Israel has reported a decrease in the effectiveness of the Pfizer/BioNTech COVID-19 vaccine in preventing infections and symptomatic illness.
But the country says the shot is still highly effective in preventing serious disease.
The decline has coincided with the spread of the Delta variant - and an end of social distancing restrictions in the country.
The Health Ministry say the vaccine's effectiveness in preventing infection and symptomatic disease fell to 64% since June 6.
But that the vaccine was 93% effective in preventing hospitalizations and serious illness from coronavirus.
It did not say what the previous level was.
A Pfizer spokesperson declined to comment on the data from Israel.
But cited other research showing that antibodies created by the vaccine were still able to neutralize all tested variants.
About 60% of Israel's 9.3 million population have received at least one shot of Pfizer's vaccine.
Causing daily cases to drop from more than 10,000 in January to single digits last month.
Numbers are climbing again though, since the Delta variant began to spread in the country.
After its own vaccine success, Israel is aiding vaccination drives elsewhere in the world.
On Tuesday (July 6) South Korea said it will receive 700,000 doses of the Pfizer shot from Israel on loan this week, after a surge in infections around the capital, Seoul.