Dr. Todd Lee of McGill University in Canada is one such doctor who rejected the boosters. Lee contracted the B11529 omicron strain despite being triple-vaccinated.

"I have taken my last COVID-19 vaccine with RCT (randomized clinical trial) level evidence it will reduce my risk of severe disease," he tweeted. Lee alluded to the lack of results for the updated boosters, which were cleared for use in both the U.S. and Canada in the fall of last year based on data from mice experiments.

"Pay close attention to note that this isn't anti-vaccine sentiment. This is 'provide evidence of benefit to justify ongoing use,' which is very different. It is only fair for a $30 billion-a-year product given to hundreds of millions," he added.

Dr. Vinay Prasad of the University of California San Francisco (UCSF) also remarked that he will not take any additional boosters unless clinical trial data becomes available. "I took at least one dose against my will," he recounted. "It was unethical and scientifically bankrupt."