public health officials advised.

The US Centers for Disease Control and Prevention (CDC) said on Wednesday the vaccines have been shown to prevent symptomatic COVID-19, thought to play a greater role in the transmission of the virus than asymptomatic disease.

"Individual and societal benefits of avoiding unnecessary quarantine may outweigh the potential but unknown risk of transmission (among vaccinated individuals)," the CDC said.

The agency has laid down strict criteria for people who would no longer have to quarantine after the vaccinations, including having received both doses of a two-dose vaccine.

People who choose not to quarantine should do so only if they received their last dose within three months, and should only avoid 14 days quarantine after their last shot, the time it takes to develop immunity, CDC said.

Fully vaccinated persons who do not quarantine should still watch for symptoms for 14 days following an exposure.

Two-dose vaccines from Pfizer Inc and Moderna Inc have been authorized for emergency use in the United States. Johnson & Johnson applied for a US authorization of its single-dose shot last week.