With the evidence of waning immunity of the BNT162b2 vaccine, a national third dose vaccination campaign was initiated in Israel during August 2021; other countries have announced their intention to administer a booster shot as well. Leveraging data from Maccabi Healthcare Services, we conducted a preliminary retrospective study aimed at evaluating initial short-term effectiveness of a three dose versus a two dose regimen against infection due to the Delta variant of SARS-CoV-2, using two complementary approaches; a test-negative design and a matched case-control design. We found that 7-13 days after the booster shot there is a 48-68% reduction in the odds of testing positive for SARS-CoV-2 infection and that 14-20 days after the booster the marginal effectiveness increases to 70-84%. Further studies are needed to determine the duration of protection conferred by the third dose and its effect on severe disease.

Download data

• Downloaded 15,418 times
• Download rankings, all-time:
  • Site-wide: 590
  • In infectious diseases: 215
• Year to date:
  • Site-wide: 166
• Since beginning of last month:
  • Site-wide: 24

Altmetric data

Downloads over time

Distribution of downloads per paper, site-wide