240 Israelis found with COVID after vaccination, underscoring need for vigilance

 https://www.timesofisrael.com/240-israelis-diagnosed-after-vaccination-underscore-need-for-continued-vigilance/

But this process takes time, and studies of the vaccine so far have shown immunity to the virus rises only some 8-10 days after the first injection — and then only to around 50 percent effectiveness.

This is why the second dose of the vaccine, given 21 days after the first, is critical: It strengthens the immune system’s response to the virus, bringing it to 95% effectiveness and ensuring that immunity lasts. This level of immunity is only reached about a week after the second dose — or 28 days after the first.