https://news.ycombinator.com/item?id=27943833 (29 days ago)
Also, the 39% number is the average for people vaccinated between January and July. For people vaccinated in January, the Pfizer shot is only 16% effective against the delta variant (scroll down to last page):
https://www.gov.il/BlobFolder/reports/vaccine-efficacy-safet...
Protection against severe illness is still above 85% though and declines only slowly. Besides, people vaccinated in January were mostly elderly.