Was the fourth dose of Pfizer's COVID-19 vaccine effective? -study

 https://www.jpost.com/health-and-wellness/article-710426

They found that getting the fourth shot was associated with 34% protection against infection, 64% to 67% against acute hospitalizations for mild-to-moderate and severe illness, and 72% against deaths.

Thus, the fourth shot definitely saved lives and reduced the need for acute hospitalization. However, protection against infection with the Omicron variant was only “modest,” they wrote.