Citing the Delta Variant, Pfizer Will Pursue Booster Shots and a New Vaccine July 08, 2021 IFTTT NYT NYT > Business NYTimes +1 pointing to evidence that the current two-dose regimen is powerfully effective against the coronavirus. Scientists were critical of the announcement IFTTT NYT NYT > Business NYTimes pointing to evidence that the current two-dose regimen is powerfully effective against the coronavirus. Scientists were critical of the announcement