Public Health England’s new study revealed that two doses of Pfizer’s vaccine provided 88% effectiveness against the B.1.617.2 variant, commonly known as the Indian variant.

AstraZeneca’s jab, meanwhile, showed 60% effectiveness, also after two doses.

According to the PHE study, the difference between the two jabs could be explained by the delayed rollout of the AstraZeneca vaccine, not allowing it to reach maximum effectiveness.

Both vaccines were 33% effective against symptomatic disease arising from the Indian variant three weeks after their first dose.

Mary Ramsay, head of immunisation at PHE, noted that two doses of either vaccine would offer “high levels of protection against symptomatic disease from the B.1.617.2 [India] variant and we expect the vaccines to be even more effective at preventing hospitalisation and death.”

Given the strong vaccination rate so far in the U.K., 1-in-3 people in the country are protected against the new variant, according to Health and Social Care Secretary Matt Hancock, who described the new data as “ground breaking.”

In the week to May 19, cases of the Indian variant in the U.K. jumped 160% to 3,432 from 1,313. A report in the medical journal BMJ blamed the surge on failures in the government’s track and trace system. Most cases of the variant are in northwest England but infections have been noted across the country.

The effectiveness of the vaccines against the Indian variant is hopeful news for the U.K., which has been removing lockdown restrictions in stages, most recently reopening restaurants and pubs from May 17. The country has marked June 21 as the day when all restrictions are finally dropped.

British Prime Minister Boris Johnson said he would reveal by the end of the month if lockdown could be lifted on June 21 as planned.