The United Kingdom’s top drug regulator said Friday that the vaccines for the coronavirus disease 2019 (Covid) supplied by two top drug firms are very safe and have so far produced only mild side effects.

The Medicines and Healthcare Products Regulatory Agency (MHRA) announced its findings after studying tens of thousands of people who have received the vaccines from Pfizer-BioNTech and AstraZeneca-Oxford University.

The MHRA said more than 10 million doses of the vaccines have been given in Britain so far and just three in 1,000 recipients have experienced side effects.

“The safety of these vaccines remains as high as expected,” the regulator said in a statement.

“The safety profile of the vaccines remains positive and the benefits continue to far outweigh any known side effects,” it added.

Friday’s assessment doesn’t include data for Moderna’s vaccine, which has also been approved for use in Britain.

The MHRA said that almost all of the side effects were mild and included sore arms and flu-type illness.

“The data we have collected provides further reassurance that the Covid-10 vaccines are safe and continue to meet the rigorous regulatory standards required for all vaccines,” said MHRA chief Dr. June Raine.

“Our priority is to ensure the public have safe and effective vaccines and we will continue to analyze, monitor and review all the safety data for these vaccines,” the official said.

AstraZeneca and Oxford said this week that late-stage clinical tests showed their vaccine is about 76-percent effective overall, and 100 percent effective in preventing severe cases of Covid-19. Pfizer and BioNTech said their vaccine is 95-percent effective in blocking the virus.

Most experts have said that available evidence so far shows that the existing vaccines will also be effective against variant strains of the coronavirus.