New mutant strains pose a high risk to society, particularly to unvaccinated people, a government official said.
Dr Farida Al Hosani, spokeswoman for the state health sector, emphasised that those who had not yet been inoculated were at high risk of contracting the coronavirus.
She urged all residents to book vaccination appointments.
"We stress that mutations pose a high risk to society, especially for those who are not vaccinated, so we call upon members of the community who are not vaccinated to take the available vaccinations," the National Crisis and Emergency Management Authority wrote on Twitter after the briefing.
"Studies show that those who are vaccinated with all the prescribed doses of the #Covid19 vaccine and the booster dose are less exposed to infection and complications of the disease, admission to hospitals, reduced hospital stay and no need for respirators," read another tweet.
The government has urged all residents, especially the elderly and chronically ill, to receive a third vaccine shot as a booster.
The booster can be from the same manufacturer as the original shots or, subject to a medical examination, a different vaccine, authorities said.
It was noted during the briefing that case figures had risen after Eid Al Fitr and residents were urged to maintain social distancing even when vaccinated so that the nation could move on to the next step of the recovery plan.
The US reached the grim milestone of more than 600,000 deaths from the virus on Tuesday, according to Johns Hopkins University data. The death rate has slowed from about 100,000 per month during the worst surge in the winter, as the country pushes its vaccination strategy.
More than half of the US population has received one dose of a coronavirus vaccine, and 43.9 per cent are fully vaccinated, CDC data from Tuesday found.
But President Joe Biden's plan to have had at least 70 per cent of the population with one dose by July 4 look unlikely.
"Please, please get vaccinated as soon as possible. We've had enough pain – enough pain," he said in remarks from Belgium on Monday.