Fourth Shot Gives Protection From Covid Infection, Israel Says

A fourth vaccine dose for older adults leaves them better protected against coronavirus infection than peers who received three shots, a study released by Israel’s health ministry found. 

The preliminary analysis compares data from about 400,000 people aged 60 and over who received a fourth dose in January and some 600,000 people in the same age group who got only three doses -- with the third shot administered four months or more previously.