Israel has registered a decline in the effectiveness of the Pfizer-BioNTech coronavirus vaccine as the Delta variant spreads across the country, the health ministry says.
Since June 6, the vaccine's effectiveness in preventing infection has dropped to 64 per cent, the ministry said.
In February, Israeli data had put the number at 95.8 per cent.
The vaccine still averted 93 per cent of severe illnesses and hospitalisations, compared to about 99 per cent in February.
The number of registered infections has been rising significantly for about two weeks in Israel, fuelled by the more virulent Delta strain first detected in India.
On Sunday, 334 people tested positive, according to the health ministry.
The last time more than 300 new cases were recorded in one day was in early April.
Many of those infected were younger people.
The number of people severely ill with COVID-19 increased slightly to 35.
No deaths related to the virus have been recorded for about two weeks.
Israel has been considered a model country in the battle against the coronavirus because of its rapid vaccination campaign.
Its current infection trends could point to struggles other countries will face, even if they have inoculated much of their populations.
Israel has a population of about 9.3 million.
Of that, 5.2 million are fully vaccinated - about 56 per cent of the population.
Israel has largely used only the Pfizer-BioNTech jab.